Plants

22 pages, 1479 KiB

Open AccessEditor’s ChoiceArticle

Nutritional Characteristics Assessment of Sunflower Seeds, Oil and Cake. Perspective of Using Sunflower Oilcakes as a Functional Ingredient

by Ancuţa Petraru, Florin Ursachi and Sonia Amariei

Plants 2021, 10(11), 2487; https://doi.org/10.3390/plants10112487 - 17 Nov 2021

Cited by 81 | Viewed by 14844

Abstract

Ample amounts of by-products are generated from the oil industry. Among them, sunflower oilcakes have the potential to be used for human consumption, thus achieving the concept of sustainability and circular economy. The study assessed the nutritional composition of sunflower seeds, cold-pressed oil [...] Read more.

Ample amounts of by-products are generated from the oil industry. Among them, sunflower oilcakes have the potential to be used for human consumption, thus achieving the concept of sustainability and circular economy. The study assessed the nutritional composition of sunflower seeds, cold-pressed oil and the remaining press-cakes with the aim of its valorization as a food ingredient. Sunflower oil contains principally oleic (19.81%) and linoleic (64.35%) acids, which cannot be synthetized by humans and need to be assimilated through a diet. Sunflower seeds are very nutritive (33.85% proteins and 65.42% lipids and 18 mineral elements). Due to the rich content of lipids, they are principally used as a source of vegetable oil. Compared to seeds, sunflower oilcakes are richer in fibers (31.88% and 12.64% for samples in form of pellets and cake, respectively) and proteins (20.15% and 21.60%), with a balanced amino acids profile. The remaining oil (15.77% and 14.16%) is abundant in unsaturated fatty acids (95.59% and 92.12%). The comparison between the three products showed the presence of valuable components that makes them suitable for healthy diets with an adequate intake of nutrients and other bioactive compounds with benefic effects. Full article

(This article belongs to the Special Issue Quality Evaluation of Plant-Derived Foods Ⅱ)

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27 pages, 7177 KiB

Open AccessEditor’s ChoiceArticle

Physico-Chemical, Nutritional, and Sensory Evaluation of Two New Commercial Tomato Hybrids and Their Parental Lines

by Zoltán Felföldi, Floricuta Ranga, Sonia Ancuta Socaci, Anca Farcas, Mariola Plazas, Adriana F. Sestras, Dan Cristian Vodnar, Jaime Prohens and Radu E. Sestras

Plants 2021, 10(11), 2480; https://doi.org/10.3390/plants10112480 - 16 Nov 2021

Cited by 15 | Viewed by 3440

Abstract

Tomato (Solanum lycopersicum) is the globally most consumed vegetable. The objective of this research was to analyze physico-chemical, nutritional and sensorial components (taste and flavor) in two new commercial hybrids (AS 300 F1 and AS 400 F1) and their four F7 [...] Read more.

Tomato (Solanum lycopersicum) is the globally most consumed vegetable. The objective of this research was to analyze physico-chemical, nutritional and sensorial components (taste and flavor) in two new commercial hybrids (AS 300 F1 and AS 400 F1) and their four F7 parental lines. Two widely grown F1 hybrids (Precos F1 and Addalyn F1) were used as controls. The results obtained for carbohydrates (HPLC-RID) indicated that the highest values (27.82 mg/g) were recorded in the paternal line AS 10 of the new hybrid AS 400 F1. The highest values of total organic acids (HPLC-VWD) were recorded in Addalyn F1 (5.06 m/g), while the highest value of phenolic compounds (HPLC-DAD-ESI⁺) were identified in the maternal line AS 09 of the hybrid AS 400 F1 (96.3 µg/g). Intrinsic sensory values were analyzed by male and female tasters of different ages using a hedonic scale. The tasters’ perception revealed obvious taste differences between tomato genotypes. The study allowed determining genetic parameters of interest (heterosis and heterobeltosis) for the new hybrids, as well as a detailed characterization of the chemical composition and organoleptic quality of the parental breeding lines and their hybrids, which is useful in tomato breeding. Full article

(This article belongs to the Collection Advances in Plant Breeding)

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11 pages, 2944 KiB

Open AccessEditor’s ChoiceProtocol

Machine Learning-Mediated Development and Optimization of Disinfection Protocol and Scarification Method for Improved In Vitro Germination of Cannabis Seeds

by Marco Pepe, Mohsen Hesami and Andrew Maxwell Phineas Jones

Plants 2021, 10(11), 2397; https://doi.org/10.3390/plants10112397 - 6 Nov 2021

Cited by 36 | Viewed by 6399

Abstract

In vitro seed germination is a useful tool for developing a variety of biotechnologies, but cannabis has presented some challenges in uniformity and germination time, presumably due to the disinfection procedure. Disinfection and subsequent growth are influenced by many factors, such as media [...] Read more.

In vitro seed germination is a useful tool for developing a variety of biotechnologies, but cannabis has presented some challenges in uniformity and germination time, presumably due to the disinfection procedure. Disinfection and subsequent growth are influenced by many factors, such as media pH, temperature, as well as the types and levels of contaminants and disinfectants, which contribute independently and dynamically to system complexity and nonlinearity. Hence, artificial intelligence models are well suited to model and optimize this dynamic system. The current study was aimed to evaluate the effect of different types and concentrations of disinfectants (sodium hypochlorite, hydrogen peroxide) and immersion times on contamination frequency using the generalized regression neural network (GRNN), a powerful artificial neural network (ANN). The GRNN model had high prediction performance (R² > 0.91) in both training and testing. Moreover, a genetic algorithm (GA) was subjected to the GRNN to find the optimal type and level of disinfectants and immersion time to determine the best methods for contamination reduction. According to the optimization process, 4.6% sodium hypochlorite along with 0.008% hydrogen peroxide for 16.81 min would result in the best outcomes. The results of a validation experiment demonstrated that this protocol resulted in 0% contamination as predicted, but germination rates were low and sporadic. However, using this sterilization protocol in combination with the scarification of in vitro cannabis seed (seed tip removal) resulted in 0% contamination and 100% seed germination within one week. Full article

(This article belongs to the Special Issue 10th Anniversary of Plants—Recent Advances and Perspectives)

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16 pages, 2152 KiB

Open AccessEditor’s ChoiceArticle

Genotype by Trait Interaction (GT) in Maize Hybrids on Complete Fertilizer

by Seyed Mohammad Nasir Mousavi, Csaba Bojtor, Árpád Illés and János Nagy

Plants 2021, 10(11), 2388; https://doi.org/10.3390/plants10112388 - 5 Nov 2021

Cited by 18 | Viewed by 2467

Abstract

We investigated the interaction between genotype by trait, and an experiment was conducted at the University of Debrecen. Two maize cultivars, FAO340 and FAO410, were studied in a randomized complete block design with four replications. This experiment was applied to the six fertilization [...] Read more.

We investigated the interaction between genotype by trait, and an experiment was conducted at the University of Debrecen. Two maize cultivars, FAO340 and FAO410, were studied in a randomized complete block design with four replications. This experiment was applied to the six fertilization treatments. Fertilizer levels were NPK0 (control) (N:0, P2O5:0, K2O:0), NPK1 (N:30, P2O5:23, K2O:27), NPK2 (N:60, P2O5:46, K2O:54), NPK3 (N:90, P2O5:69, K2O:81), NPK4 (N:120, P2O5:92, K2O:108), and NPK5 (N:150, P2O5:115, K2O:135). The first principal component showed 54.24%, and the second principal component showed 20.75%, which explained the total squares interaction using the AMMI model in the case of the FAO410 hybrid. As regards the FAO340 hybrid, the first principal component showed 58.18%, and the second principal component showed 18.04%, explaining the total squares interaction using the AMMI model in the FAO410 hybrid. In the GGE biplot on FAO410, the first and the second principal components covered 91.20% of the total data in this analysis. Accordingly, the desirable treatment was NPK5, followed by NPK4, NPK2, NPK3, NPK1, and NPK0. NPK4 and NPK5 had the most desirable treatments for the number of seeds per row, chlorophyll, weight of 1000 seeds, and stem diameter in the case of the FAO410 hybrid. Full article

(This article belongs to the Topic Soil Fertility and Plant Nutrition for Sustainable Agriculture)

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19 pages, 1767 KiB

Open AccessEditor’s ChoiceArticle

Transient Waterlogging Events Impair Shoot and Root Physiology and Reduce Grain Yield of Durum Wheat Cultivars

by Lorenzo Cotrozzi, Giacomo Lorenzini, Cristina Nali, Claudia Pisuttu, Silvia Pampana and Elisa Pellegrini

Plants 2021, 10(11), 2357; https://doi.org/10.3390/plants10112357 - 1 Nov 2021

Cited by 29 | Viewed by 3155

Abstract

Durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn) is a staple crop of the Mediterranean countries, where more frequent waterlogging events are predicted due to climate change. However, few investigations have been conducted on the physiological and agronomic responses of this [...] Read more.

Durum wheat (Triticum turgidum L. subsp. durum (Desf.) Husn) is a staple crop of the Mediterranean countries, where more frequent waterlogging events are predicted due to climate change. However, few investigations have been conducted on the physiological and agronomic responses of this crop to waterlogging. The present study provides a comprehensive evaluation of the effects of two waterlogging durations (i.e., 14 and 35 days) on two durum wheat cultivars (i.e., Svevo and Emilio Lepido). An integrated analysis of an array of physiological, biochemical, biometric, and yield parameters was performed at the end of the waterlogging events, during recovery, and at physiological maturity. Results established that effects on durum wheat varied depending on waterlogging duration. This stress imposed at tillering impaired photosynthetic activity of leaves and determined oxidative injury of the roots. The physiological damages could not be fully recovered, subsequently slowing down tiller formation and crop growth, and depressing the final grain yield. Furthermore, differences in waterlogging tolerance between cultivars were discovered. Our results demonstrate that in durum wheat, the energy maintenance, the cytosolic ion homeostasis, and the ROS control and detoxification can be useful physiological and biochemical parameters to consider for the waterlogging tolerance of genotypes, with regard to sustaining biomass production and grain yield. Full article

(This article belongs to the Special Issue Responses of Durum Wheat to Abiotic Stress)

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20 pages, 2889 KiB

Open AccessEditor’s ChoiceArticle

Ferulic Acid and Salicylic Acid Foliar Treatments Reduce Short-Term Salt Stress in Chinese Cabbage by Increasing Phenolic Compounds Accumulation and Photosynthetic Performance

by Ida Linić, Selma Mlinarić, Lidija Brkljačić, Iva Pavlović, Ana Smolko and Branka Salopek-Sondi

Plants 2021, 10(11), 2346; https://doi.org/10.3390/plants10112346 - 29 Oct 2021

Cited by 33 | Viewed by 4307

Abstract

Salinity stress is one of the most damaging abiotic stresses to plants, causing disturbances in physiological, biochemical, and metabolic processes. The exogenous application of natural metabolites is a useful strategy to reduce the adverse effects of stress on crops. We investigated the effect [...] Read more.

Salinity stress is one of the most damaging abiotic stresses to plants, causing disturbances in physiological, biochemical, and metabolic processes. The exogenous application of natural metabolites is a useful strategy to reduce the adverse effects of stress on crops. We investigated the effect of foliar application of salicylic acid (SA) and ferulic acid (FA) (10–100 μM) on short-term salt-stressed (150 mM NaCl, 72 h) Chinese cabbage plants. Subsequently, proline level, photosynthetic performance, phenolic metabolites with special focus on selected phenolic acids (sinapic acid (SiA), FA, SA), flavonoids (quercetin (QUE), kaempferol (KAE)), and antioxidant activity were investigated in salt-stressed and phenolic acid-treated plants compared with the corresponding controls. Salt stress caused a significant increase in SA and proline contents, a decrease in phenolic compounds, antioxidant activity, and photosynthetic performance, especially due to the impairment of PSI function. SA and FA treatments, with a concentration of 10 μM, had attenuated effects on salt-stressed plants, causing a decrease in proline and SA level, and indicating that the plants suffered less metabolic disturbance. Polyphenolic compounds, especially FA, SiA, KAE, and QUE, were increased in FA and SA treatments in salt-stressed plants. Consequently, antioxidant activities were increased, and photosynthetic performances were improved. FA resulted in a better ameliorative effect on salt stress compared to SA. Full article

(This article belongs to the Special Issue Plant Polyphenols - from Plants to Human Health Volume II)

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19 pages, 2333 KiB

Open AccessEditor’s ChoiceReview

Enhancement of Phytosterol and Triterpenoid Production in Plant Hairy Root Cultures—Simultaneous Stimulation or Competition?

by Agata Rogowska and Anna Szakiel

Plants 2021, 10(10), 2028; https://doi.org/10.3390/plants10102028 - 27 Sep 2021

Cited by 22 | Viewed by 3406

Abstract

Plant in vitro cultures, including hairy roots, can be applied for controlled production of valuable natural products, such as triterpenoids and sterols. These compounds originate from the common precursor squalene. Sterols and triterpenoids distinctly differ in their functions, and the 2,3-oxidosqualene cyclization step [...] Read more.

Plant in vitro cultures, including hairy roots, can be applied for controlled production of valuable natural products, such as triterpenoids and sterols. These compounds originate from the common precursor squalene. Sterols and triterpenoids distinctly differ in their functions, and the 2,3-oxidosqualene cyclization step is often regarded as a branch point between primary and secondary (more aptly: general and specialized) metabolism. Considering the crucial role of phytosterols as membrane constituents, it has been postulated that unconstrained biosynthesis of triterpenoids can occur when sterol formation is already satisfied, and these compounds are no longer needed for cell growth and division. This hypothesis seems to follow directly the growth-defense trade-off plant dilemma. In this review, we present some examples illustrating the specific interplay between the two divergent pathways for sterol and triterpenoid biosynthesis appearing in root cultures. These studies were significant for revealing the steps of the biosynthetic pathway, understanding the role of particular enzymes, and discovering the possibility of gene regulation. Currently, hairy roots of many plant species can be considered not only as an efficient tool for production of phytochemicals, but also as suitable experimental models for investigations on regulatory mechanisms of plant metabolism. Full article

(This article belongs to the Special Issue Specialized Metabolites in Root cultures)

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13 pages, 1120 KiB

Open AccessEditor’s ChoiceReview

Integrative Pre-Breeding for Biotic Resistance in Forest Trees

by Melisa Guevara-Escudero, Angy N. Osorio and Andrés J. Cortés

Plants 2021, 10(10), 2022; https://doi.org/10.3390/plants10102022 - 26 Sep 2021

Cited by 20 | Viewed by 4540

Abstract

Climate change is unleashing novel biotic antagonistic interactions for forest trees that may jeopardize populations’ persistence. Therefore, this review article envisions highlighting major opportunities from ecological evolutionary genomics to assist the identification, conservation, and breeding of biotic resistance in forest tree species. Specifically, [...] Read more.

Climate change is unleashing novel biotic antagonistic interactions for forest trees that may jeopardize populations’ persistence. Therefore, this review article envisions highlighting major opportunities from ecological evolutionary genomics to assist the identification, conservation, and breeding of biotic resistance in forest tree species. Specifically, we first discuss how assessing the genomic architecture of biotic stress resistance enables us to recognize a more polygenic nature for a trait typically regarded Mendelian, an expectation from the Fisherian runaway pathogen–host concerted arms-race evolutionary model. Secondly, we outline innovative pipelines to capture and harness natural tree pre-adaptations to biotic stresses by merging tools from the ecology, phylo-geography, and omnigenetics fields within a predictive breeding platform. Promoting integrative ecological genomic studies promises a better understanding of antagonistic co-evolutionary interactions, as well as more efficient breeding utilization of resistant phenotypes. Full article

(This article belongs to the Special Issue Genetic Diversity, Conservation, and Innovative Plant Breeding Strategies)

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19 pages, 2278 KiB

Open AccessEditor’s ChoiceArticle

Arsenic Toxicity-Induced Physiological and Metabolic Changes in the Shoots of Pteris cretica and Spinacia oleracea

by Veronika Zemanová, Daniela Pavlíková, František Hnilička and Milan Pavlík

Plants 2021, 10(10), 2009; https://doi.org/10.3390/plants10102009 - 25 Sep 2021

Cited by 38 | Viewed by 4116

Abstract

Arsenic is a ubiquitous toxic element that can be accumulated into plant parts. The present study investigated the response of Pteris cretica and Spinacia oleracea to As treatment through the analysis of selected physiological and metabolic parameters. Plants were grown in pots in [...] Read more.

Arsenic is a ubiquitous toxic element that can be accumulated into plant parts. The present study investigated the response of Pteris cretica and Spinacia oleracea to As treatment through the analysis of selected physiological and metabolic parameters. Plants were grown in pots in As(V) spiked soil (20 and 100 mg/kg). Plants’ physiological condition was estimated through the determination of elements, gas-exchange parameters, chlorophyll fluorescence, water potential, photosynthetic pigments, and free amino acid content. The results confirmed differing As accumulation in plants, as well as in shoots and roots, which indicated that P. cretica is an As-hyperaccumulator and that S. oleracea is an As-root excluder. Variations in physiological and metabolic parameters were observed among As treatments. Overall, the results revealed a significant effect of 100 mg/kg As treatment on the analysed parameters. In both plants, this treatment affected growth, N, Mg, S, Mn, and Zn content, as well as net photosynthetic rate, chlorophyll fluorescence, and total free amino acid content. In conclusion, the results reflect the similarity between P. cretica and S. oleracea in some aspects of plants’ response to As treatment, while physiological and metabolic parameter changes related to As treatments indicate the higher sensitivity of S. oleracea. Full article

(This article belongs to the Special Issue Metal (Loid)s Tolerance in Plants)

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17 pages, 4168 KiB

Open AccessEditor’s ChoiceArticle

Thymus vulgaris Essential Oil and Its Biological Activity

by Lucia Galovičová, Petra Borotová, Veronika Valková, Nenad L. Vukovic, Milena Vukic, Jana Štefániková, Hana Ďúranová, Przemysław Łukasz Kowalczewski, Natália Čmiková and Miroslava Kačániová

Plants 2021, 10(9), 1959; https://doi.org/10.3390/plants10091959 - 19 Sep 2021

Cited by 53 | Viewed by 7485

Abstract

Thymus vulgaris essential oil has potential good biological activity. The aim of the research was to evaluate the biological activity of the T. vulgaris essential oil from the Slovak company. The main components of T. vulgaris essential oil were thymol (48.1%), p-cymene [...] Read more.

Thymus vulgaris essential oil has potential good biological activity. The aim of the research was to evaluate the biological activity of the T. vulgaris essential oil from the Slovak company. The main components of T. vulgaris essential oil were thymol (48.1%), p-cymene (11.7%), 1,8-cineole (6.7), γ-terpinene (6.1%), and carvacrol (5.5%). The antioxidant activity was 85.2 ± 0.2%, which corresponds to 479.34 ± 1.1 TEAC. The antimicrobial activity was moderate or very strong with inhibition zones from 9.89 to 22.44 mm. The lowest values of MIC were determined against B. subtilis, E. faecalis, and S. aureus. In situ antifungal analysis on bread shows that the vapor phase of T. vulgaris essential oil can inhibit the growth of the microscopic filamentous fungi of the genus Penicillium. The antimicrobial activity against S. marcescens showed 46.78–87.80% inhibition at concentrations 62.5–500 µL/mL. The MALDI TOF MS analyses suggest changes in the protein profile of biofilm forming bacteria P. fluorescens and S. enteritidis after the fifth and the ninth day, respectively. Due to the properties of the T. vulgaris essential oil, it can be used in the food industry as a natural supplement to extend the shelf life of the foods. Full article

(This article belongs to the Special Issue New Insights in the Research of Bioactive Compounds from Plant Origin with Nutraceutical and Pharmaceutical Potential)

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19 pages, 3748 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Water Deficit on Two Greek Vitis vinifera L. Cultivars: Physiology, Grape Composition and Gene Expression during Berry Development

by Anastasios Alatzas, Serafeim Theocharis, Dimitrios-Evangelos Miliordos, Konstantina Leontaridou, Angelos K. Kanellis, Yorgos Kotseridis, Polydefkis Hatzopoulos and Stefanos Koundouras

Plants 2021, 10(9), 1947; https://doi.org/10.3390/plants10091947 - 18 Sep 2021

Cited by 22 | Viewed by 3711

Abstract

Plants are exposed to numerous abiotic stresses. Drought is probably the most important of them and determines crop distribution around the world. Grapevine is considered to be a drought-resilient species, traditionally covering semiarid areas. Moreover, in the case of grapevine, moderate water deficit [...] Read more.

Plants are exposed to numerous abiotic stresses. Drought is probably the most important of them and determines crop distribution around the world. Grapevine is considered to be a drought-resilient species, traditionally covering semiarid areas. Moreover, in the case of grapevine, moderate water deficit is known to improve the quality traits of grape berries and subsequently wine composition. However, against the backdrop of climate change, vines are expected to experience sustained water deficits which could be detrimental to both grape quality and yield. The influence of water deficit on two Greek Vitis vinifera L. cultivars, ‘Agiorgitiko’ and ‘Assyrtiko’, was investigated during the 2019 and 2020 vintages. Vine physiology measurements in irrigated and non-irrigated plants were performed at three time-points throughout berry development (green berry, veraison and harvest). Berry growth and composition were examined during ripening. According to the results, water deficit resulted in reduced berry size and increased levels of soluble sugars, total phenols and anthocyanins. The expression profile of specific genes, known to control grape color, aroma and flavor was altered by water availability during maturation in a cultivar-specific manner. In agreement with the increased concentration of phenolic compounds due to water deficit, genes of the phenylpropanoid pathway in the red-skinned Agiorgitiko exhibited higher expression levels and earlier up-regulation than in the white Assyrtiko. The expression profile of the other genes during maturation or in response to water deficit was depended on the vintage. Full article

(This article belongs to the Special Issue The Effect of Abiotic Stress on Grapevine: A Physiological, Transcriptional and Metabolic Perspective)

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22 pages, 2813 KiB

Open AccessEditor’s ChoiceArticle

Ecological and Biological Properties of Satureja cuneifolia Ten. and Thymus spinulosus Ten.: Two Wild Officinal Species of Conservation Concern in Apulia (Italy). A Preliminary Survey

by Enrico V. Perrino, Francesca Valerio, Shaima Jallali, Antonio Trani and Giuseppe N. Mezzapesa

Plants 2021, 10(9), 1952; https://doi.org/10.3390/plants10091952 - 18 Sep 2021

Cited by 50 | Viewed by 3545

Abstract

This study evaluated the effects of ecology (plant community, topography and pedology), as well as of climate, on the composition of essential oils (EOs) from two officinal wild plant species (Lamiales) from Apulia, namely Satureja cuneifolia Ten. and Thymus spinulosus Ten. Few scientific [...] Read more.

This study evaluated the effects of ecology (plant community, topography and pedology), as well as of climate, on the composition of essential oils (EOs) from two officinal wild plant species (Lamiales) from Apulia, namely Satureja cuneifolia Ten. and Thymus spinulosus Ten. Few scientific data on their chemical composition are available, due to the fact that the first has a limited distribution range and the second is endemic of southern Italy. Results for both species, never officially used in traditional medicine and/or as spices, showed that the ecological context (from a phytosociological and ecological point of view) may influence their EO composition, and hence, yield chemotypes different from those reported in the literature. S. cuneifolia and Th. spinulosus can be considered good sources of phytochemicals as natural agents in organic agriculture due to the presence of thymol and α-pinene. Overall, the obtained trend for EOs suggests a potential use of both species as food, pharmacy, cosmetics and perfumery. Hence, their cultivation and use represent a positive step to reduce the use of synthetic chemicals and to meet the increasing demand for natural and healthier products. Full article

(This article belongs to the Special Issue Floristic Studies in the Light of Biodiversity Knowledge and Conservation)

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25 pages, 3064 KiB

Open AccessEditor’s ChoiceReview

Green Synthesis of Metallic Nanoparticles Using Some Selected Medicinal Plants from Southern Africa and Their Biological Applications

by Jumoke A. Aboyewa, Nicole R. S. Sibuyi, Mervin Meyer and Oluwafemi O. Oguntibeju

Plants 2021, 10(9), 1929; https://doi.org/10.3390/plants10091929 - 16 Sep 2021

Cited by 87 | Viewed by 10562

Abstract

The application of metallic nanoparticles (MNPs), especially that of silver, gold, cobalt, and zinc as antimicrobial, anticancer, drug delivery, contrast, and bioimaging agents has transformed the field of medicine. Their functions, which are attributed to their physicochemical properties, have gained prominence in various [...] Read more.

The application of metallic nanoparticles (MNPs), especially that of silver, gold, cobalt, and zinc as antimicrobial, anticancer, drug delivery, contrast, and bioimaging agents has transformed the field of medicine. Their functions, which are attributed to their physicochemical properties, have gained prominence in various technological fields. Although MNPs can be produced via rigorous physical and chemical techniques, in recent years, a biological approach utilizing natural materials has been developed. With the increasing enthusiasm for safe and efficient nanomaterials, the biological method incorporating microorganisms and plants is preferred over physical and chemical methods of nanoparticle synthesis. Of these bio-entities, plants have received great attention owing to their capability to reduce and stabilize MNPs in a single one-pot protocol. South Africa is home to ~10% of the world’s plant species, making it a major contributor to the world’s ecological scenery. Despite the documented contribution of South African plants, particularly in herbal medicine, very few of these plants have been explored for the synthesis of the noble MNPs. This paper provides a review of some important South African medicinal plants that have been utilized for the synthesis of MNPs. The enhanced biological properties of the biogenic MNPs attest to their relevance in medicine. In this endeavour, more of the African plant biodiversity must be explored for the synthesis of MNPs and be validated for their potential to be translated into future nanomedicine. Full article

(This article belongs to the Topic Frontiers in Phytochemicals)

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14 pages, 3011 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Melatonin and Carbohydrate Metabolism in Plant Cells

by Marino B. Arnao, Josefa Hernández-Ruiz, Antonio Cano and Russel J. Reiter

Plants 2021, 10(9), 1917; https://doi.org/10.3390/plants10091917 - 15 Sep 2021

Cited by 42 | Viewed by 6946

Abstract

Melatonin, a multifunctional molecule that is present in all living organisms studied, is synthesized in plant cells in several intercellular organelles including in the chloroplasts and in mitochondria. In plants, melatonin has a relevant role as a modulatory agent which improves their tolerance [...] Read more.

Melatonin, a multifunctional molecule that is present in all living organisms studied, is synthesized in plant cells in several intercellular organelles including in the chloroplasts and in mitochondria. In plants, melatonin has a relevant role as a modulatory agent which improves their tolerance response to biotic and abiotic stress. The role of melatonin in stress conditions on the primary metabolism of plant carbohydrates is reviewed in the present work. Thus, the modulatory actions of melatonin on the various biosynthetic and degradation pathways involving simple carbohydrates (mono- and disaccharides), polymers (starch), and derivatives (polyalcohols) in plants are evaluated. The possible applications of the use of melatonin in crop improvement and postharvest products are examined. Full article

(This article belongs to the Special Issue Melatonin in Plants)

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11 pages, 1199 KiB

Open AccessEditor’s ChoiceReview

The World Smallest Plants (Wolffia Sp.) as Potential Species for Bioregenerative Life Support Systems in Space

by Leone Ermes Romano and Giovanna Aronne

Plants 2021, 10(9), 1896; https://doi.org/10.3390/plants10091896 - 13 Sep 2021

Cited by 9 | Viewed by 8945

Abstract

To colonise other planets, self-sufficiency of space missions is mandatory. To date, the most promising technology to support long-duration missions is the bioregenerative life support system (BLSS), in which plants as autotrophs play a crucial role in recycling wastes and producing food and [...] Read more.

To colonise other planets, self-sufficiency of space missions is mandatory. To date, the most promising technology to support long-duration missions is the bioregenerative life support system (BLSS), in which plants as autotrophs play a crucial role in recycling wastes and producing food and oxygen. We reviewed the scientific literature on duckweed (Lemnaceae) and reported available information on plant biological traits, nutritional features, biomass production, and space applications, especially of the genus Wolffia. Results confirmed that the smallest existing higher plants are the best candidate for space BLSS. We discussed needs for further research before criticalities to be addressed to finalise the adoption of Wolffia species for space missions. Full article

(This article belongs to the Special Issue Duckweed: Research Meets Applications)

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14 pages, 1162 KiB

Open AccessEditor’s ChoiceReview

Drought Stress Memory at the Plant Cycle Level: A Review

by Cécile Jacques, Christophe Salon, Romain L. Barnard, Vanessa Vernoud and Marion Prudent

Plants 2021, 10(9), 1873; https://doi.org/10.3390/plants10091873 - 10 Sep 2021

Cited by 60 | Viewed by 7316

Abstract

Plants are sessile organisms whose survival depends on their strategy to cope with dynamic, stressful conditions. It is urgent to improve the ability of crops to adapt to recurrent stresses in order to alleviate the negative impacts on their productivity. Although our knowledge [...] Read more.

Plants are sessile organisms whose survival depends on their strategy to cope with dynamic, stressful conditions. It is urgent to improve the ability of crops to adapt to recurrent stresses in order to alleviate the negative impacts on their productivity. Although our knowledge of plant adaptation to drought has been extensively enhanced during the last decades, recent studies have tackled plant responses to recurrent stresses. The present review synthesizes the major findings from studies addressing plant responses to multiple drought events, and demonstrates the ability of plants to memorize drought stress. Stress memory is described as a priming effect allowing a different response to a reiterated stress when compared to a single stress event. Here, by specifically focusing on water stress memory at the plant cycle level, we describe the different underlying processes at the molecular, physiological and morphological levels in crops as well as in the model species Arabidopsis thaliana. Moreover, a conceptual analysis framework is proposed to study drought stress memory. Finally, the essential role of interactions between plants and soil microorganisms is emphasized during reiterated stresses because their plasticity can play a key role in supporting overall plant resilience. Full article

(This article belongs to the Special Issue Recovery and Memory of Plants during Recurrent Stresses)

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24 pages, 5527 KiB

Open AccessEditor’s ChoiceArticle

Impact of Three Different Light Spectra on the Yield, Morphology and Growth Trajectory of Three Different Cannabis sativa L. Strains

by Philipp Reichel, Sebastian Munz, Jens Hartung, Achim Präger, Stiina Kotiranta, Lisa Burgel, Torsten Schober and Simone Graeff-Hönninger

Plants 2021, 10(9), 1866; https://doi.org/10.3390/plants10091866 - 9 Sep 2021

Cited by 13 | Viewed by 5786

Abstract

Cannabis is one of the oldest cultivated plants, but plant breeding and cultivation are restricted by country specific regulations. Plant growth, morphology and metabolism can be manipulated by changing light quality and intensity. Three morphologically different strains were grown under three different light [...] Read more.

Cannabis is one of the oldest cultivated plants, but plant breeding and cultivation are restricted by country specific regulations. Plant growth, morphology and metabolism can be manipulated by changing light quality and intensity. Three morphologically different strains were grown under three different light spectra with three real light repetitions. Light dispersion was included into the statistical evaluation. The light spectra considered had an influence on the morphology of the plant, especially the height. Here, the shade avoidance induced by the lower R:FR ratio under the ceramic metal halide lamp (CHD) was of particular interest. The sugar leaves seemed to be of elementary importance in the last growth phase for yield composition. Furthermore, the last four weeks of flowering were crucial to influence the yield composition of Cannabis sativa L. through light spectra. The dry flower yield was significantly higher under both LED treatments compared to the conventional CHD light source. Our results indicate that the plant morphology can be artificially manipulated by the choice of light treatment to create shorter plants with more lateral branches which seem to be beneficial for yield development. Furthermore, the choice of cultivar has to be taken into account when interpreting results of light studies, as Cannabis sativa L. subspecies and thus bred strains highly differ in their phenotypic characteristics. Full article

(This article belongs to the Special Issue Studies on Cannabis sativa and Cannabinoids)

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13 pages, 1096 KiB

Open AccessEditor’s ChoiceArticle

Extreme Precipitation and Flooding Contribute to Sudden Vegetation Dieback in a Coastal Salt Marsh

by Camille LaFosse Stagg, Michael J. Osland, Jena A. Moon, Laura C. Feher, Claudia Laurenzano, Tiffany C. Lane, William R. Jones and Stephen B. Hartley

Plants 2021, 10(9), 1841; https://doi.org/10.3390/plants10091841 - 5 Sep 2021

Cited by 28 | Viewed by 5012

Abstract

Climate extremes are becoming more frequent with global climate change and have the potential to cause major ecological regime shifts. Along the northern Gulf of Mexico, a coastal wetland in Texas suffered sudden vegetation dieback following an extreme precipitation and flooding event associated [...] Read more.

Climate extremes are becoming more frequent with global climate change and have the potential to cause major ecological regime shifts. Along the northern Gulf of Mexico, a coastal wetland in Texas suffered sudden vegetation dieback following an extreme precipitation and flooding event associated with Hurricane Harvey in 2017. Historical salt marsh dieback events have been linked to climate extremes, such as extreme drought. However, to our knowledge, this is the first example of extreme precipitation and flooding leading to mass mortality of the salt marsh foundation species, Spartina alterniflora. Here, we investigated the relationships between baseline climate conditions, extreme climate conditions, and large-scale plant mortality to provide an indicator of ecosystem vulnerability to extreme precipitation events. We identified plant zonal boundaries along an elevation gradient with plant species tolerant of hypersaline conditions, including succulents and graminoids, at higher elevations, and flood-tolerant species, including S. alterniflora, at lower elevations. We quantified a flooding threshold for wetland collapse under baseline conditions characterized by incremental increases in flooding (i.e., sea level rise). We proposed that the sudden widespread dieback of S. alterniflora following Hurricane Harvey was the result of extreme precipitation and flooding that exceeded this threshold for S. alterniflora survival. Indeed, S. alterniflora dieback occurred at elevations above the wetland collapse threshold, illustrating a heightened vulnerability to flooding that could not be predicted from baseline climate conditions. Moreover, the spatial pattern of vegetation dieback indicated that underlying stressors may have also increased susceptibility to dieback in some S. alterniflora marshes.Collectively, our results highlight a new mechanism of sudden vegetation dieback in S. alterniflora marshes that is triggered by extreme precipitation and flooding. Furthermore, this work emphasizes the importance of considering interactions between multiple abiotic and biotic stressors that can lead to shifts in tolerance thresholds and incorporating climate extremes into climate vulnerability assessments to accurately characterize future climate threats. Full article

(This article belongs to the Special Issue Plant–Soil Interactions in Wetlands and Flooded Environments)

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12 pages, 1590 KiB

Open AccessEditor’s ChoiceArticle

Effect of Nutrient Solution Flow Rate on Hydroponic Plant Growth and Root Morphology

by Bateer Baiyin, Kotaro Tagawa, Mina Yamada, Xinyan Wang, Satoshi Yamada, Yang Shao, Ping An, Sadahiro Yamamoto and Yasuomi Ibaraki

Plants 2021, 10(9), 1840; https://doi.org/10.3390/plants10091840 - 5 Sep 2021

Cited by 23 | Viewed by 7538

Abstract

Crop production under hydroponic environments has many advantages, yet the effects of solution flow rate on plant growth remain unclear. We conducted a hydroponic cultivation study using different flow rates under light-emitting diode lighting to investigate plant growth, nutrient uptake, and root morphology [...] Read more.

Crop production under hydroponic environments has many advantages, yet the effects of solution flow rate on plant growth remain unclear. We conducted a hydroponic cultivation study using different flow rates under light-emitting diode lighting to investigate plant growth, nutrient uptake, and root morphology under different flow rates. Swiss chard plants were grown hydroponically under four nutrient solution flow rates (2 L/min, 4 L/min, 6 L/min, and 8 L/min). After 21 days, harvested plants were analyzed for root and shoot fresh weight, root and shoot dry weight, root morphology, and root cellulose and hemicellulose content. We found that suitable flow rates, acting as a eustress, gave the roots appropriate mechanical stimulation to promote root growth, absorb more nutrients, and increase overall plant growth. Conversely, excess flow rates acted as a distress that caused the roots to become compact and inhibited root surface area and root growth. Excess flow rate thereby resulted in a lower root surface area that translated to reduced nutrient ion absorption and poorer plant growth compared with plans cultured under a suitable flow rate. Our results indicate that regulating flow rate can regulate plant thigmomorphogenesis and nutrient uptake, ultimately affecting hydroponic crop quality. Full article

(This article belongs to the Special Issue Improving the Performance, Resilience and Quality of Horticultural Crops in Controlled Environments)

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18 pages, 3185 KiB

Open AccessEditor’s ChoiceArticle

Shape Matters: Plant Architecture Affects Chemical Uniformity in Large-Size Medical Cannabis Plants

by Nadav Danziger and Nirit Bernstein

Plants 2021, 10(9), 1834; https://doi.org/10.3390/plants10091834 - 3 Sep 2021

Cited by 28 | Viewed by 17698

Abstract

Since plant organs sense their environment locally, gradients of micro-climates in the plant shoot may induce spatial variability in the physiological state of the plant tissue and hence secondary metabolism. Therefore, plant architecture, which affects micro-climate in the shoot, may considerably affect the [...] Read more.

Since plant organs sense their environment locally, gradients of micro-climates in the plant shoot may induce spatial variability in the physiological state of the plant tissue and hence secondary metabolism. Therefore, plant architecture, which affects micro-climate in the shoot, may considerably affect the uniformity of cannabinoids in the Cannabis sativa plant, which has significant pharmaceutical and economic importance. Variability of micro-climates in plant shoots intensifies with the increase in plant size, largely due to an increase in inter-shoot shading. In this study, we therefore focused on the interplay between shoot architecture and the cannabinoid profile in large cannabis plants, ~2.5 m in height, with the goal to harness architecture modulation for the standardization of cannabinoid concentrations in large plants. We hypothesized that (i) a gradient of light intensity along the plants is accompanied by changes to the cannabinoid profile, and (ii) manipulations of plant architecture that increase light penetration to the plant increase cannabinoid uniformity and yield biomass. To test these hypotheses, we investigated effects of eight plant architecture manipulation treatments involving branch removals, defoliation, and pruning on plant morpho-physiology, inflorescence yield, cannabinoid profile, and uniformity. The results revealed that low cannabinoid concentrations in inflorescences at the bottom of the plants correlate with low light penetration, and that increasing light penetration by defoliation or removal of bottom branches and leaves increases cannabinoid concentrations locally and thereby through spatial uniformity, thus supporting the hypotheses. Taken together, the results reveal that shoot architectural modulation can be utilized to increase cannabinoid standardization in large cannabis plants, and that the cannabinoid profile in an inflorescence is an outcome of exogenous and endogenous factors. Full article

(This article belongs to the Special Issue Plant Biotechnology Applications in Secondary Metabolite Production)

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32 pages, 6017 KiB

Open AccessEditor’s ChoiceArticle

Arabidopsis thaliana Response to Extracellular DNA: Self Versus Nonself Exposure

by Maria Luisa Chiusano, Guido Incerti, Chiara Colantuono, Pasquale Termolino, Emanuela Palomba, Francesco Monticolo, Giovanna Benvenuto, Alessandro Foscari, Alfonso Esposito, Lucia Marti, Giulia de Lorenzo, Isaac Vega-Muñoz, Martin Heil, Fabrizio Carteni, Giuliano Bonanomi and Stefano Mazzoleni

Plants 2021, 10(8), 1744; https://doi.org/10.3390/plants10081744 - 23 Aug 2021

Cited by 32 | Viewed by 6724

Abstract

The inhibitory effect of extracellular DNA (exDNA) on the growth of conspecific individuals was demonstrated in different kingdoms. In plants, the inhibition has been observed on root growth and seed germination, demonstrating its role in plant–soil negative feedback. Several hypotheses have been proposed [...] Read more.

The inhibitory effect of extracellular DNA (exDNA) on the growth of conspecific individuals was demonstrated in different kingdoms. In plants, the inhibition has been observed on root growth and seed germination, demonstrating its role in plant–soil negative feedback. Several hypotheses have been proposed to explain the early response to exDNA and the inhibitory effect of conspecific exDNA. We here contribute with a whole-plant transcriptome profiling in the model species Arabidopsis thaliana exposed to extracellular self- (conspecific) and nonself- (heterologous) DNA. The results highlight that cells distinguish self- from nonself-DNA. Moreover, confocal microscopy analyses reveal that nonself-DNA enters root tissues and cells, while self-DNA remains outside. Specifically, exposure to self-DNA limits cell permeability, affecting chloroplast functioning and reactive oxygen species (ROS) production, eventually causing cell cycle arrest, consistently with macroscopic observations of root apex necrosis, increased root hair density and leaf chlorosis. In contrast, nonself-DNA enters the cells triggering the activation of a hypersensitive response and evolving into systemic acquired resistance. Complex and different cascades of events emerge from exposure to extracellular self- or nonself-DNA and are discussed in the context of Damage- and Pathogen-Associated Molecular Patterns (DAMP and PAMP, respectively) responses. Full article

(This article belongs to the Special Issue 10th Anniversary of Plants—Recent Advances and Perspectives)

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17 pages, 3327 KiB

Open AccessEditor’s ChoiceReview

A Review and Evaluation of the Data Supporting Internal Use of Helichrysum italicum

by Katja Kramberger, Saša Kenig, Zala Jenko Pražnikar, Nina Kočevar Glavač and Darja Barlič-Maganja

Plants 2021, 10(8), 1738; https://doi.org/10.3390/plants10081738 - 23 Aug 2021

Cited by 15 | Viewed by 5657

Abstract

Helichrysum italicum is a Mediterranean plant with various pharmacological activities. Despite extensive reports on the bioactivity of the plant, its clinically studied applications have not yet been reviewed. The aim of our study was to gather information on the internal use of H. [...] Read more.

Helichrysum italicum is a Mediterranean plant with various pharmacological activities. Despite extensive reports on the bioactivity of the plant, its clinically studied applications have not yet been reviewed. The aim of our study was to gather information on the internal use of H. italicum and its bioactive constituents to determine its efficacy and safety for human use. We reviewed research articles that have not been previously presented in this context and analyzed relevant clinical studies with H. italicum. Cochranelibrary.com revealed six eligible clinical trials with H. italicum that examined indications for pain management, cough, and mental exhaustion. Although the efficacy of H. italicum has been demonstrated both in in vitro tests and in humans, it is difficult to attribute results from clinical trials to H. italicum alone, as it has usually not been tested as the sole component. On the other hand, clinical trials provide positive information on the safety profile since no adverse effects have been reported. We conclude that H. italicum is safe to use internally, while new clinical studies with H. italicum as a single component are needed to prove its efficacy. Based on the recent trend in H. italicum research, further studies are to be expected. Full article

(This article belongs to the Special Issue Mediterranean Plants)

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18 pages, 4264 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Genomic Analysis and Secondary Metabolites Production of the Endophytic Bacillus velezensis Bvel1: A Biocontrol Agent against Botrytis cinerea Causing Bunch Rot in Post-Harvest Table Grapes

by Kallimachos Nifakos, Polina C. Tsalgatidou, Eirini-Evangelia Thomloudi, Aggeliki Skagia, Dimitrios Kotopoulis, Eirini Baira, Costas Delis, Konstantinos Papadimitriou, Emilia Markellou, Anastasia Venieraki and Panagiotis Katinakis

Plants 2021, 10(8), 1716; https://doi.org/10.3390/plants10081716 - 20 Aug 2021

Cited by 40 | Viewed by 6267

Abstract

Botrytis bunch rot caused by Botrytis cinerea is one of the most economically significant post-harvest diseases of grapes. In the present study, we showed that the bacterial strain Bvel1 is phylogenetically affiliated to Bacillus velezensis species. The strain Bvel1 and its secreted metabolites [...] Read more.

Botrytis bunch rot caused by Botrytis cinerea is one of the most economically significant post-harvest diseases of grapes. In the present study, we showed that the bacterial strain Bvel1 is phylogenetically affiliated to Bacillus velezensis species. The strain Bvel1 and its secreted metabolites exerted an antifungal activity, under in vitro conditions, against B. cinerea. UHPLC–HRMS chemical analysis revealed that iturin A2, surfactin-C13 and -C15, oxydifficidin, bacillibactin, L-dihydroanticapsin, and azelaic acid were among the metabolites secreted by Bvel1. Treatment of wounded grape berries with Bacillus sp. Bvel1 cell culture was effective for controlling grey mold ingress and expansion in vivo. The effectiveness of this biological control agent was a function of the cell culture concentration of the antagonist applied, while preventive treatment proved to be more effective compared to curative. The strain Bvel1 exhibited an adequate colonization efficiency in wounded grapes. The whole-genome phylogeny, combined with ANI and dDDH analyses, provided compelling evidence that the strain Bvel1 should be taxonomically classified as Bacillus velezensis. Genome mining approaches showed that the strain Bvel1 harbors 13 antimicrobial biosynthetic gene clusters, including iturin A, fengycin, surfactin, bacilysin, difficidin, bacillaene, and bacillibactin. The results provide new insights into the understanding of the endophytic Bacillus velezensis Bvel1 biocontrol mechanism against post-harvest fungal pathogens, including bunch rot disease in grape berries. Full article

(This article belongs to the Special Issue Control of Plant Pathogens for a Greener Future: Induced Systemic Resistance and Epigenetics)

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22 pages, 1650 KiB

Open AccessEditor’s ChoiceReview

Recent Advances in Understanding the Roles of Pectin as an Active Participant in Plant Signaling Networks

by Yesol Shin, Andrea Chane, Minjung Jung and Yuree Lee

Plants 2021, 10(8), 1712; https://doi.org/10.3390/plants10081712 - 19 Aug 2021

Cited by 52 | Viewed by 9077

Abstract

Pectin is an abundant cell wall polysaccharide with essential roles in various biological processes. The structural diversity of pectins, along with the numerous combinations of the enzymes responsible for pectin biosynthesis and modification, plays key roles in ensuring the specificity and plasticity of [...] Read more.

Pectin is an abundant cell wall polysaccharide with essential roles in various biological processes. The structural diversity of pectins, along with the numerous combinations of the enzymes responsible for pectin biosynthesis and modification, plays key roles in ensuring the specificity and plasticity of cell wall remodeling in different cell types and under different environmental conditions. This review focuses on recent progress in understanding various aspects of pectin, from its biosynthetic and modification processes to its biological roles in different cell types. In particular, we describe recent findings that cell wall modifications serve not only as final outputs of internally determined pathways, but also as key components of intercellular communication, with pectin as a major contributor to this process. The comprehensive view of the diverse roles of pectin presented here provides an important basis for understanding how cell wall-enclosed plant cells develop, differentiate, and interact. Full article

(This article belongs to the Special Issue Biotechnological Advances in Biomass and Bioenergy Production)

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14 pages, 909 KiB

Open AccessEditor’s ChoiceReview

Okra (Abelmoschus esculentus L.) as a Potential Functional Food Source of Mucilage and Bioactive Compounds with Technological Applications and Health Benefits

by Thamires Lacerda Dantas, Flávia Carolina Alonso Buriti and Eliane Rolim Florentino

Plants 2021, 10(8), 1683; https://doi.org/10.3390/plants10081683 - 16 Aug 2021

Cited by 84 | Viewed by 35588

Abstract

Abelmoschus esculentus has fruit popularly known as okra and belongs to the Malvaceae family. It is commonly used in cooking but also in traditional medicine in the treatment of worms, dysentery, inflammation, and also irritation of the stomach, intestines, and kidneys, as it [...] Read more.

Abelmoschus esculentus has fruit popularly known as okra and belongs to the Malvaceae family. It is commonly used in cooking but also in traditional medicine in the treatment of worms, dysentery, inflammation, and also irritation of the stomach, intestines, and kidneys, as it is a potential functional food. Its mucilage is a highly viscous polysaccharide that is mostly composed of monosaccharides D-galactose, L-rhamnose, and galacturonic acid, as well as proteins and minerals. The functional properties of okra mucilage have been widely studied, mainly for its potential antidiabetic activity; thus, its use as adjuvant or nutraceutical therapy for diabetes is very promising. Due to its rheological properties, it is a potential resource for pharmaceutical and food applications. Okra mucilage can be extracted by several methods, which can directly influence its physicochemical characteristics and biological activity. Features such as low cost, non-toxicity, biocompatibility, and high availability in nature arouse the interest of researchers for the study of okra mucilage. The survey of research on the applications of okra mucilage highlights the importance of using this promising source of bioactive compounds with interesting technological properties. The potential of okra as a functional food, the properties of okra mucilage, and its technological applications are discussed in this review. Full article

(This article belongs to the Topic Frontiers in Phytochemicals)

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30 pages, 6049 KiB

Open AccessEditor’s ChoiceArticle

Role of Synthetic Plant Extracts on the Production of Silver-Derived Nanoparticles

by Sabah Al-Zahrani, Sergio Astudillo-Calderón, Beatriz Pintos, Elena Pérez-Urria, José Antonio Manzanera, Luisa Martín and Arancha Gomez-Garay

Plants 2021, 10(8), 1671; https://doi.org/10.3390/plants10081671 - 13 Aug 2021

Cited by 34 | Viewed by 4863

Abstract

The main antioxidants present in plant extracts—quercetin, β-carotene, gallic acid, ascorbic acid, hydroxybenzoic acid, caffeic acid, catechin and scopoletin—are able to synthesize silver nanoparticles when reacting with a Ag NO₃ solution. The UV-visible absorption spectrum recorded with most of the antioxidants shows [...] Read more.

The main antioxidants present in plant extracts—quercetin, β-carotene, gallic acid, ascorbic acid, hydroxybenzoic acid, caffeic acid, catechin and scopoletin—are able to synthesize silver nanoparticles when reacting with a Ag NO₃ solution. The UV-visible absorption spectrum recorded with most of the antioxidants shows the characteristic surface plasmon resonance band of silver nanoparticles. Nanoparticles synthesised with ascorbic, hydroxybenzoic, caffeic, and gallic acids and scopoletin are spherical. Nanoparticles synthesised with quercetin are grouped together to form micellar structures. Nanoparticles synthesised by β-carotene, were triangular and polyhedral forms with truncated corners. Pentagonal nanoparticles were synthesized with catechin. We used Fourier-transform infrared spectroscopy to check that the biomolecules coat the synthesised silver nanoparticles. X-ray powder diffractograms showed the presence of silver, AgO, Ag₂O, Ag₃O₄ and Ag₂O₃. Rod-like structures were obtained with quercetin and gallic acid and cookie-like structures in the nanoparticles obtained with scopoletin, as a consequence of their reactivity with cyanide. This analysis explained the role played by the various agents responsible for the bio-reduction triggered by nanoparticle synthesis in their shape, size and activity. This will facilitate targeted synthesis and the application of biotechnological techniques to optimise the green synthesis of nanoparticles. Full article

(This article belongs to the Special Issue Nanotechnology Advances in Plant Science and Biotechnology)

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15 pages, 3219 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Effective Pollination Period and Parentage Effect on Pollen Tube Growth in Apple

by Stefan Roeder, Sara Serra and Stefano Musacchi

Plants 2021, 10(8), 1618; https://doi.org/10.3390/plants10081618 - 6 Aug 2021

Cited by 6 | Viewed by 6778

Abstract

Flower receptivity is a limiting factor for the fertilization of several tree fruit. The effective pollination period (EPP) can be used to determine flower longevity and identify limiting factors by assessing stigmatic receptivity, pollen tube growth rate, and ovule longevity. EPPs were determined [...] Read more.

Flower receptivity is a limiting factor for the fertilization of several tree fruit. The effective pollination period (EPP) can be used to determine flower longevity and identify limiting factors by assessing stigmatic receptivity, pollen tube growth rate, and ovule longevity. EPPs were determined for three apple cultivars under natural field conditions in Washington State in 2019 and 2020. In addition, a greenhouse study, performed under semi-controlled conditions, evaluated the influence of six maternal parents on the pollen tube growth performance of six pollen sources. The duration of the stigmatic receptivity ranged from 6.3 to 8.1 days, depending on the cultivar and year—pollen tubes required between 5.5 and 7.0 days from the stigma to reach the ovules. Ovule longevity of non-pollinated flowers varied between 8.2 and 11.3 days. Combinations of these factors resulted in EPPs ranging from 3.0 days for ‘Rubinstar’ to 5.6 days for ‘Olsentwo Gala’ in the present experimental conditions. The greenhouse study revealed that parentage affected pollen tube growth performance. Importantly, a significant interaction between maternal and paternal factors indicated that the performance of different pollen sources depended on the maternal parent and that general recommendations on pollination need to account for the maternal parent. Full article

(This article belongs to the Special Issue Floral Biology)

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20 pages, 4506 KiB

Open AccessEditor’s ChoiceArticle

Predicting Impacts of Climate Change on Northward Range Expansion of Invasive Weeds in South Korea

by Sun Hee Hong, Yong Ho Lee, Gaeun Lee, Do-Hun Lee and Pradeep Adhikari

Plants 2021, 10(8), 1604; https://doi.org/10.3390/plants10081604 - 5 Aug 2021

Cited by 27 | Viewed by 4510

Abstract

Predicting the distribution of invasive weeds under climate change is important for the early identification of areas that are susceptible to invasion and for the adoption of the best preventive measures. Here, we predicted the habitat suitability of 16 invasive weeds in response [...] Read more.

Predicting the distribution of invasive weeds under climate change is important for the early identification of areas that are susceptible to invasion and for the adoption of the best preventive measures. Here, we predicted the habitat suitability of 16 invasive weeds in response to climate change and land cover changes in South Korea using a maximum entropy modeling approach. Based on the predictions of the model, climate change is likely to increase habitat suitability. Currently, the area of moderately suitable and highly suitable habitats is estimated to be 8877.46 km², and 990.29 km², respectively, and these areas are expected to increase up to 496.52% by 2050 and 1439.65% by 2070 under the representative concentration pathways 4.5 scenario across the country. Although habitat suitability was estimated to be highest in the southern regions (<36° latitude), the central and northern regions are also predicted to have substantial increases in suitable habitat areas. Our study revealed that climate change would exacerbate the threat of northward weed invasions by shifting the climatic barriers of invasive weeds from the southern region. Thus, it is essential to initiate control and management strategies in the southern region to prevent further invasions into new areas. Full article

(This article belongs to the Special Issue Ecology of Invasive Plants)

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13 pages, 759 KiB

Open AccessEditor’s ChoiceArticle

Chemical Composition and Antimicrobial Properties of Mentha × piperita cv. ‘Kristinka’ Essential Oil

by Ippolito Camele, Daniela Gruľová and Hazem S. Elshafie

Plants 2021, 10(8), 1567; https://doi.org/10.3390/plants10081567 - 30 Jul 2021

Cited by 51 | Viewed by 5633

Abstract

Several economically important crops, fruits and vegetables are susceptible to infection by pathogenic fungi and/or bacteria postharvest or in field. Recently, plant essential oils (EOs) extracted from different medicinal and officinal plants have had promising antimicrobial effects against phytopathogens. In the present study, [...] Read more.

Several economically important crops, fruits and vegetables are susceptible to infection by pathogenic fungi and/or bacteria postharvest or in field. Recently, plant essential oils (EOs) extracted from different medicinal and officinal plants have had promising antimicrobial effects against phytopathogens. In the present study, the potential microbicide activity of Mentha × piperita cv. ‘Kristinka’ (peppermint) EO and its main constituents have been evaluated against some common phytopathogens. In addition, the cell membrane permeability of the tested fungi and the minimum fungicidal concentrations were measured. The antifungal activity was tested against the following postharvest fungi: Botrytis cinerea, Monilinia fructicola, Penicillium expansum and Aspergillus niger, whereas antibacterial activity was evaluated against Clavibacter michiganensis, Xanthomonas campestris, Pseudomonas savastanoi and P. syringae pv. phaseolicola. The chemical analysis has been carried out using GC-MS and the main components were identified as menthol (70.08%) and menthone (14.49%) followed by limonene (4.32%), menthyl acetate (3.76%) and β-caryophyllene (2.96%). The results show that the tested EO has promising antifungal activity against all tested fungi, whereas they demonstrated only a moderate antibacterial effect against some of the tested bacteria. Full article

(This article belongs to the Special Issue Plant Essential Oil with Biological Activity)

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39 pages, 495 KiB

Open AccessEditor’s ChoiceReview

A Critical Review of the Current Global Ex Situ Conservation System for Plant Agrobiodiversity. I. History of the Development of the Global System in the Context of the Political/Legal Framework and Its Major Conservation Components

by Johannes M. M. Engels and Andreas W. Ebert

Plants 2021, 10(8), 1557; https://doi.org/10.3390/plants10081557 - 29 Jul 2021

Cited by 39 | Viewed by 5864

Abstract

The history of ex situ conservation is relatively short, not more than a century old. During the middle of last century, triggered by the realization that genetic erosion was threatening the existing landraces and wild relatives of the major food crops, global efforts [...] Read more.

The history of ex situ conservation is relatively short, not more than a century old. During the middle of last century, triggered by the realization that genetic erosion was threatening the existing landraces and wild relatives of the major food crops, global efforts to collect and conserve the genetic diversity of these threatened resources were initiated, predominantly orchestrated by FAO. National and international genebanks were established to store and maintain germplasm materials, conservation methodologies were created, standards developed, and coordinating efforts were put in place to ensure effective and efficient approaches and collaboration. In the spontaneously developing global conservation system, plant breeders played an important role, aiming at the availability of genetic diversity in their breeding work. Furthermore, long-term conservation and the safety of the collected materials were the other two overriding criteria that led to the emerging international network of ex situ base collections. The political framework for the conservation of plant genetic resources finds its roots in the International Undertaking of the FAO and became ‘turbulent rapid’ with the conclusion of the Convention on Biological Diversity. This paper reviews the history of the global ex situ conservation system with a focus on the international network of base collections. It assesses the major ex situ conservation approaches and methods with their strengths and weaknesses with respect to the global conservation system and highlights the importance of combining in situ and ex situ conservation. Full article

(This article belongs to the Special Issue A Critical Review of the Current Approaches and Procedures of Plant Genetic Resources Conservation and Facilitating Use: Theory and Practice)

25 pages, 1404 KiB

Open AccessEditor’s ChoiceReview

Microbial Biostimulants as Response to Modern Agriculture Needs: Composition, Role and Application of These Innovative Products

by Adele M. Castiglione, Giuseppe Mannino, Valeria Contartese, Cinzia M. Bertea and Andrea Ertani

Plants 2021, 10(8), 1533; https://doi.org/10.3390/plants10081533 - 27 Jul 2021

Cited by 84 | Viewed by 10571

Abstract

An increasing need for a more sustainable agriculturally-productive system is required in order to preserve soil fertility and reduce soil biodiversity loss. Microbial biostimulants are innovative technologies able to ensure agricultural yield with high nutritional values, overcoming the negative effects derived from environmental [...] Read more.

An increasing need for a more sustainable agriculturally-productive system is required in order to preserve soil fertility and reduce soil biodiversity loss. Microbial biostimulants are innovative technologies able to ensure agricultural yield with high nutritional values, overcoming the negative effects derived from environmental changes. The aim of this review was to provide an overview on the research related to plant growth promoting microorganisms (PGPMs) used alone, in consortium, or in combination with organic matrices such as plant biostimulants (PBs). Moreover, the effectiveness and the role of microbial biostimulants as a biological tool to improve fruit quality and limit soil degradation is discussed. Finally, the increased use of these products requires the achievement of an accurate selection of beneficial microorganisms and consortia, and the ability to prepare for future agriculture challenges. Hence, the implementation of the microorganism positive list provided by EU (2019/1009), is desirable. Full article

(This article belongs to the Special Issue Biostimulants in Plants Science)

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17 pages, 2254 KiB

Open AccessEditor’s ChoiceArticle

Drought Tolerance Responses in Vegetable-Type Soybean Involve a Network of Biochemical Mechanisms at Flowering and Pod-Filling Stages

by Makoena Joyce Moloi and Rouxlene van der Merwe

Plants 2021, 10(8), 1502; https://doi.org/10.3390/plants10081502 - 22 Jul 2021

Cited by 23 | Viewed by 3803

Abstract

Severe drought stress affects the production of vegetable-type soybean (Glycine max L. Merrill), which is in infancy for Africa despite its huge nutritional benefits. This study was conducted under controlled environmental conditions to establish the effects of severe drought stress on ascorbate [...] Read more.

Severe drought stress affects the production of vegetable-type soybean (Glycine max L. Merrill), which is in infancy for Africa despite its huge nutritional benefits. This study was conducted under controlled environmental conditions to establish the effects of severe drought stress on ascorbate peroxidase (APX), guaiacol peroxidase (GPX), and glutathione reductase (GR) activities as well as proline, total soluble sugars (TSS), and hydrogen peroxide (H₂O₂) contents of five vegetable-type soybean cultivars (UVE8, UVE14, UVE17, AGS354, AGS429) at flowering and pod-filling stages. Drought induced significant increases in the contents of proline (selectively at pod filling for AGS429), TSS (at both stages for AGS429, and only at pod filling for UVE14), and malondialdehyde (AGS354 at flowering; UVE17 at pod filling). UVE8 and AGS354 had the highest H₂O₂ levels at flowering under drought stress, while AGS429 had the lowest. However, AGS429 was the only cultivar with significantly increased H₂O₂ under drought stress. Furthermore, drought stress induced significant increases in APX, GPX, and GR activities at flowering for AGS429. AGS354 recorded the highest decline for all antioxidative enzymes, while UVE17 decreased for GPX only. All biochemical parameters, except H₂O₂, were significantly higher at pod filling than at the flowering stage. The relationship between H₂O₂ and total seed mass (TSMP) or total seed per plant (TSP) was significantly positive for both stages, while that of TSS (at flowering) and proline (at pod filling) were significantly related to total pods per plant (TPP). The study suggests that during drought, the tolerance responses of vegetable-type soybean, APX, GPX, and GR (especially at the flowering stage), function in concert to minimize H₂O₂ production and lipid peroxidation, thereby allowing H₂O₂ to function in the signaling events leading to the induction of drought tolerance. The induction of TSS at flowering and proline at pod filling is important in the drought tolerance response of this crop. Full article

(This article belongs to the Section Plant Response to Abiotic Stress and Climate Change)

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12 pages, 2789 KiB

Open AccessEditor’s ChoiceArticle

The Application of the Essential Oils of Thymus vulgaris L. and Crithmum maritimum L. as Biocidal on Two Tholu Bommalu Indian Leather Puppets

by Giulia D’Agostino, Belinda Giambra, Franco Palla, Maurizio Bruno and Natale Badalamenti

Plants 2021, 10(8), 1508; https://doi.org/10.3390/plants10081508 - 22 Jul 2021

Cited by 39 | Viewed by 3584

Abstract

The chemical profile of the Thymus vulgaris (Lamiaceae) essential oil (EO) was investigated in order to evaluate its biological properties against microorganisms affecting two Tholu Bommalu, typical Indian leather puppets stored at the International Puppets Museum “Antonio Pasqualino” of Palermo, Italy. A [...] Read more.

The chemical profile of the Thymus vulgaris (Lamiaceae) essential oil (EO) was investigated in order to evaluate its biological properties against microorganisms affecting two Tholu Bommalu, typical Indian leather puppets stored at the International Puppets Museum “Antonio Pasqualino” of Palermo, Italy. A GC–MS analysis, using both polar and apolar columns, was used to determine the chemical composition of the essential oil. The aim of this study was to evaluate the antimicrobial effectiveness of the Thymus vulgaris and Crithmum maritimum essential oils in vapor phase to disinfect heritage leather puppets. Pieces of leather artifacts that were affected by different bacterial colonies were exposed to EO under vacuum and static evaporation conditions. The results presented showed that the vaporization of essential oil was an efficient method in the disinfection of natural skins, eradicating microorganism in short times. T. vulgaris EO in the 50% solution showed excellent inhibitory activity against isolated bacteria with both methods, but the obtained results suggest that the vacuum method allowed for faster exposition of the artifacts to the biocide. Furthermore, the biocidal properties of the essential oil of a Sicilian accession of Crithmum maritimum (Apiaceae) aerial parts were compared and investigated. The results of the latter essential oil showed a poor activity against the isolated micro-organisms. Full article

(This article belongs to the Special Issue 10th Anniversary of Plants—Recent Advances and Perspectives)

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16 pages, 996 KiB

Open AccessEditor’s ChoiceReview

Genetic and Molecular Control of Somatic Embryogenesis

by Camille Salaün, Loïc Lepiniec and Bertrand Dubreucq

Plants 2021, 10(7), 1467; https://doi.org/10.3390/plants10071467 - 17 Jul 2021

Cited by 56 | Viewed by 9620

Abstract

Somatic embryogenesis is a method of asexual reproduction that can occur naturally in various plant species and is widely used for clonal propagation, transformation and regeneration of different crops. Somatic embryogenesis shares some developmental and physiological similarities with zygotic embryogenesis as it involves [...] Read more.

Somatic embryogenesis is a method of asexual reproduction that can occur naturally in various plant species and is widely used for clonal propagation, transformation and regeneration of different crops. Somatic embryogenesis shares some developmental and physiological similarities with zygotic embryogenesis as it involves common actors of hormonal, transcriptional, developmental and epigenetic controls. Here, we provide an overview of the main signaling pathways involved in the induction and regulation of somatic embryogenesis with a focus on the master regulators of seed development, LEAFY COTYLEDON 1 and 2, ABSCISIC ACID INSENSITIVE 3 and FUSCA 3 transcription factors whose precise role during both zygotic and somatic embryogenesis remains to be fully elucidated. Full article

(This article belongs to the Special Issue New Insights into Plant Somatic Embryogenesis: Genetic and Epigenetic View)

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27 pages, 2693 KiB

Open AccessEditor’s ChoiceReview

Protein Carbonylation: Emerging Roles in Plant Redox Biology and Future Prospects

by Adesola J. Tola, Amal Jaballi and Tagnon D. Missihoun

Plants 2021, 10(7), 1451; https://doi.org/10.3390/plants10071451 - 15 Jul 2021

Cited by 28 | Viewed by 5987

Abstract

Plants are sessile in nature and they perceive and react to environmental stresses such as abiotic and biotic factors. These induce a change in the cellular homeostasis of reactive oxygen species (ROS). ROS are known to react with cellular components, including DNA, lipids, [...] Read more.

Plants are sessile in nature and they perceive and react to environmental stresses such as abiotic and biotic factors. These induce a change in the cellular homeostasis of reactive oxygen species (ROS). ROS are known to react with cellular components, including DNA, lipids, and proteins, and to interfere with hormone signaling via several post-translational modifications (PTMs). Protein carbonylation (PC) is a non-enzymatic and irreversible PTM induced by ROS. The non-enzymatic feature of the carbonylation reaction has slowed the efforts to identify functions regulated by PC in plants. Yet, in prokaryotic and animal cells, studies have shown the relevance of protein carbonylation as a signal transduction mechanism in physiological processes including hydrogen peroxide sensing, cell proliferation and survival, ferroptosis, and antioxidant response. In this review, we provide a detailed update on the most recent findings pertaining to the role of PC and its implications in various physiological processes in plants. By leveraging the progress made in bacteria and animals, we highlight the main challenges in studying the impacts of carbonylation on protein functions in vivo and the knowledge gap in plants. Inspired by the success stories in animal sciences, we then suggest a few approaches that could be undertaken to overcome these challenges in plant research. Overall, this review describes the state of protein carbonylation research in plants and proposes new research avenues on the link between protein carbonylation and plant redox biology. Full article

(This article belongs to the Special Issue Plant Cell Signalling under Stress)

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18 pages, 3036 KiB

Open AccessFeature PaperEditor’s ChoiceReview

The Optical Properties of Leaf Structural Elements and Their Contribution to Photosynthetic Performance and Photoprotection

by George Karabourniotis, Georgios Liakopoulos, Panagiota Bresta and Dimosthenis Nikolopoulos

Plants 2021, 10(7), 1455; https://doi.org/10.3390/plants10071455 - 15 Jul 2021

Cited by 56 | Viewed by 10281

Abstract

Leaves have evolved to effectively harvest light, and, in parallel, to balance photosynthetic CO₂ assimilation with water losses. At times, leaves must operate under light limiting conditions while at other instances (temporally distant or even within seconds), the same leaves must modulate [...] Read more.

Leaves have evolved to effectively harvest light, and, in parallel, to balance photosynthetic CO₂ assimilation with water losses. At times, leaves must operate under light limiting conditions while at other instances (temporally distant or even within seconds), the same leaves must modulate light capture to avoid photoinhibition and achieve a uniform internal light gradient. The light-harvesting capacity and the photosynthetic performance of a given leaf are both determined by the organization and the properties of its structural elements, with some of these having evolved as adaptations to stressful environments. In this respect, the present review focuses on the optical roles of particular leaf structural elements (the light capture module) while integrating their involvement in other important functional modules. Superficial leaf tissues (epidermis including cuticle) and structures (epidermal appendages such as trichomes) play a crucial role against light interception. The epidermis, together with the cuticle, behaves as a reflector, as a selective UV filter and, in some cases, each epidermal cell acts as a lens focusing light to the interior. Non glandular trichomes reflect a considerable part of the solar radiation and absorb mainly in the UV spectral band. Mesophyll photosynthetic tissues and biominerals are involved in the efficient propagation of light within the mesophyll. Bundle sheath extensions and sclereids transfer light to internal layers of the mesophyll, particularly important in thick and compact leaves or in leaves with a flutter habit. All of the aforementioned structural elements have been typically optimized during evolution for multiple functions, thus offering adaptive advantages in challenging environments. Hence, each particular leaf design incorporates suitable optical traits advantageously and cost-effectively with the other fundamental functions of the leaf. Full article

(This article belongs to the Special Issue Plant Tissue Optics)

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18 pages, 4184 KiB

Open AccessEditor’s ChoiceArticle

Thymus serpyllum Essential Oil and Its Biological Activity as a Modern Food Preserver

by Lucia Galovičová, Petra Borotová, Veronika Valková, Nenad L. Vukovic, Milena Vukic, Margarita Terentjeva, Jana Štefániková, Hana Ďúranová, Przemysław Łukasz Kowalczewski and Miroslava Kačániová

Plants 2021, 10(7), 1416; https://doi.org/10.3390/plants10071416 - 11 Jul 2021

Cited by 36 | Viewed by 4757

Abstract

The aim of this study was to analyze the chemical composition and biological and antibiofilm activity of the essential oil (EO) of Thymus serpyllum with the use of a MALDI-TOF MS Biotyper. The main compounds of the EO were thymol, 18.8%; carvacrol, 17.4%; [...] Read more.

The aim of this study was to analyze the chemical composition and biological and antibiofilm activity of the essential oil (EO) of Thymus serpyllum with the use of a MALDI-TOF MS Biotyper. The main compounds of the EO were thymol, 18.8%; carvacrol, 17.4%; o-cymene, 15.4%; and geraniol, 10.7%. It was found that free-radical scavenging activity was high. The highest antimicrobial activity was observed against Pseudomonas aeruginosa, Salmonella enteritidis, and biofilm-forming bacteria. The changes in the biofilm structure after T. serpyllum EO application confirmed the inhibitory action and the most pronounced effect was observed on Bacillus subtilis biofilm. The antifungal activity of the vapor phase was the most effective against Penicillium crustosum. T. serpyllum should be a suitable alternative to synthetic antioxidants as well as antimicrobials. The EO of T. serpyllum can be used in the vapor phase in the storage of root vegetables as well as a growth inhibitor of Penicillium on bread. Full article

(This article belongs to the Special Issue Chemical Composition and Antimicrobial Activity of Essential Oils)

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17 pages, 1650 KiB

Open AccessEditor’s ChoiceArticle

Chitosan-Induced Activation of the Antioxidant Defense System Counteracts the Adverse Effects of Salinity in Durum Wheat

by Filippo Quitadamo, Vanessa De Simone, Romina Beleggia and Daniela Trono

Plants 2021, 10(7), 1365; https://doi.org/10.3390/plants10071365 - 3 Jul 2021

Cited by 28 | Viewed by 2821

Abstract

The present study was carried out with the aim of (i) evaluating the effect of chitosan (CTS) on the growth of durum wheat under salinity and (ii) examining CTS-regulated mechanisms of salinity tolerance associated with the antioxidant defense system. [...] Read more.

The present study was carried out with the aim of (i) evaluating the effect of chitosan (CTS) on the growth of durum wheat under salinity and (ii) examining CTS-regulated mechanisms of salinity tolerance associated with the antioxidant defense system. To achieve these goals, durum wheat seedlings were treated with CTS at different molecular weight, low (L-CTS, 50–190 kDa), medium (M-CTS, 190–310 kDa) and high (H-CTS, 310–375 kDa). The results obtained show that exposure to 200 mM NaCl reduced the shoot and the root dried biomass by 38% and 59%, respectively. The growth impairment induced by salinity was strongly correlated with an increase in the superoxide anion production (5-fold), hydrogen peroxide content (2-fold) and malondialdehyde (MDA) content (4-fold). Seedlings responded to the oxidative stress triggered by salinity with an increase in the total phenolic content (TPC), total flavonoid content (TFC) and total antioxidant activity (TAA) by 67%, 51% and 32%, respectively. A salt-induced increase in the activity of the antioxidant enzymes superoxide dismutase and catalase (CAT) of 89% and 86%, respectively, was also observed. Treatment of salt-stressed seedlings with exogenous CTS significantly promoted seedling growth, with the strongest effects observed for L-CTS and M-CTS, which increased the shoot biomass of stressed seedlings by 32% and 44%, respectively, whereas the root dried biomass increased by 87% and 64%, respectively. L-CTS and M-CTS treatments also decreased the superoxide anion production (57% and 59%, respectively), the hydrogen peroxide content (35% and 38%, respectively) and the MDA content (48% and 56%, respectively) and increased the TPC (23% and 14%, respectively), the TFC (19% and 10%, respectively), the TAA (up to 10% and 7%, respectively) and the CAT activity (29% and 20%, respectively). Overall, our findings indicate that CTS exerts its protective role against the oxidative damages induced by salinity by enhancing the antioxidant defense system. L-CTS and M-CTS were the most effective in alleviating the adverse effect of NaCl, thus demonstrating that the CTS action is strictly related to its molecular weight. Full article

(This article belongs to the Special Issue Responses of Durum Wheat to Abiotic Stress)

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20 pages, 2399 KiB

Open AccessEditor’s ChoiceReview

Primary Root and Mesocotyl Elongation in Maize Seedlings: Two Organs with Antagonistic Growth below the Soil Surface

by Mery Nair Sáenz Rodríguez and Gladys Iliana Cassab

Plants 2021, 10(7), 1274; https://doi.org/10.3390/plants10071274 - 23 Jun 2021

Cited by 13 | Viewed by 9640

Abstract

Maize illustrates one of the most complex cases of embryogenesis in higher plants that results in the development of early embryo with distinctive organs such as the mesocotyl, seminal and primary roots, coleoptile, and plumule. After seed germination, the elongation of root and [...] Read more.

Maize illustrates one of the most complex cases of embryogenesis in higher plants that results in the development of early embryo with distinctive organs such as the mesocotyl, seminal and primary roots, coleoptile, and plumule. After seed germination, the elongation of root and mesocotyl follows opposite directions in response to specific tropisms (positive and negative gravitropism and hydrotropism). Tropisms represent the differential growth of an organ directed toward several stimuli. Although the life cycle of roots and mesocotyl takes place in darkness, their growth and functions are controlled by different mechanisms. Roots ramify through the soil following the direction of the gravity vector, spreading their tips into new territories looking for water; when water availability is low, the root hydrotropic response is triggered toward the zone with higher moisture. Nonetheless, there is a high range of hydrotropic curvatures (angles) in maize. The processes that control root hydrotropism and mesocotyl elongation remain unclear; however, they are influenced by genetic and environmental cues to guide their growth for optimizing early seedling vigor. Roots and mesocotyls are crucial for the establishment, growth, and development of the plant since both help to forage water in the soil. Mesocotyl elongation is associated with an ancient agriculture practice known as deep planting. This tradition takes advantage of residual soil humidity and continues to be used in semiarid regions of Mexico and USA. Due to the genetic diversity of maize, some lines have developed long mesocotyls capable of deep planting while others are unable to do it. Hence, the genetic and phenetic interaction of maize lines with a robust hydrotropic response and higher mesocotyl elongation in response to water scarcity in time of global heating might be used for developing more resilient maize plants. Full article

(This article belongs to the Special Issue Plant Physiology and Environmental Stresses)

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21 pages, 679 KiB

Open AccessEditor’s ChoiceReview

Importance of Landraces in Cereal Breeding for Stress Tolerance

by Daniela Marone, Maria A. Russo, Antonia Mores, Donatella B. M. Ficco, Giovanni Laidò, Anna M. Mastrangelo and Grazia M. Borrelli

Plants 2021, 10(7), 1267; https://doi.org/10.3390/plants10071267 - 22 Jun 2021

Cited by 63 | Viewed by 7705

Abstract

The renewed focus on cereal landraces is a response to some negative consequences of modern agriculture and conventional breeding which led to a reduction of genetic diversity. Cereal landraces are still cultivated on marginal lands due to their adaptability to unfavourable conditions, constituting [...] Read more.

The renewed focus on cereal landraces is a response to some negative consequences of modern agriculture and conventional breeding which led to a reduction of genetic diversity. Cereal landraces are still cultivated on marginal lands due to their adaptability to unfavourable conditions, constituting an important source of genetic diversity usable in modern plant breeding to improve the adaptation to abiotic or biotic stresses, yield performance and quality traits in limiting environments. Traditional agricultural production systems have played an important role in the evolution and conservation of wide variability in gene pools within species. Today, on-farm and ex situ conservation in gene bank collections, together with data sharing among researchers and breeders, will greatly benefit cereal improvement. Many efforts are usually made to collect, organize and phenotypically and genotypically analyse cereal landrace collections, which also utilize genomic approaches. Their use in breeding programs based on genomic selection, and the discovery of beneficial untapped QTL/genes/alleles which could be introgressed into modern varieties by MAS, pyramiding or biotechnological tools, increase the potential for their better deployment and exploitation in breeding for a more sustainable agricultural production, particularly enhancing adaptation and productivity in stress-prone environments to cope with current climate changes. Full article

(This article belongs to the Special Issue Genetic Improvement of Cereal Crops for Resistance to Biotic and Abiotic Stresses)

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12 pages, 3000 KiB

Open AccessEditor’s ChoiceArticle

Development of an Aus-Derived Nested Association Mapping (Aus-NAM) Population in Rice

by Justine K. Kitony, Hidehiko Sunohara, Mikako Tasaki, Jun-Ichi Mori, Akihisa Shimazu, Vincent P. Reyes, Hideshi Yasui, Yoshiyuki Yamagata, Atsushi Yoshimura, Masanori Yamasaki, Shunsaku Nishiuchi and Kazuyuki Doi

Plants 2021, 10(6), 1255; https://doi.org/10.3390/plants10061255 - 21 Jun 2021

Cited by 25 | Viewed by 4422

Abstract

A genetic resource for studying genetic architecture of agronomic traits and environmental adaptation is essential for crop improvements. Here, we report the development of a rice nested association mapping population (aus-NAM) using 7 aus varieties as diversity donors and T65 as [...] Read more.

A genetic resource for studying genetic architecture of agronomic traits and environmental adaptation is essential for crop improvements. Here, we report the development of a rice nested association mapping population (aus-NAM) using 7 aus varieties as diversity donors and T65 as the common parent. Aus-NAM showed broad phenotypic variations. To test whether aus-NAM was useful for quantitative trait loci (QTL) mapping, known flowering genes (Ehd1, Hd1, and Ghd7) in rice were characterized using single-family QTL mapping, joint QTL mapping, and the methods based on genome-wide association study (GWAS). Ehd1 was detected in all the seven families and all the methods. On the other hand, Hd1 and Ghd7 were detected in some families, and joint QTL mapping and GWAS-based methods resulted in weaker and uncertain peaks. Overall, the high allelic variations in aus-NAM provide a valuable genetic resource for the rice community. Full article

(This article belongs to the Special Issue Genetic Resources and Crop Improvement)

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11 pages, 1663 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Differential Detection of the Tobamoviruses Tomato Mosaic Virus (ToMV) and Tomato Brown Rugose Fruit Virus (ToBRFV) Using CRISPR-Cas12a

by Dan Mark Alon, Hagit Hak, Menachem Bornstein, Gur Pines and Ziv Spiegelman

Plants 2021, 10(6), 1256; https://doi.org/10.3390/plants10061256 - 21 Jun 2021

Cited by 38 | Viewed by 7989

Abstract

CRISPR/Cas12a-based detection is a novel approach for the efficient, sequence-specific identification of viruses. Here we adopt the use of CRISPR/Cas12a to identify the tomato brown rugose fruit virus (ToBRFV), a new and emerging tobamovirus which is causing substantial damage to the global tomato [...] Read more.

CRISPR/Cas12a-based detection is a novel approach for the efficient, sequence-specific identification of viruses. Here we adopt the use of CRISPR/Cas12a to identify the tomato brown rugose fruit virus (ToBRFV), a new and emerging tobamovirus which is causing substantial damage to the global tomato industry. Specific CRISPR RNAs (crRNAs) were designed to detect either ToBRFV or the closely related tomato mosaic virus (ToMV). This technology enabled the differential detection of ToBRFV and ToMV. Sensitivity assays revealed that viruses can be detected from 15–30 ng of RT-PCR product, and that specific detection could be achieved from a mix of ToMV and ToBRFV. In addition, we show that this method can enable the identification of ToBRFV in samples collected from commercial greenhouses. These results demonstrate a new method for species-specific detection of tobamoviruses. A future combination of this approach with isothermal amplification could provide a platform for efficient and user-friendly ways to distinguish between closely related strains and resistance-breaking pathogens. Full article

(This article belongs to the Special Issue Tobamoviruses and Interacting Viruses in Modern Agriculture)

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17 pages, 1915 KiB

Open AccessEditor’s ChoiceReview

Diverse Biosynthetic Pathways and Protective Functions against Environmental Stress of Antioxidants in Microalgae

by Shun Tamaki, Keiichi Mochida and Kengo Suzuki

Plants 2021, 10(6), 1250; https://doi.org/10.3390/plants10061250 - 19 Jun 2021

Cited by 42 | Viewed by 6564

Abstract

Eukaryotic microalgae have been classified into several biological divisions and have evolutionarily acquired diverse morphologies, metabolisms, and life cycles. They are naturally exposed to environmental stresses that cause oxidative damage due to reactive oxygen species accumulation. To cope with environmental stresses, microalgae contain [...] Read more.

Eukaryotic microalgae have been classified into several biological divisions and have evolutionarily acquired diverse morphologies, metabolisms, and life cycles. They are naturally exposed to environmental stresses that cause oxidative damage due to reactive oxygen species accumulation. To cope with environmental stresses, microalgae contain various antioxidants, including carotenoids, ascorbate (AsA), and glutathione (GSH). Carotenoids are hydrophobic pigments required for light harvesting, photoprotection, and phototaxis. AsA constitutes the AsA-GSH cycle together with GSH and is responsible for photooxidative stress defense. GSH contributes not only to ROS scavenging, but also to heavy metal detoxification and thiol-based redox regulation. The evolutionary diversity of microalgae influences the composition and biosynthetic pathways of these antioxidants. For example, α-carotene and its derivatives are specific to Chlorophyta, whereas diadinoxanthin and fucoxanthin are found in Heterokontophyta, Haptophyta, and Dinophyta. It has been suggested that AsA is biosynthesized via the plant pathway in Chlorophyta and Rhodophyta and via the Euglena pathway in Euglenophyta, Heterokontophyta, and Haptophyta. The GSH biosynthetic pathway is conserved in all biological kingdoms; however, Euglenophyta are able to synthesize an additional thiol antioxidant, trypanothione, using GSH as the substrate. In the present study, we reviewed and discussed the diversity of microalgal antioxidants, including recent findings. Full article

(This article belongs to the Special Issue Molecular and Cellular Mechanisms of the Acclimation Response in Microalgae)

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25 pages, 3652 KiB

Open AccessEditor’s ChoiceReview

Xylem Parenchyma—Role and Relevance in Wood Functioning in Trees

by Aleksandra Słupianek, Alicja Dolzblasz and Katarzyna Sokołowska

Plants 2021, 10(6), 1247; https://doi.org/10.3390/plants10061247 - 19 Jun 2021

Cited by 44 | Viewed by 14824

Abstract

Woody plants are characterised by a highly complex vascular system, wherein the secondary xylem (wood) is responsible for the axial transport of water and various substances. Previous studies have focused on the dead conductive elements in this heterogeneous tissue. However, the living xylem [...] Read more.

Woody plants are characterised by a highly complex vascular system, wherein the secondary xylem (wood) is responsible for the axial transport of water and various substances. Previous studies have focused on the dead conductive elements in this heterogeneous tissue. However, the living xylem parenchyma cells, which constitute a significant functional fraction of the wood tissue, have been strongly neglected in studies on tree biology. Although there has recently been increased research interest in xylem parenchyma cells, the mechanisms that operate in these cells are poorly understood. Therefore, the present review focuses on selected roles of xylem parenchyma and its relevance in wood functioning. In addition, to elucidate the importance of xylem parenchyma, we have compiled evidence supporting the hypothesis on the significance of parenchyma cells in tree functioning and identified the key unaddressed questions in the field. Full article

(This article belongs to the Special Issue Plant Anatomy and Biochemistry)

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56 pages, 2374 KiB

Open AccessEditor’s ChoiceReview

Innovative Delivery Systems Loaded with Plant Bioactive Ingredients: Formulation Approaches and Applications

by Anastasia Kyriakoudi, Eleni Spanidi, Ioannis Mourtzinos and Konstantinos Gardikis

Plants 2021, 10(6), 1238; https://doi.org/10.3390/plants10061238 - 18 Jun 2021

Cited by 41 | Viewed by 7249

Abstract

Plants constitute a rich source of diverse classes of valuable phytochemicals (e.g., phenolic acids, flavonoids, carotenoids, alkaloids) with proven biological activity (e.g., antioxidant, anti-inflammatory, antimicrobial, etc.). However, factors such as low stability, poor solubility and bioavailability limit their food, cosmetics and pharmaceutical applications. [...] Read more.

Plants constitute a rich source of diverse classes of valuable phytochemicals (e.g., phenolic acids, flavonoids, carotenoids, alkaloids) with proven biological activity (e.g., antioxidant, anti-inflammatory, antimicrobial, etc.). However, factors such as low stability, poor solubility and bioavailability limit their food, cosmetics and pharmaceutical applications. In this regard, a wide range of delivery systems have been developed to increase the stability of plant-derived bioactive compounds upon processing, storage or under gastrointestinal digestion conditions, to enhance their solubility, to mask undesirable flavors as well as to efficiently deliver them to the target tissues where they can exert their biological activity and promote human health. In the present review, the latest advances regarding the design of innovative delivery systems for pure plant bioactive compounds, extracts or essential oils, in order to overcome the above-mentioned challenges, are presented. Moreover, a broad spectrum of applications along with future trends are critically discussed. Full article

(This article belongs to the Special Issue Nanotechnological or Innovative Formulation Approaches for Efficient Delivery of Plant Ingredients)

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19 pages, 1295 KiB

Open AccessEditor’s ChoiceReview

Biotechnological Resources to Increase Disease-Resistance by Improving Plant Immunity: A Sustainable Approach to Save Cereal Crop Production

by Valentina Bigini, Francesco Camerlengo, Ermelinda Botticella, Francesco Sestili and Daniel V. Savatin

Plants 2021, 10(6), 1146; https://doi.org/10.3390/plants10061146 - 4 Jun 2021

Cited by 19 | Viewed by 9153

Abstract

Plant diseases are globally causing substantial losses in staple crop production, undermining the urgent goal of a 60% increase needed to meet the food demand, a task made more challenging by the climate changes. Main consequences concern the reduction of food amount and [...] Read more.

Plant diseases are globally causing substantial losses in staple crop production, undermining the urgent goal of a 60% increase needed to meet the food demand, a task made more challenging by the climate changes. Main consequences concern the reduction of food amount and quality. Crop diseases also compromise food safety due to the presence of pesticides and/or toxins. Nowadays, biotechnology represents our best resource both for protecting crop yield and for a science-based increased sustainability in agriculture. Over the last decades, agricultural biotechnologies have made important progress based on the diffusion of new, fast and efficient technologies, offering a broad spectrum of options for understanding plant molecular mechanisms and breeding. This knowledge is accelerating the identification of key resistance traits to be rapidly and efficiently transferred and applied in crop breeding programs. This review gathers examples of how disease resistance may be implemented in cereals by exploiting a combination of basic research derived knowledge with fast and precise genetic engineering techniques. Priming and/or boosting the immune system in crops represent a sustainable, rapid and effective way to save part of the global harvest currently lost to diseases and to prevent food contamination. Full article

(This article belongs to the Special Issue Biotechnological Resources for Improvement of Disease Resistance and Nutritional Quality in Staple Crops)

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15 pages, 12875 KiB

Open AccessEditor’s ChoiceArticle

Impact of Ecklonia maxima Seaweed Extract and Mo Foliar Treatments on Biofortification, Spinach Yield, Quality and NUE

by Salvatore La Bella, Beppe Benedetto Consentino, Youssef Rouphael, Georgia Ntatsi, Claudio De Pasquale, Giovanni Iapichino and Leo Sabatino

Plants 2021, 10(6), 1139; https://doi.org/10.3390/plants10061139 - 3 Jun 2021

Cited by 35 | Viewed by 4183

Abstract

Seaweed extract (SE) application is a contemporary and sustainable agricultural practice used to improve yield and quality of vegetable crops. Plant biofortification with trace element is recognized as a major tool to prevent mineral malnourishment in humans. Mo deficiency causes numerous dysfunctions, mostly [...] Read more.

Seaweed extract (SE) application is a contemporary and sustainable agricultural practice used to improve yield and quality of vegetable crops. Plant biofortification with trace element is recognized as a major tool to prevent mineral malnourishment in humans. Mo deficiency causes numerous dysfunctions, mostly connected to central nervous system and esophageal cancer. The current research was accomplished to appraise the combined effect of Ecklonia maxima brown seaweed extract (SE) and Mo dose (0, 0.5, 2, 4 or 8 µmol L⁻¹) on yield, biometric traits, minerals, nutritional and functional parameters, as well as nitrogen indices of spinach plants grown in a protected environment (tunnel). Head fresh weight (FW), ascorbic acid, polyphenols, N, P, K, Mg and nitrogen use efficiency (NUE) were positively associated with SE treatment. Moreover, head FW, head height (H), stem diameter (SD), ascorbic acid, polyphenols, carotenoids as well as NUE indices were enhanced by Mo-biofortification. A noticeable improvement in number of leaves (N. leaves), head dry matter (DM) and Mo concentration in leaf tissues was observed when SE application was combined with a Mo dosage of 4 or 8 µmol L⁻¹. Overall, our study highlighted that E. maxima SE treatment and Mo supply can improve both spinach production and quality via the key enzyme activity involved in the phytochemical homeostasis of SE and the plant nutritional status modification resulting in an enhanced spinach Mo tolerance. Full article

(This article belongs to the Special Issue Biostimulants as Growth Promoting and Stress Protecting Compounds)

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17 pages, 2099 KiB

Open AccessEditor’s ChoiceArticle

Bacillus subtilis MBI600 Promotes Growth of Tomato Plants and Induces Systemic Resistance Contributing to the Control of Soilborne Pathogens

by Anastasios Samaras, Efstathios Roumeliotis, Panagiota Ntasiou and George Karaoglanidis

Plants 2021, 10(6), 1113; https://doi.org/10.3390/plants10061113 - 31 May 2021

Cited by 67 | Viewed by 6025

Abstract

Bacillus subtilis MBI600 (Bs MBI600) is a recently commercialized plant-growth-promoting rhizobacterium (PGPR). In this study, we investigated the effects of Bs MBI600 on the growth of tomato and its biocontrol efficacy against three main soilborne tomato pathogens (Rhizoctonia solani, Pythium [...] Read more.

Bacillus subtilis MBI600 (Bs MBI600) is a recently commercialized plant-growth-promoting rhizobacterium (PGPR). In this study, we investigated the effects of Bs MBI600 on the growth of tomato and its biocontrol efficacy against three main soilborne tomato pathogens (Rhizoctonia solani, Pythium ultimum, and Fusarium oxysporum f.sp. radicis-lycopersici-Forl). Furthermore, the root colonization ability of the Bs MBI600 strain on tomato roots was analyzed in vivo with a yellow fluorescence protein (yfp)-labeled strain, revealing strong colonization ability, which was affected by the root growth substrate. The application of Bs MBI600 on tomato plants resulted in significant increases in shoot and root lengths. Transcriptional activation of two auxin-related genes (SiPin6 and SiLax4) was observed. Single applications of Bs MBI600 on inoculated tomato plants with pathogens revealed satisfactory control efficacy compared to chemical treatment. Transcriptomic analysis of defense-related genes used as markers of the salicylic acid (SA) signaling pathway (PR-1A and GLUA) or jasmonic acid/ethylene (JA/ET) signaling pathway (CHI3, LOXD, and PAL) showed increased transcription patterns in tomato plants treated with Bs MBI600 or Forl. These results indicate the biochemical and molecular mechanisms that are activated after the application of Bs MBI600 on tomato plants and suggest that induction of systemic resistance (ISR) occurred. Full article

(This article belongs to the Special Issue Control of Plant Pathogens for a Greener Future: Induced Systemic Resistance and Epigenetics)

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21 pages, 1428 KiB

Open AccessEditor’s ChoiceArticle

Potential Toxicity of Medicinal Plants Inventoried in Northeastern Morocco: An Ethnobotanical Approach

by Loubna Kharchoufa, Mohamed Bouhrim, Noureddine Bencheikh, Mohamed Addi, Christophe Hano, Hamza Mechchate and Mostafa Elachouri

Plants 2021, 10(6), 1108; https://doi.org/10.3390/plants10061108 - 31 May 2021

Cited by 25 | Viewed by 4617

Abstract

Herbal medicine and its therapeutic applications are widely practiced in northeastern Morocco, and people are knowledgeable about it. Nonetheless, there is a significant knowledge gap regarding their safety. In this study, we reveal the toxic and potential toxic species used as medicines by [...] Read more.

Herbal medicine and its therapeutic applications are widely practiced in northeastern Morocco, and people are knowledgeable about it. Nonetheless, there is a significant knowledge gap regarding their safety. In this study, we reveal the toxic and potential toxic species used as medicines by people in northeastern Morocco in order to compile and document indigenous knowledge of those herbs. Structured and semi-structured interviews were used to collect data, and simple random sampling was used as a sampling technique. Based on this information, species were collected, identified, and herbarium sheets were created. The collected data were analyzed using two quantitative indices: informant consensus factor (ICF) and fidelity level (Fl), as the degree of these indices give an insight into the level of toxicity of a given plant. The results revealed the knowledge of 55 species belonging to 36 families. The most represented families were Apiaceae, Asteraceae, Solanaceae, and Fabaceae. Furthermore, the majority of the species cited were herbs (67%), and the most common toxic parts were seeds, followed by leaves and roots. According to the informant consensus factor, death (0.81%) had the highest agreement, followed by the urological (0.76%) and skin (0.75%) categories. The most significant plants in terms of fidelity level were Solanum sodomaeum L. and Nerium oleander L. for death, Arisarum vulgare O. Targ. Tozz., Mentha spicata L., and Morus alba L. for the digestive category, Petroselinum crispum (Mill.) Fuss. and Citrus x aurantium L. for cardiovascular category, Urtica dioica L. for skin category, Datura stramonium L, and Ephedra altissima Desf. for neurological category, and finally Crocus sativus L. for general and unspecified category. This work highlights a valuable traditional knowledge of poisonous and potential poisonous plants in northeastern Morocco. Further phytochemical and toxicological research is needed to determine the safety of these prized herbs. Full article

(This article belongs to the Collection Medicinal Plants: New Advances in Phytochemicals and Their Health Benefits)

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16 pages, 1340 KiB

Open AccessEditor’s ChoiceArticle

Yield, Physiological Performance, and Phytochemistry of Basil (Ocimum basilicum L.) under Temperature Stress and Elevated CO₂ Concentrations

by T. Casey Barickman, Omolayo J. Olorunwa, Akanksha Sehgal, C. Hunt Walne, K. Raja Reddy and Wei Gao

Plants 2021, 10(6), 1072; https://doi.org/10.3390/plants10061072 - 27 May 2021

Cited by 18 | Viewed by 5993

Abstract

Early season sowing is one of the methods for avoiding yield loss for basil due to high temperatures. However, basil could be exposed to sub-optimal temperatures by planting it earlier in the season. Thus, an experiment was conducted that examines how temperature changes [...] Read more.

Early season sowing is one of the methods for avoiding yield loss for basil due to high temperatures. However, basil could be exposed to sub-optimal temperatures by planting it earlier in the season. Thus, an experiment was conducted that examines how temperature changes and carbon dioxide (CO₂) levels affect basil growth, development, and phytonutrient concentrations in a controlled environment. The experiment simulated temperature stress, low (20/12 °C), and high (38/30 °C), under ambient (420 ppm) and elevated (720 ppm) CO₂ concentrations. Low-temperature stress prompted the rapid closure of stomata resulting in a 21% decline in net photosynthesis. Chlorophylls and carotenoids decreased when elevated CO₂ interacted with low-temperature stress. Basil exhibited an increase in stomatal conductance, intercellular CO₂ concentration, apparent quantum yield, maximum photosystem II efficiency, and maximum net photosynthesis rate when subjected to high-temperature stress. Under elevated CO₂, increasing the growth temperature from 30/22 °C to 38/30 °C markedly increased the antioxidants content of basil. Taken together, the evidence from this research recommends that varying the growth temperature of basil plants can significantly affect the growth and development rates compared to increasing the CO₂ concentrations, which mitigates the adverse effects of temperature stress. Full article

(This article belongs to the Special Issue Crop Adaptation to Elevated CO₂ and Temperature)

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