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Plants, Volume 6, Issue 4 (December 2017)

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Cover Story (view full-size image) It has been known that macromolecular transport occur between phloem tissues of host- and parasitic [...] Read more.
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Open AccessCommunication Chemical Constituents and Antifungal Activity of Ficus hirta Vahl. Fruits
Plants 2017, 6(4), 44; doi:10.3390/plants6040044
Received: 1 September 2017 / Revised: 25 September 2017 / Accepted: 25 September 2017 / Published: 27 September 2017
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Abstract
Phytochemical investigation of Ficus hirta Vahl. (Moraceae) fruits led to isolate two carboline alkaloids (1 and 2), five sesquiterpenoids/norsesquiterpenoids (3–7), three flavonoids (8–10), and one phenylpropane-1,2-diol (11). Their structures were elucidated by the analysis of
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Phytochemical investigation of Ficus hirta Vahl. (Moraceae) fruits led to isolate two carboline alkaloids (1 and 2), five sesquiterpenoids/norsesquiterpenoids (3–7), three flavonoids (8–10), and one phenylpropane-1,2-diol (11). Their structures were elucidated by the analysis of their 1D and 2D NMR, and HR-ESI-MS data. All of the isolates were isolated from this species for the first time, while compounds 2, 4–6, and 8–11 were firstly reported from the genus Ficus. Antifungal assay revealed that compound 8 (namely pinocembrin-7-O-β-d-glucoside), a major flavonoid compound present in the ethanol extract of F. hirta fruits, showed good antifungal activity against Penicillium italicum, the phytopathogen of citrus blue mold caused the majority rotten of citrus fruits. Full article
(This article belongs to the Special Issue Medicinal Plants and Natural Product Research)
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Open AccessFeature PaperArticle Comparative Evaluation of Polyphenol Contents and Antioxidant Activities between Ethanol Extracts of Vitex negundo and Vitex trifolia L. Leaves by Different Methods
Plants 2017, 6(4), 45; doi:10.3390/plants6040045
Received: 30 July 2017 / Revised: 22 September 2017 / Accepted: 25 September 2017 / Published: 27 September 2017
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Abstract
The in vitro antioxidant potential assay between ethanolic extracts of two species from the genus Vitex (Vitex negundo L. and Vitex trifolia L.) belonging to the Lamiaceae family were evaluated. The antioxidant properties of different extracts prepared from both plant species were
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The in vitro antioxidant potential assay between ethanolic extracts of two species from the genus Vitex (Vitex negundo L. and Vitex trifolia L.) belonging to the Lamiaceae family were evaluated. The antioxidant properties of different extracts prepared from both plant species were evaluated by different methods. DPPH scavenging, nitric oxide scavenging, and β-carotene-linoleic acid and ferrous ion chelation methods were applied. The antioxidant activities of these two species were compared to standard antioxidants such as butylated hydroxytoluene (BHT), ascorbic acid, and Ethylene diamine tetra acetic acid (EDTA). Both species of Vitex showed significant antioxidant activity in all of the tested methods. As compared to V. trifolia L. (60.87–89.99%; 40.0–226.7 μg/mL), V. negundo has been found to hold higher antioxidant activity (62.6–94.22%; IC50 = 23.5–208.3 μg/mL) in all assays. In accordance with antioxidant activity, total polyphenol contents in V. negundo possessed greater phenolic (89.71 mg GAE/g dry weight of extract) and flavonoid content (63.11 mg QE/g dry weight of extract) as compared to that of V. trifolia (77.20 mg GAE/g and 57.41 mg QE/g dry weight of extract respectively). Our study revealed the significant correlation between the antioxidant activity and total phenolic and flavonoid contents of both plant species. Full article
(This article belongs to the Special Issue Medicinal Plants and Natural Product Research)
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Open AccessArticle Image-Based Analysis to Dissect Vertical Distribution and Horizontal Asymmetry of Conspecific Root System Interactions in Response to Planting Densities, Nutrients and Root Exudates in Arabidopsis thaliana
Plants 2017, 6(4), 46; doi:10.3390/plants6040046
Received: 24 August 2017 / Revised: 17 September 2017 / Accepted: 5 October 2017 / Published: 11 October 2017
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Abstract
Intraspecific competition is an important plant interaction that has been studied extensively aboveground, but less so belowground, due to the difficulties in accessing the root system experimentally. Recent in vivo and in situ automatic imaging advances help understand root system architecture. In this
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Intraspecific competition is an important plant interaction that has been studied extensively aboveground, but less so belowground, due to the difficulties in accessing the root system experimentally. Recent in vivo and in situ automatic imaging advances help understand root system architecture. In this study, a portable imaging platform and a scalable transplant technique were applied to test intraspecific competition in Arabidopsis thaliana. A single green fluorescent protein labeled plant was placed in the center of a grid of different planting densities of neighboring unlabeled plants or empty spaces, into which different treatments were made to the media. The root system of the central plant showed changes in the vertical distribution with increasing neighbor density, becoming more positively kurtotic, and developing an increasing negative skew with time. Horizontal root distribution was initially asymmetric, but became more evenly circular with time, and mean direction was not affected by the presence of adjacent empty spaces as initially hypothesized. To date, this is the first study to analyze the patterns of both vertical and horizontal growth in conspecific root systems. We present a portable imaging platform with simplicity, accessibility, and scalability, to capture the dynamic interactions of plant root systems. Full article
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Open AccessArticle Effect of Silicate Slag Application on Wheat Grown Under Two Nitrogen Rates
Plants 2017, 6(4), 47; doi:10.3390/plants6040047
Received: 1 September 2017 / Revised: 23 September 2017 / Accepted: 9 October 2017 / Published: 11 October 2017
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Abstract
Field studies were established on the alluvial floodplain soils in Louisiana, from 2013 to 2015, to evaluate the effect of silicate slag applications on productivity of wheat (Triticum aestivum), under sufficient and high nitrogen (N) application rates. Treatments were arranged in
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Field studies were established on the alluvial floodplain soils in Louisiana, from 2013 to 2015, to evaluate the effect of silicate slag applications on productivity of wheat (Triticum aestivum), under sufficient and high nitrogen (N) application rates. Treatments were arranged in a randomized complete block design, with four replications consisting of twelve treatments: a factorial combination of two N (101 and 145 kg N ha−1) and five silicate slag rates (0, 1, 2, 4.5, and 9 Mg ha−1), and two control plots (with and without lime). Nitrogen had a greater impact on wheat productivity than silicate slag application. Wheat grain yield reached over 7000 kg ha−1 with applications of 145 kg N, and 9 Mg silicate slag per ha for soil having Si level <20 mg kg−1. Yield increases due to N or Si were attributed to the increase in number of spike m−2 and grain number spike−1. Silicate slag application effectively raised soil pH, and availability of several plant-essential nutrients, including plant-available N (nitrate, NO3), demonstrating the benefits of slag application are beyond increasing plant-available Si. The benefits of silicate slag application were clearly observed in wheat supplied with high N, and on soil with low plant-available Si. Full article
(This article belongs to the Special Issue Practical Use of Si to Influence Plant Production)
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Open AccessArticle An Investigation of the Antioxidant Capacity in Extracts from Moringa oleifera Plants Grown in Jamaica
Plants 2017, 6(4), 48; doi:10.3390/plants6040048
Received: 18 September 2017 / Revised: 27 September 2017 / Accepted: 28 September 2017 / Published: 23 October 2017
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Abstract
Moringa oleifera trees grow well in Jamaica and their parts are popularly used locally for various purposes and ailments. Antioxidant activities in Moringa oleifera samples from different parts of the world have different ranges. This study was initiated to determine the antioxidant activity
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Moringa oleifera trees grow well in Jamaica and their parts are popularly used locally for various purposes and ailments. Antioxidant activities in Moringa oleifera samples from different parts of the world have different ranges. This study was initiated to determine the antioxidant activity of Moringa oleifera grown in Jamaica. Dried and milled Moringa oleifera leaves were extracted with ethanol/water (4:1) followed by a series of liquid–liquid extractions. The antioxidant capacities of all fractions were tested using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. IC50 values (the amount of antioxidant needed to reduce 50% of DPPH) were then determined and values for the extracts ranged from 177 to 4458 μg/mL. Extracts prepared using polar solvents had significantly higher antioxidant capacities than others and may have clinical applications in any disease characterized by a chronic state of oxidative stress, such as sickle cell anemia. Further work will involve the assessment of these extracts in a sickle cell model of oxidative stress. Full article
(This article belongs to the Special Issue Medicinal Plants and Natural Product Research)
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Open AccessFeature PaperArticle Diffusive and Metabolic Constraints to Photosynthesis in Quinoa during Drought and Salt Stress
Plants 2017, 6(4), 49; doi:10.3390/plants6040049
Received: 25 September 2017 / Revised: 11 October 2017 / Accepted: 13 October 2017 / Published: 17 October 2017
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Abstract
Quinoa (Chenopodium quinoa Willd.) has been proposed as a hardy alternative to traditional grain crops in areas with warm-to-hot climates that are likely to experience increased drought and salt stress in the future. We characterised the diffusive and metabolic limitations to photosynthesis
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Quinoa (Chenopodium quinoa Willd.) has been proposed as a hardy alternative to traditional grain crops in areas with warm-to-hot climates that are likely to experience increased drought and salt stress in the future. We characterised the diffusive and metabolic limitations to photosynthesis in quinoa exposed to drought and salt stress in isolation and combination. Drought-induced pronounced stomatal and mesophyll limitations to CO2 transport, but quinoa retained photosynthetic capacity and photosystem II (PSII) performance. Saline water (300 mmol NaCl-equivalent to 60% of the salinity of sea-water) supplied in identical volumes to the irrigation received by the control and drought treatments induced similar reductions in stomatal and mesophyll conductance, but also reduced carboxylation of ribulose-1,5-bisphosphate carboxylase/oxygenase, regeneration of ribulose-1,5-bisphosphate, increased non-photochemical dissipation of energy as heat and impaired PSII electron transport. This suggests that ion toxicity reduced PN via interference with photosynthetic enzymes and degradation of pigment–protein complexes within the thylakoid membranes. The results of this study demonstrate that the photosynthetic physiology of quinoa is resistant to the effects of drought, but quinoa may not be a suitable crop for areas subject to strong salt stress or irrigation with a concentration of saline water equivalent to a 300 mmol NaCl solution. Full article
(This article belongs to the Special Issue Plant Adaptation to Climate Change)
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Open AccessArticle Proanthocyanidin Characterization, Antioxidant and Cytotoxic Activities of Three Plants Commonly Used in Traditional Medicine in Costa Rica: Petiveria alliaceae L., Phyllanthus niruri L. and Senna reticulata Willd.
Plants 2017, 6(4), 50; doi:10.3390/plants6040050
Received: 5 September 2017 / Revised: 10 October 2017 / Accepted: 15 October 2017 / Published: 19 October 2017
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Abstract
The phenolic composition of aerial parts from Petiveria alliaceae L., Phyllanthus niruri L. and Senna reticulata Willd., species commonly used in Costa Rica as traditional medicines, was studied using UPLC-ESI-TQ-MS on enriched-phenolic extracts. Comparatively, higher values of total phenolic content (TPC), as measured
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The phenolic composition of aerial parts from Petiveria alliaceae L., Phyllanthus niruri L. and Senna reticulata Willd., species commonly used in Costa Rica as traditional medicines, was studied using UPLC-ESI-TQ-MS on enriched-phenolic extracts. Comparatively, higher values of total phenolic content (TPC), as measured by the Folin-Ciocalteau method, were observed for P. niruri extracts (328.8 gallic acid equivalents/g) than for S. reticulata (79.30 gallic acid equivalents/g) whereas P. alliaceae extract showed the lowest value (13.45 gallic acid equivalents/g). A total of 20 phenolic acids and proanthocyanidins were identified in the extracts, including hydroxybenzoic acids (benzoic, 4-hydroxybenzoic, gallic, prochatechuic, salicylic, syringic and vanillic acids); hydroxycinnamic acids (caffeic, ferulic, and p-coumaric acids); and flavan-3-ols monomers [(+)-catechin and (−)-epicatechin)]. Regarding proanthocyanidin oligomers, five procyanidin dimers (B1, B2, B3, B4, and B5) and one trimer (T2) are reported for the first time in P. niruri, as well as two propelargonidin dimers in S. reticulata. Additionally, P. niruri showed the highest antioxidant DPPH and ORAC values (IC50 of 6.4 μg/mL and 6.5 mmol TE/g respectively), followed by S. reticulata (IC50 of 72.9 μg/mL and 2.68 mmol TE/g respectively) and P. alliaceae extract (IC50 >1000 μg/mL and 1.32 mmol TE/g respectively). Finally, cytotoxicity and selectivity on gastric AGS and colon SW20 adenocarcinoma cell lines were evaluated and the best values were also found for P. niruri (SI = 2.8), followed by S. reticulata (SI = 2.5). Therefore, these results suggest that extracts containing higher proanthocyanidin content also show higher bioactivities. Significant positive correlation was found between TPC and ORAC (R2 = 0.996) as well as between phenolic content as measured by UPLC-DAD and ORAC (R2 = 0.990). These findings show evidence for the first time of the diversity of phenolic acids in P. alliaceae and S. reticulata, and the presence of proanthocyanidins as minor components in latter species. Of particular relevance is the occurrence of proanthocyanidin oligomers in phenolic extracts from P. niruri and their potential bioactivity. Full article
(This article belongs to the Special Issue Medicinal Plants and Natural Product Research)
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Open AccessArticle Effects of Silicon Amendment on Soilborne and Fruit Diseases of Avocado
Plants 2017, 6(4), 51; doi:10.3390/plants6040051
Received: 1 September 2017 / Revised: 16 October 2017 / Accepted: 16 October 2017 / Published: 20 October 2017
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Abstract
The effects of silicon (Si) amendment have been studied in several plant/pathogen interactions; however, studies in horticultural tree crops are limited. Effects of amendment with soluble potassium silicate (AgSil®32, approximately 30% available Si), or milled cement building board by-products (Mineral Mulch
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The effects of silicon (Si) amendment have been studied in several plant/pathogen interactions; however, studies in horticultural tree crops are limited. Effects of amendment with soluble potassium silicate (AgSil®32, approximately 30% available Si), or milled cement building board by-products (Mineral Mulch (MM) or Mineral Dust (MD), containing 5% available Si) were investigated in field and greenhouse trials with avocado. Orchard soil drench applications with potassium silicate improved yield and quality of fruit, but visual health of trees declining from Phytophthora root rot (PRR) was not affected. Orchard spray or trunk injection applications with potassium silicate were ineffective. Amendment of potting mix with MM and MD reduced root necrosis of avocado seedlings after inoculation with Calonectria ilicicola, an aggressive soilborne pathogen causing black root rot. Application of MM to mature orchard trees declining with PRR had a beneficial effect on visual tree health, and Si accumulation in leaves and fruit peel, after only 10 months. Products that deliver available Si consistently for uptake are likely to be most successful in perennial tree crops. Full article
(This article belongs to the Special Issue Practical Use of Si to Influence Plant Production)
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Open AccessArticle In Situ Dark Adaptation Enhances the Efficiency of DNA Extraction from Mature Pin Oak (Quercus palustris) Leaves, Facilitating the Identification of Partial Sequences of the 18S rRNA and Isoprene Synthase (IspS) Genes
Plants 2017, 6(4), 52; doi:10.3390/plants6040052
Received: 28 August 2017 / Revised: 29 September 2017 / Accepted: 19 October 2017 / Published: 24 October 2017
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Abstract
Mature oak (Quercus spp.) leaves, although abundantly available during the plants’ developmental cycle, are rarely exploited as viable sources of genomic DNA. These leaves are rich in metabolites difficult to remove during standard DNA purification, interfering with downstream molecular genetics applications. The
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Mature oak (Quercus spp.) leaves, although abundantly available during the plants’ developmental cycle, are rarely exploited as viable sources of genomic DNA. These leaves are rich in metabolites difficult to remove during standard DNA purification, interfering with downstream molecular genetics applications. The current work assessed whether in situ dark adaptation, to deplete sugar reserves and inhibit secondary metabolite synthesis could compensate for the difficulties encountered when isolating DNA from mature leaves rich in secondary metabolites. We optimized a rapid, commercial kit based method to extract genomic DNA from dark- and light-adapted leaves. We demonstrated that in situ dark adaptation increases the yield and quality of genomic DNA obtained from mature oak leaves, yielding templates of sufficiently high quality for direct downstream applications, such as PCR amplification and gene identification. The quality of templates isolated from dark-adapted pin oak leaves particularly improved the amplification of larger fragments in our experiments. From DNA extracts prepared with our optimized method, we identified for the first time partial segments of the genes encoding 18S rRNA and isoprene synthase (IspS) from pin oak (Quercus palustris), whose full genome has not yet been sequenced. Full article
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Open AccessFeature PaperArticle Genus-Specific Real-Time PCR and HRM Assays to Distinguish Liriope from Ophiopogon Samples
Plants 2017, 6(4), 53; doi:10.3390/plants6040053
Received: 20 September 2017 / Revised: 17 October 2017 / Accepted: 19 October 2017 / Published: 26 October 2017
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Abstract
Liriope and Ophiopogon species have a long history of use as traditional medicines across East Asia. They have also become widely used around the world for ornamental and landscaping purposes. The morphological similarities between Liriope and Ophiopogon taxa have made the taxonomy of
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Liriope and Ophiopogon species have a long history of use as traditional medicines across East Asia. They have also become widely used around the world for ornamental and landscaping purposes. The morphological similarities between Liriope and Ophiopogon taxa have made the taxonomy of the two genera problematic and caused confusion about the identification of individual specimens. Molecular approaches could be a useful tool for the discrimination of these two genera in combination with traditional methods. Seventy-five Liriope and Ophiopogon samples from the UK National Plant Collections of Ophiopogon and Liriope were analyzed. The 5′ end of the DNA barcode region of the gene for the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcLa) was used for the discrimination of the two genera. A single nucleotide polymorphism (SNP) between the two genera allowed the development of discriminatory tests for genus-level identification based on specific PCR and high-resolution melt curve (HRM) assays. The study highlights the advantage of incorporating DNA barcoding methods into plant identification protocols and provides simple assays that could be used for the quality assurance of commercially traded plants and herbal drugs. Full article
(This article belongs to the Special Issue Medicinal Plants and Natural Product Research)
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Open AccessCommunication Development of pGEMINI, a Plant Gateway Destination Vector Allowing the Simultaneous Integration of Two cDNA via a Single LR-Clonase Reaction
Plants 2017, 6(4), 55; doi:10.3390/plants6040055
Received: 27 October 2017 / Revised: 6 November 2017 / Accepted: 10 November 2017 / Published: 12 November 2017
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Abstract
Gateway technology has been used to facilitate the generation of a large number of constructs for the modification of plants for research purposes. However, many of the currently available vectors only allow the integration of a single cDNA of interest into an expression
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Gateway technology has been used to facilitate the generation of a large number of constructs for the modification of plants for research purposes. However, many of the currently available vectors only allow the integration of a single cDNA of interest into an expression clone. The ability to over-express multiple genes in combination is essential for the study of plant development where several transcripts have a role to play in one or more metabolic processes. The tools to carry out such studies are limited, and in many cases rely on the incorporation of cDNA into expression systems via conventional cloning, which can be both time consuming and laborious. To our knowledge, this study reports on the first development of a vector allowing the simultaneous integration of two independent cDNAs via a single LR-clonase reaction. This vector “pGEMINI” represents a powerful molecular tool offering the ability to study the role of multi-cDNA constructs on plant development, and opens up the process of gene stacking and the study of gene combinations through transient or stable transformation procedures. Full article
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Open AccessArticle Morphological Variation and Inter-Relationships of Quantitative Traits in Enset (Ensete ventricosum (welw.) Cheesman) Germplasm from South and South-Western Ethiopia
Plants 2017, 6(4), 56; doi:10.3390/plants6040056
Received: 21 October 2017 / Revised: 7 November 2017 / Accepted: 9 November 2017 / Published: 6 December 2017
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Abstract
Enset (Ensete ventricosum (Welw.) Cheesman) is Ethiopia’s most important root crop. A total of 387 accessions collected from nine different regions of Ethiopia were evaluated for 15 quantitative traits at Areka Agricultural Research Centre to determine the extent and pattern of distribution
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Enset (Ensete ventricosum (Welw.) Cheesman) is Ethiopia’s most important root crop. A total of 387 accessions collected from nine different regions of Ethiopia were evaluated for 15 quantitative traits at Areka Agricultural Research Centre to determine the extent and pattern of distribution of morphological variation. The variations among the accessions and regions were significant (p ≤ 0.01) for all the 15 traits studied. Mean for plant height, central shoot weight before grating, and fermented squeezed kocho yield per hectare per year showed regional variation along an altitude gradient and across cultural differences related to the origin of the collection. Furthermore, there were significant correlations among most of the characters. This included the correlation among agronomic characteristics of primary interest in enset breeding such as plant height, pseudostem height, and fermented squeezed kocho yield per hectare per year. Altitude of the collection sites also significantly impacted the various characteristics studied. These results reveal the existence of significant phenotypic variations among the 387 accessions as a whole. Regional differentiations were also evident among the accessions. The implication of the current results for plant breeding, germplasm collection, and in situ and ex situ genetic resource conservation are discussed. Full article
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Open AccessFeature PaperArticle Climate Modelling Shows Increased Risk to Eucalyptus sideroxylon on the Eastern Coast of Australia Compared to Eucalyptus albens
Plants 2017, 6(4), 58; doi:10.3390/plants6040058
Received: 29 September 2017 / Revised: 21 November 2017 / Accepted: 22 November 2017 / Published: 24 November 2017
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Abstract
Aim: To identify the extent and direction of range shift of Eucalyptus sideroxylon and E. albens in Australia by 2050 through an ensemble forecast of four species distribution models (SDMs). Each was generated using four global climate models (GCMs), under two representative concentration
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Aim: To identify the extent and direction of range shift of Eucalyptus sideroxylon and E. albens in Australia by 2050 through an ensemble forecast of four species distribution models (SDMs). Each was generated using four global climate models (GCMs), under two representative concentration pathways (RCPs). Location: Australia. Methods: We used four SDMs of (i) generalized linear model, (ii) MaxEnt, (iii) random forest, and (iv) boosted regression tree to construct SDMs for species E. sideroxylon and E. albens under four GCMs including (a) MRI-CGCM3, (b) MIROC5, (c) HadGEM2-AO and (d) CCSM4, under two RCPs of 4.5 and 6.0. Here, the true skill statistic (TSS) index was used to assess the accuracy of each SDM. Results: Results showed that E. albens and E. sideroxylon will lose large areas of their current suitable range by 2050 and E. sideroxylon is projected to gain in eastern and southeastern Australia. Some areas were also projected to remain suitable for each species between now and 2050. Our modelling showed that E. sideroxylon will lose suitable habitat on the western side and will not gain any on the eastern side because this region is one the most heavily populated areas in the country, and the populated areas are moving westward. The predicted decrease in E. sideroxylon’s distribution suggests that land managers should monitor its population closely, and evaluate whether it meets criteria for a protected legal status. Main conclusions: Both Eucalyptus sideroxylon and E. albens will be negatively affected by climate change and it is projected that E. sideroxylon will be at greater risk of losing habitat than E. albens. Full article
(This article belongs to the Special Issue Plant Adaptation to Climate Change)
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Open AccessCommunication Ethnobotanical Survey, Preliminary Physico-Chemical and Phytochemical Screening of Salvia argentea (L.) Used by Herbalists of the Saïda Province in Algeria
Plants 2017, 6(4), 59; doi:10.3390/plants6040059
Received: 7 November 2017 / Revised: 29 November 2017 / Accepted: 1 December 2017 / Published: 5 December 2017
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Abstract
An ethnobotanical study was carried out in the Saïda region among herbalists to evaluate the use of Salvia argentea (L.), a plant species native from North Africa belonging to the Lamiaceae family. Forty-two herbalists were interviewed individually, aged between 30 and 70 years,
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An ethnobotanical study was carried out in the Saïda region among herbalists to evaluate the use of Salvia argentea (L.), a plant species native from North Africa belonging to the Lamiaceae family. Forty-two herbalists were interviewed individually, aged between 30 and 70 years, all males, 52.38% of them having received a secondary education level and having performing their duties for more than a decade. This study showed that Salvia argentea is used specifically in the treatment of diseases of the respiratory system. The leaves are the most commonly used part, usually in the form of powder and exclusively administered orally. The preliminary results of the physicochemical characterization and the phytochemical screening of the powdered leaves of Salvia argentea attest to their safety and confer them a guarantee of phytotherapeutic quality. Full article
(This article belongs to the Special Issue Lamiaceae Species: Biology, Ecology and Practical Uses)
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Open AccessFeature PaperArticle Phloem-Conducting Cells in Haustoria of the Root-Parasitic Plant Phelipanche aegyptiaca Retain Nuclei and Are Not Mature Sieve Elements
Plants 2017, 6(4), 60; doi:10.3390/plants6040060
Received: 3 November 2017 / Revised: 29 November 2017 / Accepted: 3 December 2017 / Published: 5 December 2017
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Abstract
Phelipanche aegyptiaca parasitizes a wide range of plants, including important crops, and causes serious damage to their production. P. aegyptiaca develops a specialized intrusive organ called a haustorium that establishes connections to the host’s xylem and phloem. In parallel with the development of
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Phelipanche aegyptiaca parasitizes a wide range of plants, including important crops, and causes serious damage to their production. P. aegyptiaca develops a specialized intrusive organ called a haustorium that establishes connections to the host’s xylem and phloem. In parallel with the development of xylem vessels, the differentiation of phloem-conducting cells has been demonstrated by the translocation of symplasmic tracers from the host to the parasite. However, it is unclear yet whether haustorial phloem-conducting cells are sieve elements. In this study, we identified phloem-conducting cells in haustoria by the host-to-parasite translocation of green fluorescent protein (GFP) from AtSUC2pro::GFP tomato sieve tubes. Haustorial GFP-conducting cells contained nuclei but not callose-rich sieve plates, indicating that phloem-conducting cells in haustoria differ from conventional sieve elements. To ascertain why the nuclei were not degenerated, expression of the P. aegyptiaca homologs NAC-domain containing transcription factor (NAC45), NAC45/86-dependent exonuclease-domain protein 1 (NEN1), and NEN4 was examined. However, these genes were more highly expressed in the haustorium than in tubercle protrusion, implying that nuclear degradation in haustoria may not be exclusively controlled by the NAC45/86-NEN regulatory pathway. Our results also suggest that the formation of plasmodesmata with large size exclusion limits is independent of nuclear degradation and callose deposition. Full article
(This article belongs to the Special Issue Plasmodesmata and Intercellular Movement)
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Open AccessFeature PaperArticle Comparative Analysis of the Nitrogen Effect of Common Agricultural Practices and Rotation Systems in a Rainfed Mediterranean Environment
Plants 2017, 6(4), 61; doi:10.3390/plants6040061
Received: 2 November 2017 / Revised: 17 November 2017 / Accepted: 30 November 2017 / Published: 6 December 2017
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Abstract
The nitrogen (N) effect of legumes is one of the main reasons for their inclusion in rotation systems and their success in rainfed agriculture of Mediterranean areas. The comparative analysis of this effect in relation to alternative systems or practices is essential for
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The nitrogen (N) effect of legumes is one of the main reasons for their inclusion in rotation systems and their success in rainfed agriculture of Mediterranean areas. The comparative analysis of this effect in relation to alternative systems or practices is essential for a comprehensive appreciation in their merit. This field experiment was comprised of four three-year rotation cycles. Wheat (Triticum turgidum durum) was seeded for two consecutive years after common vetch (Vicia sativa L.), treated in three different ways, and after fallow and compared with three wheat monocultures: the conventional one, the continuous straw incorporation, and the sewage sludge incorporation once every three years. Wheat grain and straw yields and N uptake were compared among treatments. Results showed that rotation systems that included vetch were the most promising for improving sustainability. Maximum N uptake and the greatest yield surpluses were obtained when wheat followed vetch incorporated during flowering. When vetch in the rotation was cut for hay or left to fill grains subsequent wheat showed also enhanced yields. Fallow affected the rotation system’s fertility due to the incorporation of volunteer plants into the soil. Sewage sludge sustained production without the need for inorganic fertilization during three years. Straw incorporation always gave the smallest yields and N harvests, presumably due to soil N immobilization. Full article
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Open AccessArticle Flavonoids and Ellagitannins Characterization, Antioxidant and Cytotoxic Activities of Phyllanthus acuminatus Vahl
Plants 2017, 6(4), 62; doi:10.3390/plants6040062
Received: 8 November 2017 / Revised: 7 December 2017 / Accepted: 8 December 2017 / Published: 15 December 2017
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Abstract
The phenolic composition of leaves from Phyllanthus acuminatus L., a plant commonly used in Costa Rica as traditional medicine, was studied using UPLC-ESI-MS on an enriched phenolic extract. A total of 20 phenolic compounds were identified, comprising eight flavonoids (two flavanones—pinocembrin isomers and
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The phenolic composition of leaves from Phyllanthus acuminatus L., a plant commonly used in Costa Rica as traditional medicine, was studied using UPLC-ESI-MS on an enriched phenolic extract. A total of 20 phenolic compounds were identified, comprising eight flavonoids (two flavanones—pinocembrin isomers and six derivatives from apigenin, chrysin, quercetin, and kaempferol); seven ellagitannins, two flavan-3-ols (prodelphinidin B dimer and (epi)gallocatechin); and three phenolic acids (ellagic acid, trimethylellagic acid, and ferulic acid). All of these compounds are reported for the first time in P. acuminatus, while previously reported in the genus Phyllanthus. Antioxidant evaluation was performed for P. acuminatus phenolic extract obtaining DPPH results with a remarkably low IC50 value of 0.15 μg/mL. Also, cytotoxicity on gastric AGS and colon SW20 adenocarcinoma cell lines was evaluated, and highly promising results were obtained, with IC50 values of 11.3 μg/mL and 10.5 μg/mL, respectively. Furthermore, selectivity index values obtained when comparing cytotoxicity on normal Vero cells was SI > 20 for both cancer cell lines, indicating a particularly high selectivity. Additionally, Justicidin B, a metabolite extensively studied for its antitumoral activity, was isolated from a non-polar extract of P. acuminatus, and comparatively evaluated for both bioactivities. The DPPH value obtained for Justicidin B was moderate (IC50 = 14.28 μg/mL), while cytotoxicity values for both AGS (IC50 = 19.5 μg/mL) and SW620 (IC50 = 24.8 μg/mL) cell lines, as well as selectivity when compared with normal Vero cells (SI = 5.4 and 4.2 respectively), was good, but lower than P. acuminatus extract. These preliminary results suggest that P. acuminatus enriched phenolic extract containing flavonoids, ellagitannins, flavan-3-ols, and phenolic acids, reported for the first time in this plant, could be of interest for further cancer cytotoxicity studies to elucidate structure–bioactivity relationships, and the molecular mechanisms and pathways. Full article
(This article belongs to the Special Issue Plant Flavonoids)
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Open AccessArticle Preserving Traditional Botanical Knowledge: The Importance of Phytogeographic and Ethnobotanical Inventory of Peruvian Dye Plants
Plants 2017, 6(4), 63; doi:10.3390/plants6040063
Received: 1 November 2017 / Revised: 12 December 2017 / Accepted: 12 December 2017 / Published: 18 December 2017
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Abstract
Peru is a megadiverse country with native species of all kinds, including dye plants, which have been used for hundreds of years by the local population. Despite the fact that many of these natural dyes are of a superior quality compared to synthetic
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Peru is a megadiverse country with native species of all kinds, including dye plants, which have been used for hundreds of years by the local population. Despite the fact that many of these natural dyes are of a superior quality compared to synthetic ones and do not have the harmful effects that the latter may cause to human health, due to the lack of documentation and dissemination, ethnobotanical knowledge is unfortunately being lost with the passing of generations. In order to preserve and spread such valuable knowledge, this study conducted a comprehensive taxonomic, phytogeographic, and ethnobotanical inventory of dye plants based on periodical botanical explorations in selected locations of Northern Peru during the span of two decades. A critical review of the specialized bibliography was then carried out and the findings were verified with the personal knowledge and experience of both the researchers and the local and regional people. The results of the inventory record 32 species of dye plants from Northern Peru distributed in 22 families, of which the following stand out due to the number of species: Fabaceae (5), Anacardiaceae (2), Annonaceae (2), Asteraceae (2), Berberidaceae (2), Rosaceae (2), and Solanaceae (2). Of the 32 dye species identified, four are considered endemic from Peru: Berberis buceronis J.F. Macbr., Caesalpinia paipai Ruiz & Pav., Coreopsis senaria S.F. Blake & Sherf., and Lomatia hirsuta (Lam.) Diels. The study also found that species such as Bixa orellana L., Indigofera suffruticosa Mill., Sambucus peruviana, and the lichen Usnea baileyi (Stirton) Zahlbr have not been commercially exploited in Peru despite the fact that they already constitute a great economic source for several countries. Full article
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Open AccessArticle Dead Pericarps of Dry Fruits Function as Long-Term Storage for Active Hydrolytic Enzymes and Other Substances That Affect Germination and Microbial Growth
Plants 2017, 6(4), 64; doi:10.3390/plants6040064
Received: 25 October 2017 / Revised: 30 November 2017 / Accepted: 30 November 2017 / Published: 19 December 2017
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Abstract
It is commonly assumed that dead pericarps of dry indehiscent fruits have evolved to provide an additional physical layer for embryo protection and as a means for long distance dispersal. The pericarps of dry fruits undergo programmed cell death (PCD) during maturation whereby
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It is commonly assumed that dead pericarps of dry indehiscent fruits have evolved to provide an additional physical layer for embryo protection and as a means for long distance dispersal. The pericarps of dry fruits undergo programmed cell death (PCD) during maturation whereby most macromolecules such DNA, RNA, and proteins are thought to be degraded and their constituents remobilized to filial tissues such as embryo and endosperm. We wanted to test the hypothesis that the dead pericarp represents an elaborated layer that is capable of storing active proteins and other substances for increasing survival rate of germinating seeds. Using in gel assays we found that dead pericarps of both dehiscent and indehiscent dry fruits of various plant species including Arabidopsis thaliana and Sinapis alba release upon hydration multiple active hydrolytic enzymes that can persist in an active form for decades, including nucleases, proteases, and chitinases. Proteomic analysis of indehiscent pericarp of S. alba revealed multiple proteins released upon hydration, among them proteases and chitinases, as well as proteins involved in reactive oxygen species (ROS) detoxification and cell wall modification. Pericarps appear to function also as a nutritional element-rich storage for nitrate, potassium, phosphorus, sulfur, and others. Sinapis alba dehiscent and indehiscent pericarps possess germination inhibitory substances as well as substances that promote microbial growth. Collectively, our study explored previously unknown features of the dead pericarp acting also as a reservoir of biological active proteins, and other substances capable of “engineering” the microenvironment for the benefit of the embryo. Full article
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Review

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Open AccessReview Phytochemicals: Extraction, Isolation, and Identification of Bioactive Compounds from Plant Extracts
Plants 2017, 6(4), 42; doi:10.3390/plants6040042
Received: 19 July 2017 / Revised: 17 September 2017 / Accepted: 19 September 2017 / Published: 22 September 2017
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Abstract
There are concerns about using synthetic phenolic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) as food additives because of the reported negative effects on human health. Thus, a replacement of these synthetics by antioxidant extractions from various foods has been
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There are concerns about using synthetic phenolic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) as food additives because of the reported negative effects on human health. Thus, a replacement of these synthetics by antioxidant extractions from various foods has been proposed. More than 8000 different phenolic compounds have been characterized; fruits and vegetables are the prime sources of natural antioxidants. In order to extract, measure, and identify bioactive compounds from a wide variety of fruits and vegetables, researchers use multiple techniques and methods. This review includes a brief description of a wide range of different assays. The antioxidant, antimicrobial, and anticancer properties of phenolic natural products from fruits and vegetables are also discussed. Full article
(This article belongs to the Special Issue Medicinal Plants and Natural Product Research)
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Open AccessFeature PaperReview Flavonoid Profile of the Cotton Plant, Gossypium hirsutum: A Review
Plants 2017, 6(4), 43; doi:10.3390/plants6040043
Received: 2 August 2017 / Revised: 10 September 2017 / Accepted: 19 September 2017 / Published: 25 September 2017
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Abstract
Cotton, Gossypium hirsutum L., is a plant fibre of significant economic importance, with seeds providing an additional source of protein in human and animal nutrition. Flavonoids play a vital role in maintaining plant health and function and much research has investigated the role
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Cotton, Gossypium hirsutum L., is a plant fibre of significant economic importance, with seeds providing an additional source of protein in human and animal nutrition. Flavonoids play a vital role in maintaining plant health and function and much research has investigated the role of flavonoids in plant defence and plant vigour and the influence these have on cotton production. As part of ongoing research into host plant/invertebrate pest interactions, we investigated the flavonoid profile of cotton reported in published, peer-reviewed literature. Here we report 52 flavonoids representing seven classes and their reported distribution within the cotton plant. We briefly discuss the historical research of flavonoids in cotton production and propose research areas that warrant further investigation. Full article
(This article belongs to the Special Issue Plant Flavonoids)
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Open AccessReview Surviving a Dry Future: Abscisic Acid (ABA)-Mediated Plant Mechanisms for Conserving Water under Low Humidity
Plants 2017, 6(4), 54; doi:10.3390/plants6040054
Received: 3 October 2017 / Revised: 29 October 2017 / Accepted: 1 November 2017 / Published: 4 November 2017
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Abstract
Angiosperms are able to respond rapidly to the first sign of dry conditions, a decrease in air humidity, more accurately described as an increase in the vapor pressure deficit between the leaf and the atmosphere (VPD), by abscisic acid (ABA)-mediated stomatal closure. The
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Angiosperms are able to respond rapidly to the first sign of dry conditions, a decrease in air humidity, more accurately described as an increase in the vapor pressure deficit between the leaf and the atmosphere (VPD), by abscisic acid (ABA)-mediated stomatal closure. The genes underlying this response offer valuable candidates for targeted selection of crop varieties with improved drought tolerance, a critical goal for current plant breeding programs, to maximize crop production in drier and increasingly marginalized environments, and meet the demands of a growing population in the face of a changing climate. Here, we review current understanding of the genetic mechanisms underpinning ABA-mediated stomatal closure, a key means for conserving water under dry conditions, examine how these mechanisms evolved, and discuss what remains to be investigated. Full article
(This article belongs to the Special Issue Plant Adaptation to Climate Change)
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Open AccessReview Assembly of the Cutin Polyester: From Cells to Extracellular Cell Walls
Plants 2017, 6(4), 57; doi:10.3390/plants6040057
Received: 26 October 2017 / Revised: 16 November 2017 / Accepted: 16 November 2017 / Published: 18 November 2017
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Abstract
Cuticular matrices covering aerial plant organs or delimiting compartments in these organs are composed of an insoluble hydrophobic polymer of high molecular mass, i.e., cutin, that encompass some cell wall polysaccharides and is filled by waxes. Cutin is a polyester of hydroxy and-or
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Cuticular matrices covering aerial plant organs or delimiting compartments in these organs are composed of an insoluble hydrophobic polymer of high molecular mass, i.e., cutin, that encompass some cell wall polysaccharides and is filled by waxes. Cutin is a polyester of hydroxy and-or epoxy fatty acids including a low amount of glycerol. Screening of Arabidopsis and more recently of tomato (Solanum lycopersicum) mutants allowed the delineation of the metabolic pathway involved in the formation of cutin monomers, as well as their translocation in the apoplast. Furthermore, these studies identified an extracellular enzyme involved in the polymerization of these monomers, i.e., cutin synthase 1 (CUS1), an acyl transferase of the GDSL lipase protein family. By comparing the structure of tomato fruit cutins from wild type and down-regulated CUS1 mutants, as well as with the CUS1-catalyzed formation of oligomers in vitro, hypothetical models can be elaborated on the polymerization of cutins. The polymorphism of the GDSL-lipase family raises a number of questions concerning the function of the different isoforms in relation with the formation of a composite material, the cuticle, containing entangled hydrophilic and hydrophobic polymers, i.e., polysaccharides and cutin, and plasticizers, i.e., waxes. Full article
(This article belongs to the Special Issue The Plant Cuticle)
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Open AccessReview TRANSPARENT TESTA GLABRA 1-Dependent Regulation of Flavonoid Biosynthesis
Plants 2017, 6(4), 65; doi:10.3390/plants6040065
Received: 2 November 2017 / Revised: 2 December 2017 / Accepted: 16 December 2017 / Published: 20 December 2017
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Abstract
The flavonoid composition of various tissues throughout plant development is of biological relevance and particular interest for breeding. Arabidopsis thaliana TRANSPARENT TESTA GLABRA 1 (AtTTG1) is an essential regulator of late structural genes in flavonoid biosynthesis. Here, we provide a review of the
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The flavonoid composition of various tissues throughout plant development is of biological relevance and particular interest for breeding. Arabidopsis thaliana TRANSPARENT TESTA GLABRA 1 (AtTTG1) is an essential regulator of late structural genes in flavonoid biosynthesis. Here, we provide a review of the regulation of the pathway’s core enzymes through AtTTG1-containing R2R3-MYELOBLASTOSIS-basic HELIX-LOOP-HELIX-WD40 repeat (MBW(AtTTG1)) complexes embedded in an evolutionary context. We present a comprehensive collection of A. thaliana ttg1 mutants and AtTTG1 orthologs. A plethora of MBW(AtTTG1) mechanisms in regulating the five major TTG1-dependent traits is highlighted. Full article
(This article belongs to the Special Issue Plant Flavonoids)
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