Horticulturae

15 pages, 2024 KiB

Open AccessEditor’s ChoiceArticle

Effect on the Growth and Photosynthetic Characteristics of Anthurium andreanum (‘Pink Champion’, ‘Alabama’) under Hydroponic Culture by Different LED Light Spectra

by Yinglong Song, Wenqian Shang, Dandan Ma, Zheng Wang, Songlin He, Liyun Shi, Yuxiao Shen, Dan He, Erqiang Wang and Xiaohui Wang

Horticulturae 2022, 8(5), 389; https://doi.org/10.3390/horticulturae8050389 - 28 Apr 2022

Cited by 7 | Viewed by 3053

Abstract

Anthurium andreanum was one of the best indoor ornamental plants. Two cultivars of Anthurium andreanum (Pink Champion, Alabama) were used to investigate the effects of light quality on physiological and biochemical indexes. There were six different light quality treatments: Fluorescent Daylight Lamp (CK), [...] Read more.

Anthurium andreanum was one of the best indoor ornamental plants. Two cultivars of Anthurium andreanum (Pink Champion, Alabama) were used to investigate the effects of light quality on physiological and biochemical indexes. There were six different light quality treatments: Fluorescent Daylight Lamp (CK), and RB (100% Blue, 60% R + 40% B, 70% R + 30% B, 80% R + 20% B, 100% Red) provided by light emitting diodes (LED). The results showed that blue light was beneficial to shoot growth and dry matter accumulation, photosynthetic rate, soluble sugar, and POD activities. Red light was beneficial for the synthesis and accumulation of soluble protein, and could promote root growth. ‘Pink Champion’ and ‘Alabama’ obtained the relatively better morphological parameters, chlorophyll contents, photosynthetic parameters, and antioxidant enzyme activities in 7:3 and 6:4 treatments. The antioxidant enzyme (POD, SOD) activities under composite light of red and blue treatments were better than that of monochromatic red, blue light treatments and CK on the whole. Comprehensive evaluation showed that the treatment of 7:3 was a suitable light environment indoors and could be used as the preferred light quality ratio in the production and application of Anthurium andreanum. Full article

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22 pages, 396 KiB

Open AccessEditor’s ChoiceArticle

Assessment of Physicochemical, Macro- and Microelements, Heavy Metals, and Related Human Health Risk from Organically, Conventionally, and Homemade Romanian Wines

by Florin Dumitru Bora, Anamaria Călugăr, Claudiu-Ioan Bunea, Sandor Rozsa and Andrea Bunea

Horticulturae 2022, 8(5), 382; https://doi.org/10.3390/horticulturae8050382 - 27 Apr 2022

Cited by 1 | Viewed by 3389

Abstract

From the consumers’ perspective, organic and homemade products have become more attractive than conventional ones. However, scientific data regarding the characteristics, properties, and composition of these products are scarce. This study assessed the elemental composition of organic, conventional, and homemade Romanian wines. The [...] Read more.

From the consumers’ perspective, organic and homemade products have become more attractive than conventional ones. However, scientific data regarding the characteristics, properties, and composition of these products are scarce. This study assessed the elemental composition of organic, conventional, and homemade Romanian wines. The physicochemical composition, SO₂ (free and total) and total concentration of macroelements, microelements, and heavy metals from nine wine regions containing 165 samples of white (38 organic/70 conventional/57 homemade), 67 red (22/31/14) and 7 rosé (2/2/3) wines were analyzed by inductively coupled plasma mass spectrometry. Dietary intake and target hazard quotient were also evaluated. The phytochemical and elemental compositions of the wine samples varied across regions and wine types. The highest levels of Ca, K, Fe and Al were detected in conventional wines, while homemade wines recorded high concentrations of Na, Mg, V, Ba and Rb. In the case of the rosé wine samples, the levels of trace elements and heavy metals were below the admissible limit. The estimated daily intake of a glass of wine provided less than 0.5% of the tolerable daily intake of the analyzed elements. No health concerns were identified. All wine samples can be safely consumed, regardless of the culture system used for production, and homemade wines are not of a lower quality than organic or conventional wines. Full article

(This article belongs to the Section Viticulture)

18 pages, 1621 KiB

Open AccessEditor’s ChoiceReview

Sanitary Registries and Popular Medicinal Plants Used in Medicines and Herbal Remedies in Mexico (2001–2020): A Review and Potential Perspectives

by Aida Araceli Rodríguez-Hernández, Fernanda Guadalupe Flores-Soria, Omar Patiño-Rodríguez and Abraham Escobedo-Moratilla

Horticulturae 2022, 8(5), 377; https://doi.org/10.3390/horticulturae8050377 - 26 Apr 2022

Cited by 9 | Viewed by 3710

Abstract

Mexico, a megadiverse country, hosts approximately 10–12% of the world’s biodiversity and at least 21,989–23,424 vascular plants, 3350 of which are traditional medicinal flora. The Mexican Regulation categorizes herbal medicinal products into two groups: herbal medicines products and herbal remedies products. To date, [...] Read more.

Mexico, a megadiverse country, hosts approximately 10–12% of the world’s biodiversity and at least 21,989–23,424 vascular plants, 3350 of which are traditional medicinal flora. The Mexican Regulation categorizes herbal medicinal products into two groups: herbal medicines products and herbal remedies products. To date, there is no available information that describes and includes analyzed data about these two types of herbal medicinal products registered in Mexico. The purpose of the study was to analyze national sanitary registries of herbal products from 2001 to 2020 and identify native Mexican plants that are most used in herbal products. Further, the study aims to highlight the impact and relevance of this large number of medicinal plants, which represent a great source of information, genetic resources, bioactive compounds, and potential use in subsequent therapies based on scientific evidence. The future of medicines and herbal remedies is underestimated; thus, the significance of evaluating the great potential in studying plants for medicinal use must be taken into account. Full article

(This article belongs to the Special Issue Botany, Phytochemistry and Pharmacology in Traditional Herbal Medicine)

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12 pages, 1000 KiB

Open AccessEditor’s ChoiceArticle

Cold Treatment Modulates Changes in Primary Metabolites and Flowering of Cut Flower Tulip Hybrids

by Petronia Carillo, Giovanna Marta Fusco, Rosaria Serena Del Gaudio, Stefania De Pascale and Roberta Paradiso

Horticulturae 2022, 8(5), 371; https://doi.org/10.3390/horticulturae8050371 - 24 Apr 2022

Cited by 2 | Viewed by 2500

Abstract

Tulip is one of the most important bulbous genera in the world’s floriculture. It is known that cold exposure of bulbs before planting is required to break the bulb dormancy and to promote the plant’s flowering. Preparation procedures performed by breeders differ in [...] Read more.

Tulip is one of the most important bulbous genera in the world’s floriculture. It is known that cold exposure of bulbs before planting is required to break the bulb dormancy and to promote the plant’s flowering. Preparation procedures performed by breeders differ in the duration and the thermal level, and the choice of the procedure depends on the genotype’s sensitivity to temperature; however, little is known about the metabolic responses underlying the different behaviours of the numerous commercial hybrids. We evaluated the influence of two bulb-preparation procedures, 15–18 weeks at 5 ÷ 9 °C, and 9–14 weeks at 2 ÷ 5 °C, in two hybrids of tulip (Tulipa gesneriana L.), ‘Royal Virgin’ and ‘Ad Rem’, grown hydroponically in a floating system. Tulip plants of the two hybrids responded differently to bulb exposure to low temperatures in terms of early flowering, as this was unaffected by the preparation procedure in ‘Royal Virgin’ (27.1 days from transplanting, on average), while it was earlier after treatment at higher temperatures compared with lower temperatures in ‘Ad Rem’ (24.1 vs. 26.7 days at 5 °C vs. at 9 °C). This different flowering earliness may be related to the diverse metabolic responses enacted by the bulbs for cold acclimation that depended on hybrid x thermal treatment. Plant leaf area and flower stem characteristics were similar in the hybrids and were unaffected by the bulb-preparation procedure. Full article

(This article belongs to the Section Floriculture, Nursery and Landscape, and Turf)

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11 pages, 1978 KiB

Open AccessEditor’s ChoiceArticle

Use of Piriformospora indica to Promote Growth of Strawberry Daughter Plants

by Wei Liu, Min Tan, Pengyan Qu, Chensi Huo, Wenjie Liang, Runlin Li, Yan Jia, Xinping Fan and Chunzhen Cheng

Horticulturae 2022, 8(5), 370; https://doi.org/10.3390/horticulturae8050370 - 23 Apr 2022

Cited by 6 | Viewed by 2799

Abstract

As an endophytic fungus, the growth-promoting effects of Piriformospora indica have been widely confirmed in many of its host plants. In this study, we investigated the influences of P. indica colonization on the growth of the daughter plants of two strawberry cultivars, ‘Benihoppe’ [...] Read more.

As an endophytic fungus, the growth-promoting effects of Piriformospora indica have been widely confirmed in many of its host plants. In this study, we investigated the influences of P. indica colonization on the growth of the daughter plants of two strawberry cultivars, ‘Benihoppe’ and ‘Sweet Charlie.’ The results showed that the fungus colonization significantly promoted the growth of the daughter plants of both of the two strawberry varieties. Its colonization greatly improved almost all of the growth parameters of the ‘Benihoppe’ daughter plants, including the above-ground fresh weight, above-ground dry weight, root fresh weight, root dry weight, plant height, petiole length, leaf area, number of roots and chlorophyll content. However, the fungus colonization showed significant improving effects on only the above-ground fresh weight, root fresh weight and root dry weight of ‘Sweet Charlie.’ Surprisingly, the average root length of ‘Benihoppe’ and ‘Sweet Charlie’ was suppressed by about 14.3% and 24.6%, respectively, by P. indica. Moreover, after P. indica colonization, the leaf nitrate reductase activity and root activity upregulated by 30.12% and 12.74%, and 21.85% and 21.16%, respectively, for the ‘Benihoppe’ and ‘Sweet Charlie’ daughter plants. Our study indicated that P. indica could promote the growth of strawberry daughter plants by improving rooting, strengthening photosynthetic pigments production and nutrient absorption and accelerating biomass accumulation. The fungus shows great potential to be used in the strawberry industry, especially in the breeding of daughter plants. Full article

(This article belongs to the Special Issue Mycorrhizal Roles in Horticultural Plants)

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20 pages, 1471 KiB

Open AccessEditor’s ChoiceReview

Hormonal Signaling in the Progamic Phase of Fertilization in Plants

by Ekaterina V. Zakharova, Marat R. Khaliluev and Lidia V. Kovaleva

Horticulturae 2022, 8(5), 365; https://doi.org/10.3390/horticulturae8050365 - 21 Apr 2022

Cited by 6 | Viewed by 3590

Abstract

Pollen–pistil interaction is a basic process in the reproductive biology of flowering plants and has been the subject of intense fundamental research that has a pronounced practical value. The phytohormones ethylene (ET) and cytokinin (CK) together with other hormones such as auxin, gibberellin [...] Read more.

Pollen–pistil interaction is a basic process in the reproductive biology of flowering plants and has been the subject of intense fundamental research that has a pronounced practical value. The phytohormones ethylene (ET) and cytokinin (CK) together with other hormones such as auxin, gibberellin (GA), jasmonic acid (JA), abscisic acid (ABA), and brassinosteroids (BRs) influence different stages of plant development and growth. Here, we mainly focus on the information about the ET and CK signaling in the progamic phase of fertilization. This signaling occurs during male gametophyte development, including tapetum (TAP) cell death, and pollen tube growth, including synergid programmed cell death (PCD) and self-incompatibility (SI)-induced PCD. ET joins the coordination of successive events in the developing anther, including the TAP development and cell death, anther dehiscence, microspore development, pollen grain maturation, and dehydration. Both ET and CK take part in the regulation of pollen–pistil interaction. ET signaling accompanies adhesion, hydration, and germination of pollen grains in the stigma and growth of pollen tubes in style tissues. Thus, ET production may be implicated in the pollination signaling between organs accumulated in the stigma and transmitted to the style and ovary to ensure successful pollination. Some data suggest that ET and CK signaling are involved in S-RNase-based SI. Full article

(This article belongs to the Special Issue Physiology and Molecular Biology of Flowering, Fruit Setting, Fruit Quality)

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16 pages, 3401 KiB

Open AccessEditor’s ChoiceArticle

Genome-Wide Analyses of Tea Plant Stress-Associated Proteins (SAPs) Reveal the Role of CsSAP12 in Increased Drought Tolerance in Transgenic Tomatoes

by Shu-Chen Fan, Chun Li, Shao-Hua Li, Jie Tang, Hong-Di Shi, Tian-Ming Yang, Ming-Zhi Liang and Dan-Dan Liu

Horticulturae 2022, 8(5), 363; https://doi.org/10.3390/horticulturae8050363 - 21 Apr 2022

Cited by 4 | Viewed by 2292

Abstract

Plant stress-associated proteins (SAPs) contain A20/AN1 zinc finger domains and are involved in plant response to abiotic stresses. In this study, we aimed to explore the biological function of tea plant CsSAPs. A total of 14 CsSAP genes were identified in the tea [...] Read more.

Plant stress-associated proteins (SAPs) contain A20/AN1 zinc finger domains and are involved in plant response to abiotic stresses. In this study, we aimed to explore the biological function of tea plant CsSAPs. A total of 14 CsSAP genes were identified in the tea plant genome using a reference genome database (Camellia sinensis var. sinensis). The CsSAPs were divided into the following two groups: Group I, containing one AN1 domain and/or one A20 domain; and Group II, containing two AN1 domains and/or two C2H2 domains. The sequence alignments and conserved domains analysis indicated that the CsSAPs were highly structurally conserved in terms of amino acid sequence and protein structure. The CsSAPs showed different transcript levels in spatio-temporal expression and in response to cold and drought stress in tea plants. Furthermore, the expression of CsSAP12 was considerably upregulated under drought stress. The overexpression of CsSAP12 in transgenic tomatoes showed increased tolerance to drought stress compared with the wild type. Altogether, the results showed that CsSAP12 might be involved in drought stress. Thus, CsSAP12 might be a target gene in genetic engineering to improve drought tolerance in tea plants. Full article

(This article belongs to the Topic Physiological and Molecular Characterization of Crop Tolerance to Abiotic Stresses)

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15 pages, 2127 KiB

Open AccessEditor’s ChoiceArticle

Irrigation Levels and Fertilization Rates as Pre-Harvest Factors Affecting the Growth and Quality of Hippeastrum

by Chaiartid Inkham, Kanokwan Panjama and Soraya Ruamrungsri

Horticulturae 2022, 8(4), 345; https://doi.org/10.3390/horticulturae8040345 - 18 Apr 2022

Cited by 1 | Viewed by 2705

Abstract

Growing Hippeastrum in an open field or a greenhouse requires precision irrigation and fertilizer to promote plant growth and development. Therefore, this research aimed to study the effect of irrigation level combined with fertilization rate on the growth and development of Hippeastrum. [...] Read more.

Growing Hippeastrum in an open field or a greenhouse requires precision irrigation and fertilizer to promote plant growth and development. Therefore, this research aimed to study the effect of irrigation level combined with fertilization rate on the growth and development of Hippeastrum. Two experiments were carried out to determine the influence of irrigation and fertilizer on the growth, flowering, and bulb quality of Hippeastrum. In the first experiment, bulbs of Hippeastrum ‘Red Lion’ with circumferences of 25 cm were grown in plastic plots using mixed soil as growing media under a 50% shading net. Plants were irrigated daily until drainage and water contained in macropores by gravity action (Field capacity: FC) for 90 days after planting (DAP) and supplied with three different 15N-15P₂O₅-15K₂O fertilization rates, i.e., 0, 2.5, and 5 g per pot. Plant growth and water use efficiency were measured at 45, 60, and 90 DAP. The results showed that plants supplied with 0 g of fertilizer had the lowest plant height and number of leaves per plant at 90 DAP, whereas there was no significant effect of fertilizer rate treatments on flower quality. The water use efficiency, evapotranspiration rate (ET), crop evapotranspiration under standard condition (ETc), crop coefficient (Kc), photosynthetic rate, and stomatal conductance were decreased when plants were supplied with fertilizer at a rate of 0 g per pot at 90 DAP. In the second experiment, plants were irrigated with four levels, i.e., 100, 75, 50, and 25% ETc combined with three fertilization rates, i.e., 0, 2.5, and 5 g per pot. At 180 DAP, the results showed that water deficit treatment (50 and 25% ETc) decreased plant growth and bulb quality. Irrigation with 100% ETc combined with 2.5 or 5 g per pot and irrigation with 75% ETc combined with 5 g per pot were the optimum levels to promote plant growth and bulb quality in Hippeastrum. Full article

(This article belongs to the Special Issue Factors Affecting Export Flower Quality and Strategies for Prolonging Flowers Vase Life)

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7 pages, 922 KiB

Open AccessEditor’s ChoiceArticle

Growth Characteristics of Lettuce Relative to Generation Position of Air Anions in a Closed-Type Plant Factory

by Jin-Ho Won, Byeong-Hyo Cho, Yong-Hyeon Kim and Jung-Hyun Lee

Horticulturae 2022, 8(4), 346; https://doi.org/10.3390/horticulturae8040346 - 18 Apr 2022

Cited by 1 | Viewed by 2287

Abstract

(1) Background: We studied how the generation position of air anions in a closed-type plant factory affects the growth characteristics of lettuce and identified the optimal position. (2) Methods: We used LEDs (red/green/blue = 8:1:1) as a light source and set the temperature [...] Read more.

(1) Background: We studied how the generation position of air anions in a closed-type plant factory affects the growth characteristics of lettuce and identified the optimal position. (2) Methods: We used LEDs (red/green/blue = 8:1:1) as a light source and set the temperature and RH of the plant factory to 20 ± 2 ℃ and 50% ± 5%, respectively. We grew lettuce under three air anion conditions—sideward, upward, and downward—and compared the growth characteristics to those of a control grown without air anions. We measured the growth characteristics of the lettuce at 3 and 4 weeks after sowing, and the measurement items were shoot fresh weight (FW) and dry weight (DW); leaf area (LA), length (LL), and width (LW); SPAD; antioxidant capacity; and total phenol content. (3) Results: At 4 weeks, FW in the downward treatment condition was 25.3% higher than in the control, and DW showed a similar difference. LA was about 1943.94 cm²/plant in the downward treatment condition, which was about 15.5% higher than in the control. (4) Conclusions: We conclude that air anion generation has a positive effect on lettuce growth, and the optimal generation position for air anions is downward. Full article

(This article belongs to the Section Vegetable Production Systems)

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15 pages, 1763 KiB

Open AccessEditor’s ChoiceArticle

The True Identity of the “Second Pollen Morphology” of Camellia oleifera—Stomium Cells

by Yang Hu and Chao Gao

Horticulturae 2022, 8(4), 347; https://doi.org/10.3390/horticulturae8040347 - 18 Apr 2022

Cited by 1 | Viewed by 2658

Abstract

Previous studies on Camellia oleifera pollen morphology have indicated dual morphologies, defined as “dimorphism”. However, they were limited to morphological studies at the end of final development and did not elucidate the origin, structure, and function of the second pollen morphology (striate pollen). [...] Read more.

Previous studies on Camellia oleifera pollen morphology have indicated dual morphologies, defined as “dimorphism”. However, they were limited to morphological studies at the end of final development and did not elucidate the origin, structure, and function of the second pollen morphology (striate pollen). In this study, the differences between the two “pollen” types were compared by paraffin sections, scanning electron microscopy (SEM), fluorescence microscopy, and in vitro germination. The results clearly showed that the second pollen type was formed by stomium cells of the anther, which is responsible for anther dehiscence. The nucleus and vesicles of the stomium cell were specifically distributed during anther development, which may be related to the formation of the septum, pollen dispersal activity, and the increase in stomium cell count; at the microscopic level, the stomium cell mainly consisted of the cell wall, large vesicles, and nucleus. The large vesicles facilitate the rapid dehydration of stomium cells under suitable conditions for anther dehiscence. Furthermore, studies on other species of the genus Camellia have suggested that the second type of pollen morphology is pseudopollen, which is capable of partaking in deceptive pollination. The present study refuted this theory and suggested that the pseudopollen are stomium cells, whose structure relates to their function. These results provide the basis for further research on C. oleifera pollen physiology toward the improvement of pollination rates with agricultural practices or breeding interventions. Full article

(This article belongs to the Section Propagation and Seeds)

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19 pages, 2538 KiB

Open AccessEditor’s ChoiceArticle

Combining Cultural Tactics and Insecticides for the Management of the Sweetpotato Whitefly, Bemisia tabaci MEAM1, and Viruses in Yellow Squash

by Angela Gabrielle LaTora, Clarence Bagayao Codod, Saioa Legarrea, Bhabesh Dutta, Robert C. Kemerait, Jr., Scott Adkins, William Turechek, Timothy Coolong, Andre Luiz Biscaia Ribeiro da Silva and Rajagopalbabu Srinivasan

Horticulturae 2022, 8(4), 341; https://doi.org/10.3390/horticulturae8040341 - 17 Apr 2022

Cited by 11 | Viewed by 3623

Abstract

The sweetpotato whitefly, Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), and the complex of viruses it transmits are major limiting factors to squash production in the southeastern United States. At this time, insecticides are extensively relied upon for the management of whiteflies and, indirectly, [...] Read more.

The sweetpotato whitefly, Bemisia tabaci MEAM1 Gennadius (Hemiptera: Aleyrodidae), and the complex of viruses it transmits are major limiting factors to squash production in the southeastern United States. At this time, insecticides are extensively relied upon for the management of whiteflies and, indirectly, whitefly-transmitted viruses. The development of a multi-faceted, integrated pest management (IPM) program is needed to increase the sustainability and profitability of squash production. Experiments in 2018 and 2019 evaluated the effects of insect exclusion netting (IEN) in combination with selected pesticides on whitefly population dynamics and virus incidence in greenhouse-grown squash seedlings. Field experiments from 2018 to 2021 evaluated the effects of mulch type (UV-reflective mulch, live mulch, and white plastic mulch), row covers, and insecticides on whitefly population dynamics, silver leaf disorder (SSL) intensity, virus symptom severity, and marketable yield. IEN significantly reduced whiteflies and virus incidence on squash seedlings in the greenhouse study. In the field mulch study, lower whitefly abundance and SSL intensity, as well as reduced virus symptom severity, were observed in plots with reflective mulch compared with white plastic or live mulch. In the insecticide/row cover study, whitefly abundance, SSL intensity, and virus symptom severity were lowest in the row cover and cyantraniliprole- and flupyradifurone-treated plots. Field plots with row covers and those with UV-reflective mulch consistently produced the greatest marketable yields. These findings demonstrate that growers can reduce whitefly and virus pressure and preserve yields in squash production in the southeastern United States by combining cultural and chemical tactics, including row covers, UV-reflective mulch, and select insecticides. Full article

(This article belongs to the Special Issue Implementation of IPM Measures in Vegetable Cropping Systems)

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14 pages, 14388 KiB

Open AccessEditor’s ChoiceArticle

Impact of Pseudomonas sp. SVB-B33 on Stress- and Cell Wall-Related Genes in Roots and Leaves of Hemp under Salinity

by Roberto Berni, Jean-Francois Hausman, Silas Villas-Boas and Gea Guerriero

Horticulturae 2022, 8(4), 336; https://doi.org/10.3390/horticulturae8040336 - 15 Apr 2022

Cited by 6 | Viewed by 2455

Abstract

Salinity is a type of abiotic stress that negatively affects plant growth and development. Textile hemp (Cannabis sativa L.) is an important multi-purpose crop that shows sensitivity to salt stress in a genotype- and developmental stage-dependent manner. The root and shoot biomasses [...] Read more.

Salinity is a type of abiotic stress that negatively affects plant growth and development. Textile hemp (Cannabis sativa L.) is an important multi-purpose crop that shows sensitivity to salt stress in a genotype- and developmental stage-dependent manner. The root and shoot biomasses decrease in the presence of NaCl during vegetative growth and several stress-responsive genes are activated. Finding environmentally friendly ways to increase plant health and resilience to exogenous stresses is important for a sustainable agriculture. In this context, the use of beneficial bacteria, collectively referred to as plant growth-promoting bacteria (PGPB), is becoming an attractive and emergent agricultural strategy. In this study, data are provided on the effects of a Pseudomonas isolate (Pseudomonas sp. SVB-B33) phylogenetically closely related to P. psychrotolerans applied via roots to salt-stressed hemp. The application of both living and dead bacteria impacts the fresh weight of the root biomass, as well as the expression of several stress-related genes in roots and leaves. These results pave the way to future investigations on the use of Pseudomonas sp. SVB-B33 in combination with silica to mitigate stress symptoms and increase the resilience to other forms of exogenous stresses in textile hemp. Full article

(This article belongs to the Special Issue Cell Wall Composition and Extract)

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16 pages, 30508 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Woody Canker and Shoot Blight Caused by Botryosphaeriaceae and Diaporthaceae on Mango and Litchi in Italy

by Dalia Aiello, Vladimiro Guarnaccia, Mariangela Benedetta Costanzo, Giuseppa Rosaria Leonardi, Filomena Epifani, Giancarlo Perrone and Giancarlo Polizzi

Horticulturae 2022, 8(4), 330; https://doi.org/10.3390/horticulturae8040330 - 14 Apr 2022

Cited by 14 | Viewed by 3323

Abstract

In recent years, the cultivation of tropical fruit crops has increased in the Mediterranean basin, especially in southern Italy. In surveys conducted from 2014 to 2019 woody canker and shoot blight were observed on mango plants (cvs. Kent, Keitt, Sensation, Osteen, and Kensington [...] Read more.

In recent years, the cultivation of tropical fruit crops has increased in the Mediterranean basin, especially in southern Italy. In surveys conducted from 2014 to 2019 woody canker and shoot blight were observed on mango plants (cvs. Kent, Keitt, Sensation, Osteen, and Kensington Pride) and litchi plants (cvs. Way Chee and Kwai Mai Pink) cultivated in Sicily. Botryosphaeriaceae and Diaporthaceae were consistently isolated from symptomatic samples. Morphological characterization and multi-locus phylogenies using three genomic loci (a portion of translation elongation factor 1-α gene, a portion of the β-tubulin gene, and an internal transcribed spacer) identified these fungi as Neofusicoccum parvum, Lasiodiplodia theobromae, Botryosphaeria dothidea, Diaporthe foeniculina, and Diaporthe baccae on mango and Diaporthe foeniculina and Diaporthe rudis on litchi. Pathogenicity tests on healthy mango (cv. Kensington Pride) and litchi (cv. Way Chee) plants demonstrated the pathogenicity of the isolates used in the study, and Koch’s postulates were fulfilled for all pathogens. To our knowledge, this is the first report of L. theobromae, B. dothidea, and Diaporthe species on mango in Italy and the first report worldwide of woody canker and shoot blight caused by D. foeniculina and D. rudis on litchi plants. Full article

(This article belongs to the Special Issue Pathogens and Disease Control of Fruit Trees)

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14 pages, 520 KiB

Open AccessEditor’s ChoiceReview

How to Measure Organic Fruit Consumer Behavior: A Systematic Review

by Alejandro Vega-Muñoz, Miseldra Gil-Marín, Nicolás Contreras-Barraza, Guido Salazar-Sepúlveda and Analia Verónica Losada

Horticulturae 2022, 8(4), 318; https://doi.org/10.3390/horticulturae8040318 - 9 Apr 2022

Cited by 3 | Viewed by 3415

Abstract

This review article seeks to systematically identify appropriate ways to measure the consumption behavior of organic fruits. The systematic review of the literature was performed according to the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the [...] Read more.

This review article seeks to systematically identify appropriate ways to measure the consumption behavior of organic fruits. The systematic review of the literature was performed according to the criteria of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the eligibility criteria were declared through the PICOS (population, interventions, comparators, outcomes, and study) tool based on 277 article records scientiometrically identified in both the Journal Citation Report databases from Web of Science. The literature review stages determined a reduced set of articles that presented valid and reliable measurement scales that covered determinant constructs in organic fruit consumer behavior (OFCB). The measurement scale with the best results reported within the screened articles covered the constructs related to health, fear, environment, effort, and economy, allowing it to serve as a reference instrument in further studies on food consumer behavior. Full article

(This article belongs to the Collection Horticultural Economics, Policy, Business Management and Marketing: The Challenge of Sustainability)

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15 pages, 2388 KiB

Open AccessEditor’s ChoiceArticle

Genetic Analysis of the Grapevine GATA Gene Family and Their Expression Profiles in Response to Hormone and Downy Mildew Infection

by Tingting Chen, Jing Peng, Meijie Li, Mengru Dou, Yan Lei, Yuejing Wang and Yan Xu

Horticulturae 2022, 8(4), 303; https://doi.org/10.3390/horticulturae8040303 - 3 Apr 2022

Cited by 3 | Viewed by 2308

Abstract

Grapevine (Vitis. vinifera L.) is one of the most economically important fruit crops throughout the world. However, grape production is increasingly impacted by numerous diseases, including downy mildew, caused by the oomycete Plasmopara viticola. In grapevine and other plants, members of [...] Read more.

Grapevine (Vitis. vinifera L.) is one of the most economically important fruit crops throughout the world. However, grape production is increasingly impacted by numerous diseases, including downy mildew, caused by the oomycete Plasmopara viticola. In grapevine and other plants, members of the GATA family of transcription factors play key roles in light and phytohormone signaling. However, little is known about their potential roles in biotic defense responses. As a first step, we identified 27 GATA transcription factors in grapevine and defined their transcriptional responses to three biotic stress-related phytohormones (SA, MeJA, and BR) in callus cells, and challenge with P. viticola in a downy mildew-sensitive cultivar, V. vinifera ‘Pinot noir’, and a resistant cultivar, V. piasezkii ‘Liuba-8′. Many of the VvGATA genes had higher expression at 0.5 h after hormones treatments. Moreover, a group of VvGATAs was dramatically induced in ‘Liuba-8′ at 24 post infection by P. viticola. However, the same genes were significantly repressed and showed low expression levels in ‘Pinot noir’. Additionally, VvGATA27 was located in the nucleus and had transcriptional activity. Taken together, the study identified the GATA full gene families in grapes on phylogenetic analysis and protein structure. Moreover, this study provided a basis for discussing the roles of VvGATAs in response to hormones and P. viticola infection. Our results provided evidence for the selection of candidate genes against downy mildew and lay the foundation for further investigation of VvGATA transcription factors. Full article

(This article belongs to the Special Issue Stress Biology of Horticultural Plants)

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12 pages, 2640 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Application of an Alternative Nutrient Replenishment Method to Electrical Conductivity-Based Closed-Loop Soilless Cultures of Sweet Peppers

by Tae-In Ahn and Jung-Eek Son

Horticulturae 2022, 8(4), 295; https://doi.org/10.3390/horticulturae8040295 - 30 Mar 2022

Cited by 6 | Viewed by 2248

Abstract

The nutrient replenishment method primarily impacts the nutrient variations in a closed-loop soilless culture system. However, there is still a lack of systematic approaches for the effective way of nutrient replenishment. Our previous study theoretically derived and experimentally validated an alternative nutrient replenishment [...] Read more.

The nutrient replenishment method primarily impacts the nutrient variations in a closed-loop soilless culture system. However, there is still a lack of systematic approaches for the effective way of nutrient replenishment. Our previous study theoretically derived and experimentally validated an alternative nutrient replenishment method expecting synchronized total fertilizer supply to total nutrient absorption by crops and lower concentration fluctuations than conventional methods. However, no individual nutrient management has been performed. The objective of this study was to apply individual nutrient management to the alternative nutrient replenishment technique under experimental- and commercial-scale electrical conductivity (EC)-based closed-loop soilless cultures. Automated nutrient solution mixing modules and sweet peppers grown on rockwool slabs were used. Nutrient concentrations and crop productivity were compared between the closed-loop system using the alternative nutrient replenishment and the conventional open-loop systems. During early treatment, rapid decreases in K⁺ and H₂PO₄⁻ were observed in the closed-loop system. However, after the stock solution nutrient adjustment, the decreasing trend was stabilized and returned close to initial concentrations. No significant differences in sugar content, incidence of blossom-end rot, and productivity of sweet peppers were observed between the closed- and open-loop soilless cultures. We confirmed that the nutrient variation stabilizing effect of the alternative nutrient replenishment method was valid under nutrient adjustment conditions and had comparable nutrient management performance with the open-loop system. Full article

(This article belongs to the Special Issue Hydroponics in Vegetable Production)

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22 pages, 489 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Willingness-to-Pay for Produce: A Meta-Regression Analysis Comparing the Stated Preferences of Producers and Consumers

by Alice Kilduff and Daniel Tregeagle

Horticulturae 2022, 8(4), 290; https://doi.org/10.3390/horticulturae8040290 - 29 Mar 2022

Cited by 3 | Viewed by 2976

Abstract

Willingness-to-pay (WTP) estimates help agribusinesses estimate whether a new product is likely to be profitable. For produce, new products, such as new fruit varieties, need to be adopted by producers before they can be sold to consumers. The study of ex ante fruit [...] Read more.

Willingness-to-pay (WTP) estimates help agribusinesses estimate whether a new product is likely to be profitable. For produce, new products, such as new fruit varieties, need to be adopted by producers before they can be sold to consumers. The study of ex ante fruit and vegetable producer preferences is relatively new. This study uses meta-regression analysis to compare the estimated WTP premium between U.S. producers and consumers to determine whether they differ. After controlling for differences in study methods, product attributes, and potential publication bias, the producer WTP was between 14.16 and 27.73 percentage points higher. Subject to several caveats and limitations, this suggests that consumer WTP can be a sufficient metric for the profitability of new produce products. Full article

(This article belongs to the Special Issue Economics and Management of Fruit and Vegetable Production)

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16 pages, 3594 KiB

Open AccessEditor’s ChoiceArticle

Weather Conditions Influence on Lavandin Essential Oil and Hydrolate Quality

by Milica Aćimović, Biljana Lončar, Jovana Stanković Jeremić, Mirjana Cvetković, Lato Pezo, Milada Pezo, Marina Todosijević and Vele Tešević

Horticulturae 2022, 8(4), 281; https://doi.org/10.3390/horticulturae8040281 - 27 Mar 2022

Cited by 20 | Viewed by 2926

Abstract

Lavandula sp. essential oil and hydrolate are commercially valuable in various industry branches with the potential for wide-ranging applications. This study aimed to evaluate the quality of these products obtained from L. x intermedia cv. ‘Budrovka’ for the first time cultivated on Fruška [...] Read more.

Lavandula sp. essential oil and hydrolate are commercially valuable in various industry branches with the potential for wide-ranging applications. This study aimed to evaluate the quality of these products obtained from L. x intermedia cv. ‘Budrovka’ for the first time cultivated on Fruška Gora Mt. (Serbia) during three successive seasons (2019, 2020, and 2021). Essential oil extraction was obtained by steam distillation, and the composition and influence of weather conditions were also assessed, using flowering tops. The obtained essential oils and hydrolates were analysed by gas chromatography with a flame ionization detector (GC-FID) and gas chromatography coupled to mass spectrometry (GC-MS). A linear regression model was developed to predict L. x intermedia cv. ‘Budrovka’ essential oil volatile compound content and hydrolate composition during three years, according to temperature and precipitation data, and the appropriate regression coefficients were calculated, while the correlation analysis was employed to analyse the correlations in hydrolate and essential oil compounds. To completely describe the structure of the research data that would present a better insight into the similarities and differences among the diverse L. x intermedia cv. ‘Budrovka’ samples, the PCA was used. The most dominant in L. intermedia cv. ‘Budrovka’ essential oil and hydrolate were oxygenated monoterpenes: linalool, 1,8-cineole, borneol, linalyl acetate, and terpinene-4-ol. It is established that the temperature was positively correlated with all essential oil and hydrolate compounds. The precipitations were positively correlated with the main compounds (linalool, 1,8-cineole, and borneol), while the other compounds’ content negatively correlated to precipitation. The results indicated that Fruška Gora Mt. has suitable agro-ecological requirements for cultivating Lavandula sp. and providing satisfactory essential oil and hydrolate. Full article

(This article belongs to the Special Issue Medicinal, Aromatic, Spice Plants: Biodiversity, Phytochemistry, Bioactivity and Their Processing Innovation)

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11 pages, 253 KiB

Open AccessEditor’s ChoiceArticle

Producing Cherry Tomatoes in Urban Agriculture

by Matthew L. Richardson and Caitlin G. Arlotta

Horticulturae 2022, 8(4), 274; https://doi.org/10.3390/horticulturae8040274 - 22 Mar 2022

Cited by 7 | Viewed by 3850

Abstract

Agriculture in urban and urbanizing areas will be increasingly critical to enhancing food security and food sovereignty, creating income, strengthening social interactions, and improving health outcomes in cities. We used three roofs, a hydroponic system, an aquaponic system, and field rows in an [...] Read more.

Agriculture in urban and urbanizing areas will be increasingly critical to enhancing food security and food sovereignty, creating income, strengthening social interactions, and improving health outcomes in cities. We used three roofs, a hydroponic system, an aquaponic system, and field rows in an urban environment to grow six dwarf tomato cultivars: ‘Micro Tom’, ‘Red Robin’, ‘Sweet ‘n’ Neat’, ‘Terenzo’, ‘Tiny Tim’, and ‘Tumbler.’ We measured the marketable yield and non-marketable yield, mass of non-marketable tomatoes exhibiting defects, and the content of 12 mineral nutrients in fruits. We found the productivity often varied among cultivars within a cropping system. ‘Terenzo’ and ‘Tumbler’ were always some of the most productive cultivars, whereas ‘Micro Tom’ was normally among the least productive cultivars. The production from ‘Red Robin’, ‘Tiny Tim’, and ‘Sweat ‘n’ Neat’ was more variable, sometimes producing high, moderate, or low mass. The mineral content was especially variable across the cultivars and we did not identify cultivars that were consistently high or low in mineral content across systems, indicating that the mineral content was highly influenced by a genotype x environment interaction. The amount of 5 minerals differed across cultivars in aquaponics, 9 differed in hydroponics, and 6–12 differed in the roof systems. A high-yielding cultivar should be selected first and production methods can then be modified to maximize the nutrient content. Full article

(This article belongs to the Special Issue Urban Horticulture - New Trends and Technologies)

15 pages, 3127 KiB

Open AccessEditor’s ChoiceArticle

Characterization of Young Shoot Population, Yield, and Nitrogen Demands of Tea (Camellia sinensis L.) Harvested under Different Standards

by Lizhi Long, Yuanzhi Shi, Lifeng Ma and Jianyun Ruan

Horticulturae 2022, 8(4), 275; https://doi.org/10.3390/horticulturae8040275 - 22 Mar 2022

Cited by 5 | Viewed by 2617

Abstract

The quality of green tea is greatly influenced by the harvest standards for young shoots. The present field experiment was conducted to characterize the young shoot populations, yields, and nitrogen (N) demands of tea plants subjected to four different harvest standards, i.e., buds [...] Read more.

The quality of green tea is greatly influenced by the harvest standards for young shoots. The present field experiment was conducted to characterize the young shoot populations, yields, and nitrogen (N) demands of tea plants subjected to four different harvest standards, i.e., buds with one, two, or three young expanding leaves (referred to as B1L, B2L, and B3L, respectively) and a combination of B1L and B3L (B1L/B3L) throughout the year. Weight per shoot was closely related to the number of expanding leaves and was greater in B3L than B1L and B2L, and also greater in summer and autumn than in spring, whereas B1L revealed the greatest young shoot density and highest N concentration. Annual shoot yield and shoot N content were largest in B3L and decreased in the following order: B3L > B2L ≈ B1L/B3L > B1L. However, in the early spring the shoot density, yield, and shoot N content of B1L were much higher than those of B3L. The harvest of B3L significantly reduced the biomass of brown roots and its ratio against the above-ground biomass compared to other harvest standards, suggesting a decreased allocation of carbon to the root system due to seasonal removal. The N dilution curve (N_ys = a × Y_ys^b, where N_ys is the shoot N content and Y_ys is the shoot yield) of spring tea differed markedly from those of summer and autumn teas, suggesting different coordination properties for shoot growth and N supply among the seasons. The annual harvest index (NHI) measured by ¹⁵N traces ranged between 0.18 and 0.23, indicating relatively low N allocation to young shoots, whereby large proportions (58.2–66.9% of the total ¹⁵N absorption) remained in the plant at the end of the experiment. In conclusion, the seasonal distribution of the shoot density, weight per shoot, yield, and N demands vary with harvest standards and highlight the importance of N precision management in tea production to be finely tuned to meet the changes in harvest season and requirements. Full article

(This article belongs to the Special Issue Advances in Tea Plant Biology and Tea Quality Regulation)

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18 pages, 1083 KiB

Open AccessEditor’s ChoiceArticle

Converting Apple Textural Parameters Obtained from Penetrometers and Their Relationships with Sensory Attributes

by Masoumeh Bejaei

Horticulturae 2022, 8(3), 269; https://doi.org/10.3390/horticulturae8030269 - 20 Mar 2022

Cited by 1 | Viewed by 2770

Abstract

Textural attributes of apple impact consumers’ acceptance of the fruit, and are frequently measured by researchers and industry experts to evaluate the fruit quality at different stages of production and marketing. Various instruments are used to conduct these textural evaluations in research and [...] Read more.

Textural attributes of apple impact consumers’ acceptance of the fruit, and are frequently measured by researchers and industry experts to evaluate the fruit quality at different stages of production and marketing. Various instruments are used to conduct these textural evaluations in research and industry settings. The application of different instruments makes the comparison and integration of results extremely difficult. The main objectives of this study were to compare data obtained from three widely used textural instruments, investigate their relationships with each other and with sensory evaluations, and develop models to convert data among instruments. Three penetrometers were included in the study: (1) Fruit Texture Analyzer (FTA); (2) Mohr Digi-Test-2 (MDT-2); and (3) TA.XTplus Texture Analyzer (TA.XTplus). Eight apple varieties with a range of textural attributes were selected. Eleven sensory judges evaluated three apple slices (1/8 apple) from each variety. The instrumental measurements were conducted on 10 apples per instrument from each variety, with two measurements on each apple. Results of principal component analysis indicated that 95.82% of the variation in the texture data could be explained using only two principal components. Linear and nonlinear regression models were developed to convert data obtained from an instrument to those from other instruments. Full article

(This article belongs to the Section Postharvest Biology, Quality, Safety, and Technology)

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16 pages, 1803 KiB

Open AccessEditor’s ChoiceArticle

Integrative Effects of CO₂ Concentration, Illumination Intensity and Air Speed on the Growth, Gas Exchange and Light Use Efficiency of Lettuce Plants Grown under Artificial Lighting

by Hesham A. Ahmed, Yuxin Tong, Lie Li, Suliaman Q. Sahari, Abdulkarem M. Almogahed and Ruifeng Cheng

Horticulturae 2022, 8(3), 270; https://doi.org/10.3390/horticulturae8030270 - 20 Mar 2022

Cited by 8 | Viewed by 3730

Abstract

This study investigates and quantifies the integrative effects of CO₂ concentration (500, 1000 and 1500 µmol mol⁻¹), illumination intensity (100, 200 and 300 μmol m⁻² s⁻¹) and air speed (0.25, 0.50 and 0.75 m s⁻¹) [...] Read more.

This study investigates and quantifies the integrative effects of CO₂ concentration (500, 1000 and 1500 µmol mol⁻¹), illumination intensity (100, 200 and 300 μmol m⁻² s⁻¹) and air speed (0.25, 0.50 and 0.75 m s⁻¹) on the growth, gas exchange and light use efficiency of lettuce plants (Lactuca sativa L.) grown under artificial lighting. The results show that lettuce growth and gas exchange are closely related to CO₂ concentration and illumination intensity, while air speed enhances CO₂ transport during photosynthesis. The most influential two-way interactions were observed between CO₂ concentration and illumination intensity on the fresh and dry weights of lettuce shoots with effect sizes of 34% and 32%, respectively, and on the photosynthesis, transpiration and light use efficiency, with effect sizes of 52%, 47% and 41%, respectively. The most significant three-way interaction was observed for the photosynthetic rate, with an effect size of 51%. In general, the fresh and dry weights of lettuce plants increased by 36.2% and 20.1%, respectively, with an increase in CO₂ concentration from 500 to 1500 µmol mol⁻¹ and by 48.9% and 58.6%, respectively, with an increase in illumination intensity from 100 to 300 μmol m⁻² s⁻¹. The photosynthetic rate was found to be positively correlated with CO₂ concentration, illumination intensity and air speed. The transpiration rate and stomatal conductance increased by 34.9% and 42.1%, respectively, when the illumination intensity increased from 100 to 300 μmol m⁻² s⁻¹. However, as CO₂ concentration increased from 500 to 1500 μmol mol⁻¹ and air speed increased from 0.25 to 0.75 m s⁻¹, the transpiration rate decreased by 17.5% and 12.8%, respectively. With the quantified data obtained, we were able to adequately determine how CO₂ concentration, illumination intensity and air speed interact with their combined effects on the growth of lettuce plants grown in indoor cultivation systems with artificial lighting. Full article

(This article belongs to the Section Vegetable Production Systems)

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20 pages, 5053 KiB

Open AccessEditor’s ChoiceArticle

VIS-NIR Modeling of Hydrangenol and Phyllodulcin Contents in Tea-Hortensia (Hydrangea macrophylla subsp. serrata)

by Marcel Dieter Moll, Liane Kahlert, Egon Gross, Esther-Corinna Schwarze, Maria Blings, Silke Hillebrand, Jakob Ley, Thorsten Kraska and Ralf Pude

Horticulturae 2022, 8(3), 264; https://doi.org/10.3390/horticulturae8030264 - 18 Mar 2022

Cited by 3 | Viewed by 2683

Abstract

Hyperspectral data are commonly used for the fast and inexpensive quantification of plant constituent estimation and quality control as well as in research and development applications. Based on chemical analysis, different models for dihydroisocoumarins (DHCs), namely hydrangenol (HG) and phyllodulcin (PD), were built [...] Read more.

Hyperspectral data are commonly used for the fast and inexpensive quantification of plant constituent estimation and quality control as well as in research and development applications. Based on chemical analysis, different models for dihydroisocoumarins (DHCs), namely hydrangenol (HG) and phyllodulcin (PD), were built using a partial least squares regression (PLSR). While HG is common in Hydrangea macrophylla, PD only occurs in cultivars of Hydrangea macrophylla subsp. serrata, also known as ‘tea-hortensia’. PD content varies significantly over the course of the growing period. For maximizing yield, a targeted estimation of PD content is needed. Nowadays, DHC contents are determined via UPLC, a time-consuming and a destructive method. In this research article we investigated PLSR-based models for HG and PD using three different spectrometers. Two separate trials were conducted to test for model quality. Measurement conditions, namely fresh or dried leaves and black or white background, did not influence model quality. While highly accurate modeling of HG and PD for single plants was not possible, the determination of the mean content on a larger scale was successful. The results of this study show that hyperspectral modeling as a decision support for farmers is feasible and provides accurate results on a field scale. Full article

(This article belongs to the Special Issue Botany, Phytochemistry and Pharmacology in Traditional Herbal Medicine)

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16 pages, 3090 KiB

Open AccessEditor’s ChoiceArticle

Commercial Potato Cultivars Exhibit Distinct Susceptibility to the Root Lesion Nematode Pratylenchus penetrans

by Joana Figueiredo, Paulo Vieira, Isabel Abrantes and Ivânia Esteves

Horticulturae 2022, 8(3), 244; https://doi.org/10.3390/horticulturae8030244 - 12 Mar 2022

Cited by 3 | Viewed by 2950

Abstract

The root lesion nematode Pratylenchus penetrans is an important plant-parasitic nematode of potato. In this study, the susceptibility of commercial potato cultivars to P. penetrans was assessed. Nematode penetration was evaluated in cultivars Agria, Camel, Kennebec, Laura, Royata, and Stemster at 1, 3, [...] Read more.

The root lesion nematode Pratylenchus penetrans is an important plant-parasitic nematode of potato. In this study, the susceptibility of commercial potato cultivars to P. penetrans was assessed. Nematode penetration was evaluated in cultivars Agria, Camel, Kennebec, Laura, Royata, and Stemster at 1, 3, 7, and 15 days after inoculation (DAI) with 750 nematodes/plant, and an egression assay at 3 DAI with 1000 nematodes/plant. Reproduction assays of cultivars Agata, Agria, Camel, Désirée, Dirosso, Kennebec, Laura, Picasso, Royata, and Stemster were performed in 2 L pots inoculated with four P. penetrans/g soil and quantified at 60 DAI. Tenue or moderate root cell browning to advanced necrotic areas were observed after nematode penetration, and the number of nematodes/g of root gradually increased with time of infection. A lower number of deposited eggs and nematodes were observed within the roots of cultivar Laura in all assays comparatively to other cultivars. The susceptibility index (SI) was significantly lower in cultivar Laura (0.4–0.6), followed by cultivars Camel and Picasso (0.8–0.9). All remaining cultivars showed SI values above 1. Although the potato susceptibility to the nematode varied among cultivars, no differences on the average number or weight of tubers produced by each plant of inoculated versus non-inoculated plants were detected. Our data reveals that these cultivars have a distinct ability to support the reproduction of P. penetrans. Full article

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15 pages, 2364 KiB

Open AccessEditor’s ChoiceArticle

A Multicultivar Approach for Grape Bunch Weight Estimation Using Image Analysis

by Gonçalo Victorino, Carlos Poblete-Echeverría and Carlos M. Lopes

Horticulturae 2022, 8(3), 233; https://doi.org/10.3390/horticulturae8030233 - 8 Mar 2022

Cited by 3 | Viewed by 2969

Abstract

The determination of bunch features that are relevant for bunch weight estimation is an important step in automatic vineyard yield estimation using image analysis. The conversion of 2D image features into mass can be highly dependent on grapevine cultivar, as the bunch morphology [...] Read more.

The determination of bunch features that are relevant for bunch weight estimation is an important step in automatic vineyard yield estimation using image analysis. The conversion of 2D image features into mass can be highly dependent on grapevine cultivar, as the bunch morphology varies greatly. This paper aims to explore the relationships between bunch weight and bunch features obtained from image analysis considering a multicultivar approach. A set of 192 bunches from four cultivars, collected at sites located in Portugal and South Africa, were imaged using a conventional digital RGB camera, followed by image analysis, where several bunch features were extracted, along with physical measurements performed in laboratory conditions. Image data features were explored as predictors of bunch weight, individually and in a multiple stepwise regression analysis, which were then tested on 37% of the data. The results show that the variables bunch area and visible berries are good predictors of bunch weight (R² ranging from 0.72 to 0.90); however, the simple regression lines fitted between these predictors and the response variable presented significantly different slopes among cultivars, indicating cultivar dependency. The elected multiple regression model used a combination of four variables: bunch area, bunch perimeter, visible berry number, and average berry area. The regression analysis between the actual and estimated bunch weight yielded a R² = 0.91 on the test set. Our results are an important step towards automatic yield estimation in the vineyard, as they increase the possibility of applying image-based approaches using a generalized model, independent of the cultivar. Full article

(This article belongs to the Special Issue Advances in Viticulture Production)

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13 pages, 2250 KiB

Open AccessEditor’s ChoiceArticle

Decreased Solution pH and Increased K⁺ Uptake Are Related to Ammonium Tolerance in Hydroponically Cultured Plants

by Jinnan Song, Jingli Yang and Byoung Ryong Jeong

Horticulturae 2022, 8(3), 228; https://doi.org/10.3390/horticulturae8030228 - 7 Mar 2022

Cited by 6 | Viewed by 2708

Abstract

The ammonium (NH₄⁺) tolerance of plants is an important issue in agriculture, associated with several plant characteristics. So far, plant tissue acidification has been shown as the primary cause of NH₄⁺ toxicity. Suppressed plant growth caused by excess [...] Read more.

The ammonium (NH₄⁺) tolerance of plants is an important issue in agriculture, associated with several plant characteristics. So far, plant tissue acidification has been shown as the primary cause of NH₄⁺ toxicity. Suppressed plant growth caused by excess NH₄⁺ can be counteracted by potassium (K⁺) application. However, the effects of NH₄⁺ tolerances on the differences regarding pH changes together with K⁺ uptake remain to be determined. Here, we performed an 84 h hydroponic cultivation of five species with different NH₄⁺ tolerances, subjected to three NH₄⁺:NO₃⁻ solutions (0:100, 50:50, or 100:0), to investigate the pH changes and ion uptakes. Consequently, the solution pH was lowered over time to varying extents in the presence of NH₄⁺. The NH₄⁺-tolerant ageratum and lettuce, shown to be tolerant to NH₄⁺ in this trial, rapidly lowered the solution pH, whereas extremely NH₄⁺-sensitive salvia and cabbage only gave a minor decrease in the solution pH when grown with 100:0 NH₄⁺:NO₃⁻. Additionally, the increased external NH₄⁺ level led to a substantial decline in the net cation influxes (K⁺, Ca²⁺, and Mg²⁺). As compared to solely NH₄⁺-fed salvia and cabbage, solely NH₄⁺-fed ageratum and lettuce ultimately showed a relatively greater net K⁺ influx. Taken together, this study discusses how the decreases in pH and K⁺ are related to NH₄⁺ tolerance in five hydroponically cultured species. Full article

(This article belongs to the Special Issue Strategies and Practices of Fertilization Management of Horticultural Crops)

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12 pages, 3281 KiB

Open AccessEditor’s ChoiceArticle

Microalga Biofertilizer Triggers Metabolic Changes Improving Onion Growth and Yield

by Ely Cristina Negrelli Cordeiro, Átila Francisco Mógor, Juliana de Oliveira Amatussi, Gilda Mógor, Gabriel Bocchetti de Lara and Harielly Marianne Costa Marques

Horticulturae 2022, 8(3), 223; https://doi.org/10.3390/horticulturae8030223 - 4 Mar 2022

Cited by 5 | Viewed by 2851

Abstract

Seeking the development of nature-friendly agronomic techniques, the use of natural sources to promote plant growth and increase agricultural yield has gained relevance. In this context, the use of biofertilizers or biostimulants obtained from microalgae has been studied, as these microorganisms have in [...] Read more.

Seeking the development of nature-friendly agronomic techniques, the use of natural sources to promote plant growth and increase agricultural yield has gained relevance. In this context, the use of biofertilizers or biostimulants obtained from microalgae has been studied, as these microorganisms have in their composition a great diversity of bioactive molecules. This study aimed to evaluate the effect of microalga Asterarcys quadricellulare (CCAP 294/1) on organic onion production, verifying its action on metabolism, growth and yield of two cultivars. Thus, two experiments were carried out: (i) foliar applications on onion plants grown in pots in a greenhouse; (ii) foliar applications on field-grown onion under an organic system. Both experiments were undertaken using solutions with spray-dried microalga biomass at concentrations of 0.05, 0.15, 0.25 and 0.4 g L⁻¹. Biometric variables, yield of bulbs and biochemical variables were evaluated indicating that the use of A. quadricellulare promoted plant growth and increases in bulb caliber and yield of both onion cultivars. The microalga biomass stimulated plant metabolism by increases in contents of chlorophyll, carotenoids, amino acids, and the nitrate reductase enzyme activity in leaves, also free amino acids and total sugar contents in bulbs, highlighting the biomass concentration of 0.25 g L⁻¹. Full article

(This article belongs to the Section Plant Nutrition)

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14 pages, 1818 KiB

Open AccessEditor’s ChoiceArticle

Optimization of the Yield, Total Phenolic Content, and Antioxidant Capacity of Basil by Controlling the Electrical Conductivity of the Nutrient Solution

by Xiaowei Ren, Na Lu, Wenshuo Xu, Yunfei Zhuang and Michiko Takagaki

Horticulturae 2022, 8(3), 216; https://doi.org/10.3390/horticulturae8030216 - 1 Mar 2022

Cited by 11 | Viewed by 3430

Abstract

Hydroponic cultivation using nutrient solution (NS) is the main cultivation method employed by plant factories with artificial lighting (PFALs). The electrical conductivity (EC) of NSs influences the yield and quality of vegetables. The purpose of this study was to optimize the yield and [...] Read more.

Hydroponic cultivation using nutrient solution (NS) is the main cultivation method employed by plant factories with artificial lighting (PFALs). The electrical conductivity (EC) of NSs influences the yield and quality of vegetables. The purpose of this study was to optimize the yield and antioxidant accumulation of basil in a PFAL by EC management. In experiment 1, basil plants were grown under four different ECs (0.5, 1.0, 3.0, and 5.0 dS m⁻¹) after transplanting. At 18 days after treatment, the highest levels of shoot fresh and dry weights, leaf fresh and dry weights, and leaf area were observed at an EC of 3.0 dS m⁻¹. However, low-EC treatments (0.5 and 1.0 dS m⁻¹) generated total phenolic content (TPC) and antioxidant capacities that were higher than those of other EC treatments (3.0 and 5.0 dS m⁻¹). In experiment 2, basil plants were grown at an EC of 3.0 dS m⁻¹ for 13 or 15 days, then treated with water or NS with low ECs (0.5 and 1.0 dS m⁻¹) for 5 or 3 days before harvest. The short-term low-EC treatments, especially, water for 3 days and 0.5 dS m⁻¹ for 5 days, significantly increased the TPC and antioxidant capacity of leaves without significantly decreasing the yields of basil, compared with the control. In conclusion, yield of basil was optimized with an EC of 3.0 dS m⁻¹; however, the TPC and antioxidant capacity of basil were significantly increased by low ECs of 0.5 and 1.0 dS m⁻¹. Short-term low-EC treatments (0.5 dS m⁻¹ for 5 days or water for 3 days) could be used to promote the TPC and antioxidant capacity in leaves without sacrificing yield of basil significantly. Full article

(This article belongs to the Special Issue Urban Horticulture - New Trends and Technologies)

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20 pages, 7329 KiB

Open AccessEditor’s ChoiceArticle

The Inclusion of Green Light in a Red and Blue Light Background Impact the Growth and Functional Quality of Vegetable and Flower Microgreen Species

by Matteo Orlando, Alice Trivellini, Luca Incrocci, Antonio Ferrante and Anna Mensuali

Horticulturae 2022, 8(3), 217; https://doi.org/10.3390/horticulturae8030217 - 1 Mar 2022

Cited by 19 | Viewed by 7898

Abstract

Microgreens are edible seedlings of vegetables and flowers species which are currently considered among the five most profitable crops globally. Light-emitting diodes (LEDs) have shown great potential for plant growth, development, and synthesis of health-promoting phytochemicals with a more flexible and feasible spectral [...] Read more.

Microgreens are edible seedlings of vegetables and flowers species which are currently considered among the five most profitable crops globally. Light-emitting diodes (LEDs) have shown great potential for plant growth, development, and synthesis of health-promoting phytochemicals with a more flexible and feasible spectral manipulation for microgreen production in indoor farms. However, research on LED lighting spectral manipulation specific to microgreen production, has shown high variability in how these edible seedlings behave regarding their light environmental conditions. Hence, developing species-specific LED light recipes for enhancement of growth and valuable functional compounds is fundamental to improve their production system. In this study, various irradiance levels and wavelengths of light spectrum produced by LEDs were investigated for their effect on growth, yield, and nutritional quality in four vegetables (chicory, green mizuna, china rose radish, and alfalfa) and two flowers (french marigold and celosia) of microgreens species. Microgreens were grown in a controlled environment using sole-source light with different photosynthetic photon flux density (110, 220, 340 µmol m⁻² s⁻¹) and two different spectra (RB: 65% red, 35% blue; RGB: 47% red, 19% green, 34% blue). At harvest, the lowest level of photosynthetically active photon flux (110 µmol m⁻² s⁻¹) reduced growth and decreased the phenolic contents in almost all species. The inclusion of green wavelengths under the highest intensity showed positive effects on phenolic accumulation. Total carotenoid content and antioxidant capacity were in general enhanced by the middle intensity, regardless of spectral combination. Thus, this study indicates that the inclusion of green light at an irradiance level of 340 µmol m⁻² s⁻¹ in the RB light environment promotes the growth (dry weight biomass) and the accumulation of bioactive phytochemicals in the majority of the microgreen species tested. Full article

(This article belongs to the Special Issue Indoor Farming and Artificial Cultivation)

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26 pages, 2798 KiB

Open AccessEditor’s ChoiceReview

Top Ten Most Important U.S.-Regulated and Emerging Plant-Parasitic Nematodes

by Mihail Kantor, Zafar Handoo, Camelia Kantor and Lynn Carta

Horticulturae 2022, 8(3), 208; https://doi.org/10.3390/horticulturae8030208 - 26 Feb 2022

Cited by 25 | Viewed by 7522

Abstract

Plant-parasitic nematodes (PPNs) are important pests that cause an estimated ten billion dollars of crop loss each year in the United States and over 100 billion dollars globally. The Animal and Plant Health Inspection Service (APHIS) within the U.S. Department of Agriculture maintains [...] Read more.

Plant-parasitic nematodes (PPNs) are important pests that cause an estimated ten billion dollars of crop loss each year in the United States and over 100 billion dollars globally. The Animal and Plant Health Inspection Service (APHIS) within the U.S. Department of Agriculture maintains and updates the U.S. Regulated Plant Pest list. Currently, the number of PPNs regulated by APHIS includes more than 60 different species. This review focuses on the top ten most economically important regulated and emerging plant-parasitic nematodes and summarizes the diagnostics of morphological and some molecular features for distinguishing them. These ten major previously described nematode species are associated with various economically important crops from around the world. This review also includes their current distribution in the U.S. and a brief historical background and updated systematic position of these species. The species included in this review include three PPNs considered by the U.S. Department of Agriculture as invasive invertebrates Globodera pallida, Globodera rostochiensis, and Heterodera glycines; four regulated PPNs, namely Bursaphelenchus xylophilus, Meloidogyne fallax, Ditylenchus dipsaci, and Pratylenchus fallax; and the three emerging PPNs Meloidogyne chitwoodi, Meloidogyne enterolobii, and Litylenchus crenatae mccannii. Full article

(This article belongs to the Special Issue Recent Advance in the Identification and Diagnostics of Plant-Parasitic Nematodes)

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10 pages, 2200 KiB

Open AccessEditor’s ChoiceArticle

Shoot Development through Modified Transverse Thin Cell Layer (tTCL) Culture of Phalaenopsis Hybrid Protocorms

by Kuo-Chin Lo, Jualang Azlan Gansau, Chia-Hung Shih and Chien-Yuan Kao

Horticulturae 2022, 8(3), 206; https://doi.org/10.3390/horticulturae8030206 - 26 Feb 2022

Cited by 5 | Viewed by 2881

Abstract

This first-attempt study used microtome-based methods to generate a thin cell layer culture for the micropropagation of Phal. Hwafeng Redjewel × Phal. New Cinderella. Protocorms were embedded in various agarose concentrations (8–12%, w/v) and dried from 1 to 8 h [...] Read more.

This first-attempt study used microtome-based methods to generate a thin cell layer culture for the micropropagation of Phal. Hwafeng Redjewel × Phal. New Cinderella. Protocorms were embedded in various agarose concentrations (8–12%, w/v) and dried from 1 to 8 h before sectioning with a microtome. Optimal conditions for slicing sections of 100 to 300 μm were achieved when the protocorms were embedded at 10% (w/v) agarose and dried for 4 h under laminar flow, and the hardness of the agarose block under these conditions reached 641.8 ± 9.5 g·cm⁻². The sectioned protocorms that were cultured on an MS medium supplemented with 1.2 mg·L⁻¹ 6-benzylaminopurine and 0.1 mg·L⁻¹ α-naphthaleneacetic acid were capable of growth and differentiated through the neoformation of protocorm-like bodies (PLBs) and/or callus before subsequent regeneration into plantlets and development into healthy plants in a nursery environment. The results of this study demonstrate that microtome-based tTCL is a reliable and promising approach for mass propagation and possible virus-free propagation objectives for Phalaenopsis. Full article

(This article belongs to the Special Issue Advances in Orchid Physiology, Micropropagation, Breeding and Genomics)

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13 pages, 1818 KiB

Open AccessEditor’s ChoiceArticle

Effect of Chitosan-Poly(Acrylic Acid) Complexes and Two Nutrient Solutions on the Growth and Yield of Two Habanero Pepper Cultivars

by Rogelio Enrique Palacios-Torres, Amadeo Santos-Chavez, Hortensia Ortega-Ortiz, Ana Rosa Ramírez-Seañez, José Antonio Yam-Tzec, Adolfo Amador-Mendoza, Antonio Juárez-Maldonado, Maribel Reyes-Osornio and Hipólito Hernández-Hernández

Horticulturae 2022, 8(3), 201; https://doi.org/10.3390/horticulturae8030201 - 24 Feb 2022

Cited by 4 | Viewed by 2376

Abstract

Chitosan (CS) is a natural polymer used in agriculture as a biostimulant that has been evaluated in different plant models. In this study, we evaluated the effect of the foliar application of chitosan–poly(acrylic acid) complexes (CS–PAA) and two nutrient solutions (A and B) [...] Read more.

Chitosan (CS) is a natural polymer used in agriculture as a biostimulant that has been evaluated in different plant models. In this study, we evaluated the effect of the foliar application of chitosan–poly(acrylic acid) complexes (CS–PAA) and two nutrient solutions (A and B) on the parameters of growth and yield of two habanero pepper cultivars (Chichen Itza and Jaguar) in a greenhouse. Over the course of the experiment, eight foliar applications were carried out at 15-day intervals. Our results showed that foliar applications of CS–PAA complexes have a biostimulant effect on the habanero pepper crop by increasing the total dry biomass of the plant and the number of fruits of the two cultivars. Regarding nutrient solutions, the nutrient solution A increased the yield of the Chichen Itza cultivar; this effect was because it had a better balance of potassium and calcium compared to the nutrient solution B. These results provide advances on the use of CS–PAA complexes as a biostimulant and the management of nutrient solutions in the crop of habanero peppers. Full article

(This article belongs to the Special Issue Hydroponics in Vegetable Production)

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17 pages, 4356 KiB

Open AccessEditor’s ChoiceArticle

Research on Mixing Law of Liquid Fertilizer Injected into Irrigation Pipe

by Zhiyang Zhang, Chao Chen, Hong Li and Pan Tang

Horticulturae 2022, 8(3), 200; https://doi.org/10.3390/horticulturae8030200 - 24 Feb 2022

Cited by 6 | Viewed by 2632

Abstract

The time and position that fertilizer takes to uniformly mix with water in an irrigation system significantly affects the development of a fertilization strategy. A pipe irrigation system was used to study the fertilizer–water mixing law in irrigation pipes using numerical simulation and [...] Read more.

The time and position that fertilizer takes to uniformly mix with water in an irrigation system significantly affects the development of a fertilization strategy. A pipe irrigation system was used to study the fertilizer–water mixing law in irrigation pipes using numerical simulation and experiments. The effect of the diameter of the water pipe and fertilizer pipe, water and fertilizer flow rates, concentration and viscosity of fertilizer, frequency of fertilizer injection on the mixing speed, and uniform mixing length indicated that the frequency of fertilizer injection did not affect the mixing process. The increase in the water pipe diameter and fertilizer flow rate or the decrease in fertilizer pipe and water flow rate diameter result in the increase of the speed of fertilizer solution mixing with water along the radial direction of the mixing pipe. The uniform mixing length was directly proportional to the fertilizer pipe diameter, water pipe diameter, water flow rate, and fertilizer viscosity, while it was inversely proportional to the flow rate and concentration of fertilizer. The relationship between the uniform mixing length and six influencing factors was fitted, the fitting was highly accurate, and the fitting equation can be used to predict the uniform mixing length under other conditions. Full article

(This article belongs to the Special Issue Advanced of Horticulture Innovative Irrigation Technologies)

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13 pages, 2370 KiB

Open AccessEditor’s ChoiceArticle

Nutrient Uptake and Yield of Chinese Cabbage (Brassica rapa L. Chinensis) Increased with Application of Macadamia Husk Compost

by Dembe Maselesele, John B. O. Ogola and Romeo N. Murovhi

Horticulturae 2022, 8(3), 196; https://doi.org/10.3390/horticulturae8030196 - 23 Feb 2022

Cited by 5 | Viewed by 5302

Abstract

There is a dearth of information on the effect of macadamia husk compost (MHC) on the productivity of short-season, shallow-rooted annual crops. We assessed the response of yield and nutrient uptake of Chinese cabbage (Brassica rapa L. Chinensis) to MHC application. [...] Read more.

There is a dearth of information on the effect of macadamia husk compost (MHC) on the productivity of short-season, shallow-rooted annual crops. We assessed the response of yield and nutrient uptake of Chinese cabbage (Brassica rapa L. Chinensis) to MHC application. The treatments (zero control, inorganic fertilizer (100:60:60 kg NPK ha⁻¹), and 15 and 30 t ha⁻¹ MHC) were arranged in a randomized complete block design and replicated three times. Number of leaves, leaf area index, leaf biomass, and leaf nutrient concentration (N, P, K, Ca, Mg, Zn, Cu, Mn, and B) were determined at 28, 46, and 74 days after transplanting (DAT), and root length and root biomass were determined at 74 DAT. Inorganic fertilizer and MHC increased root biomass and root length with greater increases recorded at the higher MHC rates. Number of leaves, leaf area index, leaf biomass, and nutrient concentration were greater with application of inorganic fertilizer (28 DAT) and 30 t ha⁻¹ (74 DAT) suggesting that the effect of organic soil amendments is more pronounced over the long run compared with inorganic fertilizers. The concentration of macronutrients in the leaf increased with application of MHC and inorganic fertilizer. Clearly, MHC may be beneficial in improving the leaf yield and nutrient uptake of Chinese cabbage in a loamy sand soil, but the effect varies with time of harvesting. Full article

(This article belongs to the Special Issue Recent Advances in Nutrition and Fertilization of Horticultural Crops)

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17 pages, 3489 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Grapevine Response to Stress Generated by Excessive Temperatures during the Budburst

by Sergio Tombesi, Paolo Sabbatini, Tommaso Frioni, Francesca Grisafi, Federico Barone, Paolo Zani, Alberto Palliotti and Stefano Poni

Horticulturae 2022, 8(3), 187; https://doi.org/10.3390/horticulturae8030187 - 22 Feb 2022

Cited by 4 | Viewed by 2674

Abstract

At springtime, the formation of stem somatic traits (stem elongation and leaf growth) and reproductive activity (flowering and fruit set) occur simultaneously. They are all competing carbon sinks, with an extremely high demand for carbohydrates. The shoot growth rate is strongly related to [...] Read more.

At springtime, the formation of stem somatic traits (stem elongation and leaf growth) and reproductive activity (flowering and fruit set) occur simultaneously. They are all competing carbon sinks, with an extremely high demand for carbohydrates. The shoot growth rate is strongly related to environmental temperature, which, according to climate change scenarios, is expected to increase also in extremes. Our hypothesis was that the increase in temperature during budburst could increase the vegetative carbon sink strength reducing the carbon stock available for the reproductive activity jeopardizing flowering of the next year. In our experiment, we artificially conditioned grapevine budburst by exposing the growing shoots to different temperature regimes. Higher temperatures during the spring vegetative growth favored shoot stem extension at the detriment of shoot leaf area. This caused a reduction in vine CO₂ assimilation, which, combined with the competition of the growing vegetative organs, affected the concurrent reproductive activity, with carry-over effects on the following year, resulting in a limited flower initiation in dormant buds. These results suggest that the increase in springtime temperature can alter canopy development and vine physiology, resulting in the reduction in reproductive activity with an economical negative impact on grapevine productivity. Full article

(This article belongs to the Section Viticulture)

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13 pages, 922 KiB

Open AccessEditor’s ChoiceArticle

Graded Moisture Deficit Effect on Secondary Metabolites, Antioxidant, and Inhibitory Enzyme Activities in Leaf Extracts of Rosa damascena Mill. var. trigentipetala

by Kamel Hessini, Hanen Wasli, Hatim M. Al-Yasi, Esmat F. Ali, Ahmed A. Issa, Fahmy A. S. Hassan and Kadambot H. M. Siddique

Horticulturae 2022, 8(2), 177; https://doi.org/10.3390/horticulturae8020177 - 21 Feb 2022

Cited by 29 | Viewed by 2718

Abstract

Drought affects plant growth and yield in many agricultural areas worldwide by producing negative water potentials in the root zone that reduce water availability, affecting plant development and metabolism. This study investigated the effect of varying moisture regimes (100% field capacity (FC), well-watered [...] Read more.

Drought affects plant growth and yield in many agricultural areas worldwide by producing negative water potentials in the root zone that reduce water availability, affecting plant development and metabolism. This study investigated the effect of varying moisture regimes (100% field capacity (FC), well-watered plants, 50% FC (moderate water stress), and 25% FC (severe water stress)) on growth parameters, chlorophyll content, and bioactive molecule patterns, and the impact on antioxidant, lipoxygenase (LOX), and acetylcholinesterase (AChE) activities in Rosa damascena. The water deficit treatments reduced biomass production for both treatments (−29 and −33%, respectively, for MWS and SWS) and total chlorophyll (−18 and −38% respectively for MWS and SWS), relative to the control. The 50% FC treatment had the greatest effect on the phenolic profiles and their respective functionalities, with significant increases in the levels of total phenolic, benzoic (gallic, p-coumaric, and syringic acids) (+32%), and cinnamic (caffeic and trans-cinnamic acid) acids (+19%) and flavonoids (epicatechin-3-O-gallate) (+15%) compared to well-watered leaves (control leaves). The 50% FC treatment also exhibited the highest potential antioxidant activities (apart from NO-quenching activity), evidenced by the lowest IC₅₀ and EC₅₀ values. The inhibitory LOX and AChE capacities varied depending on the severity of stress, with superior activity in the 50% FC treatment. Overall, the drought tolerance in rose was associated mainly with its suitable manipulation of antioxidant production and orderly regulation of LOX and AChE activities. Full article

(This article belongs to the Special Issue Drought Stress in Horticultural Plants)

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11 pages, 9741 KiB

Open AccessEditor’s ChoiceArticle

Effects of Light Intensity and Temperature on the Photosynthesis Characteristics and Yield of Lettuce

by Jing Zhou, Pingping Li and Jizhang Wang

Horticulturae 2022, 8(2), 178; https://doi.org/10.3390/horticulturae8020178 - 21 Feb 2022

Cited by 41 | Viewed by 15264

Abstract

Lettuce is an important vegetable in horticulture, but information about the interactive effects of light and temperature on its photosynthetic characteristics was inadequate. This work investigated the effects of three temperatures (15/10 (T15), 23/18 (T23), and 30/23 °C (T30)) and five light treatments [...] Read more.

Lettuce is an important vegetable in horticulture, but information about the interactive effects of light and temperature on its photosynthetic characteristics was inadequate. This work investigated the effects of three temperatures (15/10 (T15), 23/18 (T23), and 30/23 °C (T30)) and five light treatments (100 (P100), 200 (P200), 350 (P350), 500 (P500), and 600 μmol·m⁻²·s⁻¹ (P600)) on the light–response curves, chlorophyll content, and yield of lettuce. The results showed that the maximum photosynthetic rate, light saturation point, chlorophyll content, and yield of lettuce were all the highest at T23 compared with T15 and T30 under different light intensities. Under the same temperature conditions, the photosynthesis capacity and yield of lettuce in the P350 and P500 treatments at T15, P350, P500, and P600 treatments at T23 and P500, and P600 treatments at T30 were larger than other light treatments. The results suggested that temperature play had a more pronounced influence on photosynthesis and yield in lettuce, but the appropriate levels of light intensity improved its potential photosynthetic capacity and yield under different temperature conditions. Full article

(This article belongs to the Section Developmental Physiology, Biochemistry, and Molecular Biology)

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20 pages, 3619 KiB

Open AccessEditor’s ChoiceArticle

Response of Tomato-Pseudomonas Pathosystem to Mild Heat Stress

by Loredana Scalschi, Emma Fernández-Crespo, Marcel Pitarch-Marin, Eugenio Llorens, Ana Isabel González-Hernández, Gemma Camañes, Begonya Vicedo and Pilar García-Agustín

Horticulturae 2022, 8(2), 174; https://doi.org/10.3390/horticulturae8020174 - 20 Feb 2022

Cited by 3 | Viewed by 2292

Abstract

Higher plants suffer from mild heat stress when temperatures increase by 5 °C above optimum growth temperatures. This produces changes at the cellular and metabolic levels, allowing plants to adapt to heat conditions. This study investigated an increase of 5 °C above the [...] Read more.

Higher plants suffer from mild heat stress when temperatures increase by 5 °C above optimum growth temperatures. This produces changes at the cellular and metabolic levels, allowing plants to adapt to heat conditions. This study investigated an increase of 5 °C above the optimum growth temperature (26 °C) of tomato plants in the tomato—Pseudomonas syringae pv. tomato pathosystem. A temperature increase above 26 °C affects plant development, the defensive pathways activated against Pseudomonas syringae pv. tomato strain DC3000 (PstDC3000), and the bacterial growth and virulence machinery. The results demonstrated that tomato plants were able to acclimate to mild heat stress, showing no symptoms of damage. Moreover, plants subjected to a 5 °C increase (T31 °C plants) showed higher basal levels of metabolites such as proline and putrescine, which probably act as compatible osmolytes. This demonstrates their importance as key components of thermotolerance. When grown under mild heat stress, plants were less susceptible to PstDC3000 and showed increased accumulation of abscisic acid, jasmonic acid-isoleucine, and spermine. In addition, the temperature increase negatively affected the infectivity of PstDC3000. Inhibition of the genes responsible for quorum sensing establishment and synthesis of flagellin and coronatine was observed in bacteria extracted from T31 °C plants. Analysis of the genes involved in the synthesis of the type III secretion system indicates the important role of this system in bacterial growth under these conditions. As the known resistance mechanisms involved in the defense against PstDC3000 were not activated, the changes in its virulence mechanisms under high temperatures may explain the lower infection observed in the T31 °C plants. Full article

(This article belongs to the Special Issue Host-Pathogen Interaction in Climate Change Scenario)

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20 pages, 2290 KiB

Open AccessEditor’s ChoiceReview

Molecular and Metabolic Changes under Environmental Stresses: The Biosynthesis of Quality Components in Preharvest Tea Shoots

by Jianjun Liu, Beibei Wen, Xiaobo Liu, Yun Yang, Meifeng Li and Xiaojing Wang

Horticulturae 2022, 8(2), 173; https://doi.org/10.3390/horticulturae8020173 - 19 Feb 2022

Cited by 4 | Viewed by 2852

Abstract

Severe environments impose various abiotic stresses on tea plants. Although much is known about the physiological and biochemical responses of tea (Camellia sinensis L.) shoots under environmental stresses, little is known about how these stresses impact the biosynthesis of quality components. This [...] Read more.

Severe environments impose various abiotic stresses on tea plants. Although much is known about the physiological and biochemical responses of tea (Camellia sinensis L.) shoots under environmental stresses, little is known about how these stresses impact the biosynthesis of quality components. This review summarizes and analyzes the changes in molecular and quality components in tea shoots subjected to major environmental stresses during the past 20 years, including light (shade, blue light, green light, and UV-B), drought, high/low temperature, CO₂, and salinity. These studies reveal that carbon and nitrogen metabolism is critical to the downstream biosynthesis of quality components. Based on the molecular responses of tea plants to stresses, a series of artificial methods have been suggested to treat the pre-harvest tea plants that are exposed to inhospitable environments to improve the quality components in shoots. Furthermore, many pleiotropic genes that are up- or down-regulated under both single and concurrent stresses were analyzed as the most effective genes for regulating multi-resistance and quality components. These findings deepen our understanding of how environmental stresses affect the quality components of tea, providing novel insights into strategies for balancing plant resistance, growth, and quality components in field-based cultivation and for breeding plants using pleiotropic genes. Full article

(This article belongs to the Collection The Correlation of Stress Response and Organ Development in Horticultural Crops)

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10 pages, 906 KiB

Open AccessEditor’s ChoiceArticle

Identification of Suitable Reference Genes for qRT-PCR Normalization in Kiwifruit

by Yuanjie Zhou, Hui Xia, Xinling Liu, Zhiyi Lin, Yuqi Guo, Honghong Deng, Jin Wang, Lijin Lin, Qunxian Deng, Xiulan Lv, Kunfu Xu and Dong Liang

Horticulturae 2022, 8(2), 170; https://doi.org/10.3390/horticulturae8020170 - 18 Feb 2022

Cited by 7 | Viewed by 2479

Abstract

Reference genes are used for the correction of qRT-PCR data, and it is necessary to investigate the optimum reference gene under certain conditions. The expression levels of seven traditional reference genes ACT1, ACT2, GAPDH, 18S rRNA, UBQ, TUB [...] Read more.

Reference genes are used for the correction of qRT-PCR data, and it is necessary to investigate the optimum reference gene under certain conditions. The expression levels of seven traditional reference genes ACT1, ACT2, GAPDH, 18S rRNA, UBQ, TUB and CYP were analyzed using qRT-PCR in different varieties, tissues, developmental stages and hormone (or pollen polysaccharide) treatments in kiwifruit. Gene expression stability was assessed with the help of three common software (geNorm, NormFinder, BestKeeper), and the minimum number of reference genes necessary for normalization was also determined. GAPDH, ACT1 and ACT2 were selected as reference genes for different genotypes of kiwifruit. GAPDH and UBQ were the best combinations of reference genes for root, stem, leaf, flower and fruit. GAPDH and ACT1 could be the preferred reference genes for normalization of qRT-PCR data during fruit development. The pairing of ACT1 and UBQ constituted the optimal combination of reference genes in kiwifruit treated with different hormones (or pollen polysaccharide). This study provides a new and reliable option for the use of reference genes in the analysis of gene expression patterns of interest in kiwifruit. Full article

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16 pages, 3944 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Metabolic Profiling of Organic Acids Reveals the Involvement of HuIPMS2 in Citramalic Acid Synthesis in Pitaya

by Jiaxuan Chen, Yuanju Yuan, Fangfang Xie, Zhike Zhang, Jianye Chen, Rong Zhang, Jietang Zhao, Guibing Hu and Yonghua Qin

Horticulturae 2022, 8(2), 167; https://doi.org/10.3390/horticulturae8020167 - 16 Feb 2022

Cited by 3 | Viewed by 2665

Abstract

Pitayas are rich in organic acids, especially citramalic acid, which is significantly higher than the plants. However, the mechanism of citramalic acid biosynthesis remains to be fully elucidated. In this study, organic acid compositions and contents, as well as expression patterns of key [...] Read more.

Pitayas are rich in organic acids, especially citramalic acid, which is significantly higher than the plants. However, the mechanism of citramalic acid biosynthesis remains to be fully elucidated. In this study, organic acid compositions and contents, as well as expression patterns of key genes related to organic acid metabolism were analyzed during fruit maturation of four different pitaya cultivars i.e., ‘Guanhuabai’ (GHB), ‘Guanhuahong’ (GHH), ‘Wucihuanglong’ (WCHL), and ‘Youcihuanglong’ (YCHL). The total organic acid contents increased first and then declined during fruit maturation. The main organic acids were citramalic acid during the early stages of GHB, GHH, and WCHL pitayas, and dominated by malic acid as fruit maturation. In comparison, citric acid and malic acid were main organic acid for ‘YCHL’ pitaya. Citramalate synthase (IPMS) was involved in the synthesis of citramalic acid, and three types of HuIPMS i.e., HuIPMS1, HuIPMS2, and HuIPMS3, were obtained in our study. Highest expression levels of HuIPMS1 were detected in sepals, while HuIPMS2 and HuIPMS3 exhibited preferential expression in tender stems and ovaries. The expression levels of HuIPMS2 and HuIPMS3 were positively correlated with the content of citramalic acid in the four pitaya cultivars. HuIPMS2 was a chloroplast-localized protein, while HuIPMS3 presented a cytoplasmic-like and nuclear subcellular localization. These findings provide an important basis for further understanding of the molecular mechanism that leads to citramalic acid metabolism during pitaya fruit maturation. Full article

(This article belongs to the Collection Advances in Fruit Quality Formation and Regulation)

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20 pages, 9210 KiB

Open AccessEditor’s ChoiceReview

Volatile Organic Compounds from Basil Essential Oils: Plant Taxonomy, Biological Activities, and Their Applications in Tropical Fruit Productions

by Tibet Tangpao, Nutthawut Charoimek, Patipon Teerakitchotikan, Noppol Leksawasdi, Kittisak Jantanasakulwong, Pornchai Rachtanapun, Phisit Seesuriyachan, Yuthana Phimolsiripol, Thanongsak Chaiyaso, Warintorn Ruksiriwanich, Pensak Jantrawut, Hien Van Doan, Ratchadawan Cheewangkoon and Sarana Rose Sommano

Horticulturae 2022, 8(2), 144; https://doi.org/10.3390/horticulturae8020144 - 8 Feb 2022

Cited by 20 | Viewed by 10145

Abstract

Basils of the genus Ocimum are aromatic plants grown widely throughout the tropical and temperate regions. The essential oils obtained from their aerial parts are enriched with volatile organic compounds with high market demand for food and pharmaceutical industries. The volatile organic compounds [...] Read more.

Basils of the genus Ocimum are aromatic plants grown widely throughout the tropical and temperate regions. The essential oils obtained from their aerial parts are enriched with volatile organic compounds with high market demand for food and pharmaceutical industries. The volatile organic compounds have been shown to exhibit biological activities. Therefore, their novel applications have been extensively explored in the last few decades. The most widely available basils in the tropical areas include white holy basil (O. sanctum var. Shyama), red holy basil (O. sanctum var. Rama), Thai basil (O. basilicum var. thyrsiflorum), lemon basil (O. citriodorum), and tree basil (O. gratissimum). Over 60 volatiles of different classes have been exclusively described, and some of them could be useful as biomarkers for genotype specification. The major volatile ingredient is the phenylpropanoids, such as methyl eugenol, which has the potential as a natural product for mitigating Oriental fruit fly (Bactrocera dorsalis) during tropical fruit production. Moreover, basil essential oils are also used to control diseases of the fruits during post-harvest storage. As a result, the application of basil essential oils as a sustainable defect control strategy for tropical fruit value chains seems intriguing. This review provides comprehensive information on plant taxonomy and volatile compositions of the essential oil fractions from different basil species. Their biological activities and applications are also discussed, mainly during the pre- and post-production of tropical fruits. Additionally, the available techniques to enhance the efficacy of the volatile active compounds are also described. Full article

(This article belongs to the Special Issue Phytochemicals of Natural Products: Analysis and Biological Activities)

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9 pages, 2355 KiB

Open AccessEditor’s ChoiceArticle

Effects of Magnesium Application on Tipburn Incidence and Calcium Acquisition in Lisianthus (Eustoma grandiflorum) Cultivars

by Takanori Kuronuma, Kanami Ishikawa and Hitoshi Watanabe

Horticulturae 2022, 8(2), 132; https://doi.org/10.3390/horticulturae8020132 - 31 Jan 2022

Cited by 1 | Viewed by 2880

Abstract

The occurrence of tipburn is a severe problem in horticulture crop production. A previous study suggested that, in lisianthus, tipburn is caused by imbalanced calcium (Ca) distribution. However, there are few studies on the effects of other cations on tipburn incidence in lisianthus [...] Read more.

The occurrence of tipburn is a severe problem in horticulture crop production. A previous study suggested that, in lisianthus, tipburn is caused by imbalanced calcium (Ca) distribution. However, there are few studies on the effects of other cations on tipburn incidence in lisianthus cultivars. In this study, to determine the effect of Magnesium (Mg) concentration in nutrient solution on tipburn incidence and Ca and Mg acquisition, three lisianthus cultivars (‘Celeb Wine’: CW, ‘Reina White’: RW, and ‘Voyage Peach’: VP) were cultivated under different Mg concentrations in nutrient solution (12 ppm, 34.7 ppm, and 75.4 ppm). Under high nutritional Mg concentrations, CW and RW had significantly decreased tipburn severity, while VP showed no significant differences in tipburn severity among the treatments. Total Ca concentrations in all cultivars significantly increased at higher nutritional Mg concentrations, which indicated that Mg application in lisianthus cultivars promoted Ca acquisition. Furthermore, it was suggested that CW and RW had the ability to distribute increased Mg to the tip of the upper leaves, thereby promoting Ca distribution. Thus, a decrease in tipburn severity in CW and RW at higher nutritional Mg concentrations appeared to occur. Full article

(This article belongs to the Section Plant Nutrition)

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28 pages, 10559 KiB

Open AccessEditor’s ChoiceArticle

Adaptalight: An Inexpensive PAR Sensor System for Daylight Harvesting in a Micro Indoor Smart Hydroponic System

by Joseph D Stevens, David Murray, Dean Diepeveen and Danny Toohey

Horticulturae 2022, 8(2), 105; https://doi.org/10.3390/horticulturae8020105 - 25 Jan 2022

Cited by 10 | Viewed by 4523

Abstract

Environmental changes and the reduction in arable land have led to food security concerns around the world, particularly in urban settings. Hydroponic soilless growing methods deliver plant nutrients using water, conserving resources and can be constructed nearly anywhere. Hydroponic systems have several complex [...] Read more.

Environmental changes and the reduction in arable land have led to food security concerns around the world, particularly in urban settings. Hydroponic soilless growing methods deliver plant nutrients using water, conserving resources and can be constructed nearly anywhere. Hydroponic systems have several complex attributes that need to be managed, and this can be daunting for the layperson. Micro Indoor Smart Hydroponics (MISH) leverage Internet of Things (IoT) technology to manage the complexities of hydroponic techniques, for growing food at home for everyday citizens. Two prohibitive costs in the advancement of MISH systems are power consumption and equipment expense. Reducing cost through harvesting ambient light can potentially reduce power consumption but must be done accurately to sustain sufficient plant yields. Photosynthetic Active Radiation (PAR) meters are commercially used to measure only the light spectrum that plants use, but are expensive. This study presents Adaptalight, a MISH system that harvests ambient light using an inexpensive AS7265x IoT sensor to measure PAR. The system is built on commonly found IoT technology and a well-established architecture for MISH systems. Adpatalight was deployed in a real-world application in the living space of an apartment and experiments were carried out accordingly. A two-phase experiment was conducted over three months, each phase lasting 21 days. Phase one measured the IoT sensor’s capability to accurately measure PAR. Phase two measured the ability of the system to harvest ambient PAR light and produce sufficient yields, using the calibrated IoT sensor from phase one. The results showed that the Adaptalight system was successful in saving a significant amount of power, harvesting ambient PAR light and producing yields with no significant differences from the control. The amount of power savings would be potentially greater in a location with more ambient light. Additionally, the findings show that, when calibrated, the AS7265x sensor is well suited to accurately measure PAR light in MISH systems. Full article

(This article belongs to the Special Issue Transformation toward Sustainability in Controlled Environment Agriculture)

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16 pages, 1818 KiB

Open AccessEditor’s ChoiceArticle

Can Light Spectrum Composition Increase Growth and Nutritional Quality of Linum usitatissimum L. Sprouts and Microgreens?

by Martina Puccinelli, Rita Maggini, Luciana G. Angelini, Marco Santin, Marco Landi, Silvia Tavarini, Antonella Castagna and Luca Incrocci

Horticulturae 2022, 8(2), 98; https://doi.org/10.3390/horticulturae8020098 - 22 Jan 2022

Cited by 17 | Viewed by 5687

Abstract

Flaxseed could be suitable for obtaining high-quality sprouts and microgreens thanks to high amounts of nutrients and antioxidant, antidiabetic, and anticancer compound content in its seeds. Recent studies highlighted that seedling growth, nutritional compound, and secondary metabolite content can be strongly managed by [...] Read more.

Flaxseed could be suitable for obtaining high-quality sprouts and microgreens thanks to high amounts of nutrients and antioxidant, antidiabetic, and anticancer compound content in its seeds. Recent studies highlighted that seedling growth, nutritional compound, and secondary metabolite content can be strongly managed by regulation of the light spectrum used during germination. The present study intended to shed light on flaxseed as emerging and novel species for sprouts and microgreens and to evaluate the effect of light, with different spectrum compositions (100% blue, 100% red, 100% green, and red:green:blue—1:1:1) on the performance of flax microgreens and sprouts grown indoors under controlled conditions. Microgreens showed, compared to sprouts, a higher chlorophyll (+62.6%), carotenoid (+24.4%), and phenol content (+37.8%), antioxidant capacity (+25.1%) and a lower dry matter content (−30.7%). Besides, microgreens treated with 100% blue light were characterized by the highest content of flavonoids (2.48 mg CAE g⁻¹ FW), total phenols (3.76 mg GAE g⁻¹ FW), chlorogenic acid (1.10 mg g⁻¹ FW), and antioxidant capacity (8.06 µmol TEAC g⁻¹ FW). The paper demonstrates the feasibility of obtaining flax sprouts and microgreens indoors with a considerable antioxidant capacity and health-promoting compounds by modulating the light spectrum. Full article

(This article belongs to the Special Issue Indoor Farming and Artificial Cultivation)

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13 pages, 2736 KiB

Open AccessEditor’s ChoiceArticle

The Effect of the Double Reasoned Maturation (DMR) Method on the Chemical Composition of the Juice and Wine of the Bianca Grape Cultivar

by Diána Ágnes Nyitrainé Sárdy, Erzsébet Krisztina Németh, Réka Matolcsi, Anna Szabó and Zsuzsanna Varga

Horticulturae 2022, 8(2), 97; https://doi.org/10.3390/horticulturae8020097 - 21 Jan 2022

Cited by 1 | Viewed by 2785

Abstract

This paper aims to detect the effects of DMR (double reasoned maturation) method, and if it is able to increase the quality of Hungary’s most distributed white wine variety, Bianca. The resistant interspecific hybrid Bianca cultivar can accumulate high sugar content during ripening, [...] Read more.

This paper aims to detect the effects of DMR (double reasoned maturation) method, and if it is able to increase the quality of Hungary’s most distributed white wine variety, Bianca. The resistant interspecific hybrid Bianca cultivar can accumulate high sugar content during ripening, but it is prone to drastic acid loss, which can lead to deficient microbiological stability of wines. The DMR method is suitable for achieving fruit with better sugar/acid ratio due to the shrinking of the berries. The DMR treatment was found to be a possible tool for avoiding rapid acid loss in Bianca juices. Early cutting of one-year-old wood and early harvest were found to be the ideal combination for increasing quality. Full article

(This article belongs to the Section Viticulture)

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11 pages, 1445 KiB

Open AccessEditor’s ChoiceArticle

Hydroponic Basil Production: Temperature Influences Volatile Organic Compound Profile, but Not Overall Consumer Preference

by Kellie J. Walters and Roberto G. Lopez

Horticulturae 2022, 8(1), 76; https://doi.org/10.3390/horticulturae8010076 - 14 Jan 2022

Cited by 3 | Viewed by 2927

Abstract

Altering the growing temperature during controlled-environment production not only influences crop growth and development, but can also influence volatile organic compound (VOC) production and, subsequently, sensory attributes of culinary herbs. Therefore, the objectives of this study were to (1) quantify the influence of [...] Read more.

Altering the growing temperature during controlled-environment production not only influences crop growth and development, but can also influence volatile organic compound (VOC) production and, subsequently, sensory attributes of culinary herbs. Therefore, the objectives of this study were to (1) quantify the influence of mean daily temperature (MDT) and daily light integral (DLI) on key basil phenylpropanoid and terpenoid concentrations, (2) determine if differences in sensory characteristics due to MDT and DLI influence consumer preference, and (3) identify the sweet basil attributes consumers prefer. Thus, 2-week-old sweet basil ‘Nufar’ seedlings were transplanted into deep-flow hydroponic systems in greenhouses with target MDTs of 23, 26, 29, 32, or 35 °C and DLIs of 7, 9, or 12 mol·m⁻²·d⁻¹. After three weeks, the two most recently mature leaves were harvested for gas chromatography–mass spectrometry (GC–MS) and consumer sensory analysis. Panel evaluations were conducted through a sliding door with samples served individually while panelists answered Likert scale and open-ended quality attribute and sensory questions. The DLI did not influence VOC concentrations. Increasing MDT from 23 to 36 °C during production increased 1,8 cineole, eugenol, and methyl chavicol concentrations linearly and did not affect linalool concentration. The increases in phenylpropanoid (eugenol and methyl chavicol) were greater than increases in terpenoid (1,8 cineole) concentrations. However, these increases did not impact overall consumer or flavor preference. The MDT during basil production influenced appearance, texture, and color preference of panelists. Taken together, MDT during production influenced both VOC concentrations and textural and visual attribute preference of basil but did not influence overall consumer preference. Therefore, changing the MDT during production can be used to alter plant growth and development without significantly affecting consumer preference. Full article

(This article belongs to the Special Issue Urban Horticulture - New Trends and Technologies)

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11 pages, 3494 KiB

Open AccessEditor’s ChoiceArticle

Development of an Optical System Based on Spectral Imaging Used for a Slug Control Robot

by Christian Höing, Sharvari Raut, Abozar Nasirahmadi, Barbara Sturm and Oliver Hensel

Horticulturae 2022, 8(1), 77; https://doi.org/10.3390/horticulturae8010077 - 14 Jan 2022

Cited by 2 | Viewed by 2330

Abstract

The state-of-the-art technique to control slug pests in agriculture is the spreading of slug pellets. This method has some downsides, because slug pellets also harm beneficials and often fail because their efficiency depends on the prevailing weather conditions. This study is part of [...] Read more.

The state-of-the-art technique to control slug pests in agriculture is the spreading of slug pellets. This method has some downsides, because slug pellets also harm beneficials and often fail because their efficiency depends on the prevailing weather conditions. This study is part of a research project which is developing a pest control robot to monitor the field, detect slugs, and eliminate them. Robots represent a promising alternative to slug pellets. They work independent of weather conditions and can distinguish between pests and beneficials. As a prerequisite, a robot must be able to reliably identify slugs irrespective of the characteristics of the surrounding conditions. In this context, the utilization of computer vision and image analysis methods are challenging, because slugs look very similar to the soil, particularly in color images. Therefore, the goal of this study was to develop an optical filter-based system that distinguishes between slugs and soil. In this context, the spectral characteristics of both slugs and soil in the visible and visible near-infrared (VNIR) wavebands were measured. Conspicuous maxima followed by conspicuous local minima were found for the reflection spectra of slugs in the near infrared range from 850 nm to 990 nm]. Thus, this enabled differentiation between slugs and soils; soils showed a monotonic increase in the intensity of the relative reflection for this wavelength. The extrema determined in the reflection spectra of slugs were used to develop and set up a slug detector device consisting of a monochromatic camera, a filter changer and two narrow bandpass filters with nominal wavelengths of 925 nm and 975 nm. The developed optical system takes two photographs of the target area at night. By subtracting the pixel values of the images, the slugs are highlighted, and the soil is removed in the image due to the properties of the reflection spectra of soils and slugs. In the resulting image, the pixels of slugs were, on average, 12.4 times brighter than pixels of soil. This enabled the detection of slugs by a threshold method. Full article

(This article belongs to the Special Issue New Insights into Pest Management in Horticultural Production)

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16 pages, 3636 KiB

Open AccessEditor’s ChoiceArticle

Changes in Metal Distribution, Vegetative Growth, Reactive Oxygen and Nutrient Absorption of Tagetes patula under Soil Cadmium Stress

by Hongzhou Shi, Yangmei Wang, Hong Chen, Fuxiang Deng, Yongan Liu and Guoxing Cao

Horticulturae 2022, 8(1), 69; https://doi.org/10.3390/horticulturae8010069 - 12 Jan 2022

Cited by 6 | Viewed by 2566

Abstract

Phytoremediation with hyperaccumulator plants has been recognized as a potential way for the clearing of cadmium (Cd)-contaminated soil. In this study, hyperaccumulator Tagetes patula was treated with seven concentrations of Cd, ranging from 0 to 300 mg kg⁻¹. The Cd enrichment [...] Read more.

Phytoremediation with hyperaccumulator plants has been recognized as a potential way for the clearing of cadmium (Cd)-contaminated soil. In this study, hyperaccumulator Tagetes patula was treated with seven concentrations of Cd, ranging from 0 to 300 mg kg⁻¹. The Cd enrichment and nutrient contents in different organs during different growth phases were investigated. Under Cd concentrations ≤75 mg kg^-1, the morphological growth of T. patula did not change significantly regardless of growth stage. However, when Cd concentration exceeded 150 mg kg⁻¹, the morphological growth was remarkedly inhibited. The root/shoot ratio remained unchanged except for at 300 mg kg⁻¹. In addition, Cd negatively influenced the flowering process at the concentration of 300 mg kg⁻¹. Cd content increased significantly in Cd-treated plants. Nitrogen absorption was increased under Cd treatments, and phosphorus content was also increased under concentration ≤150 mg·kg⁻¹. However, the potassium content in the flower was decreased under 300 mg kg⁻¹. Furthermore, the contents of H₂O₂, O²⁻ and malondialdehyde were increased during the seedling phase, especially when Cd concentration was ≥150 mg kg⁻¹. In summary, T. patula showed a strong ability to tolerate Cd, and such ability might be explained by nutrient absorption and reactive oxygen clearness. Full article

(This article belongs to the Special Issue Phytotoxicity of Heavy Metals in Horticultural Plants and Security)

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13 pages, 3149 KiB

Open AccessEditor’s ChoiceArticle

Physiological, Transcriptomic Investigation on the Tea Plant Growth and Yield Motivation by Chitosan Oligosaccharides

by Lina Ou, Qiuqiu Zhang, Dezhong Ji, Yingying Li, Xia Zhou and Linhong Jin

Horticulturae 2022, 8(1), 68; https://doi.org/10.3390/horticulturae8010068 - 11 Jan 2022

Cited by 13 | Viewed by 2697

Abstract

Chitosan oligosaccharides (COS) has been abundantly studied for its application on regulating plant growth of many horticultural and agricultural crops. We presented here the effect of COS on tea plant growth and yield by physiological and transcriptomic checking. The results showed that COS [...] Read more.

Chitosan oligosaccharides (COS) has been abundantly studied for its application on regulating plant growth of many horticultural and agricultural crops. We presented here the effect of COS on tea plant growth and yield by physiological and transcriptomic checking. The results showed that COS treatment can enhance the antioxidant activity of superoxide dismutase (SOD) and peroxidase (POD) and increase the content of chlorophyll and soluble sugar in tea plants. The field trail results show that COS treatment can increase tea buds’ density by 13.81–23.16%, the weight of 100 buds by 15.94–18.15%, and the yield by 14.22–21.08%. Transcriptome analysis found 5409 COS-responsive differentially expressed genes (DEGs), including 3149 up-regulated and 2260 down-regulated genes, and concluded the possible metabolism pathway that responsible for COS promoting tea plant growth. Our results provided fundamental information for better understanding the molecular mechanisms for COS’s acting on tea plant growth and yield promotion and offer academic support for its practical application in tea plant. Full article

(This article belongs to the Special Issue Advances in Tea Plant Biology and Tea Quality Regulation)

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