A win-win scenario for photosynthesis and the plasma membrane H+ pump

In plants, cytosolic and extracellular pH homeostasis are crucial for various physiological processes, including the uptake of macronutrients and micronutrients, cell elongation, cell expansion, and enzyme activity. Proton (H+) gradients and the membrane potential are generated by a H+ pump consisting of an active primary transporter. Plasma membrane (PM) H+-ATPase, a PM-localized H+ pump, plays a pivotal role in maintaining pH homeostasis in plant cells and extracellular regions. PM H+-ATPase activity is regulated by protein abundance and by post-translational modifications. Several stimuli have been found to activate the PM H+-ATPase through phosphorylation of the penultimate threonine (Thr) of the carboxy terminus. Light- and photosynthesis-induced phosphorylation of PM H+-ATPase are conserved phenomena among various plant species. In this work, we review recent findings related to PM H+-ATPase regulation in the photosynthetic tissues of plants, focusing on its mechanisms and physiological roles. The physiological roles of photosynthesis-dependent PM H+-ATPase activation are discussed in the context of nitrate uptake and cytoplasmic streaming in leaves.

Antiviral and Antibacterial Effect of Honey Enriched with Rubus spp. as a Functional Food with Enhanced Antioxidant Properties

The aim of this study was to investigate the effect of blackberry and raspberry fruits (1 and 4%) and leaves (0.5 and 1%) on the biological activities of rape honey. Honey and plant material extracts were analyzed regarding total phenolic, flavonoid, anthocyanin contents, HPTLC and HPLC polyphenol profiles, as well as antioxidant activity. The antiviral potential was analyzed against bacteriophage phi 6-a coronavirus surrogate-whereas antimicrobial was tested against S. aureus and E. coli. Blackberry extracts were more abundant in antioxidants than raspberry extracts, with better properties found for leaves than fruits and for cultivated rather than commercial plants. The addition of both Rubus plant additives significantly increased the antioxidant potential of honey by four-fold (for 4% fruits additive) to five-fold (for 1% of leaves). Honey with the addition of fruits possessed higher antiviral potential compared with raw rape honey (the highest for 4% of raspberry fruit and 1% of blackberry leaf additive). Honey enriched with Rubus materials showed higher antibacterial potential against S. aureus than rape honey and effectively inhibited S. aureus biofilm formation. To summarize, honey enriched with Rubus fruit or leaves are characterized by increased pro-health value and can be recommended as a novel functional food.

Two new quinic acid derivatives from the leaves of Schisandra chinensis

Two new (1-2) and three known quinic acid derivatives (3-5) were isolated from the leaves of Schisandra chinensis (Turcz) Baill. The structures of the compounds were determined by spectroscopic methods, especially the NMR techniques, and also by comparison with reported data in the literature. The cytotoxicity activities of these compounds were evaluated on human tumor cell lines LN229 and three of them showed a certain activity.

[Content correlation of eight phenolic acids and flavonoids in different medicinal parts of PA-type Perilla germplasms]

In this study, 10 PA-type Perilla germplasms were selected to detect the content of two phenolic acids, i.e., rosmarinic acid(RA) and caffeic acid(CA), and six flavonoids, including scutellarin-7-O-diglucuronoside(SDG), luteolin-7-O-diglucuronoside(LDG), apigenin-7-O-diglucuronoside(ADG), scutellarin-7-O-glucuroside(SG), luteolin-7-O-glucuroside(LG), and apigenin-7-O-glucuroside(AG) in leaves, stems, and fruits. The total content of phenolic acids and flavonoids in leaves was 3.991-12.028 mg·g~(-1) and 12.309-25.071 mg·g~(-1), respectively, which was much higher than that in stems(0.586-2.015 mg·g~(-1) and 0.879-1.413 mg·g~(-1), respectively) and fruits(0.004-2.222 mg·g~(-1) and 0.651-1.936 mg·g~(-1), respectively). RA was detected in five fruit samples, and RA content between leaves and fruits showed a significant negative correlation in the other five samples. For flavonoids, only LG and LDG could be detected in stems, and SG and SDG were not detected in fruits, while other flavonoids were not detected in some samples. The content of total flavonoids and LG in leaves and fruits was significantly positively correlated, and the content of LG in stems and fruits was significantly positively correlated. In 10 stem samples, seven met the standard that the content of RA in the stem should be not less than 0.1% specified in the Chinese Pharmacopoeia(2020 edition). Only one fruit sample reached the standard of RA content in the fruit not less than 0.25% specified in the Chinese Pharmacopoeia.

Differential Nutrition-Health Properties of Ocimum basilicum Leaf and Stem Extracts

(1) Background: Ocimum basilicum L. is an aromatic medicinal plant of the Lamiaceae family known as sweet basil. It is used in traditional medicine for its beneficial effects on gastrointestinal disorders, inflammation, immune system, pyrexia or cancer among others. Ocimum basilicum (OB) leaf extracts contain many phytochemicals bearing the plant health effects but no reports is available on the potential bioactivity of stem extracts. Our investigation aimed at assessing the differential biological activity between basil leaf and stem to promote this co-product valorization. (2) Method: For this purpose we explored phytochemical composition of both parts of the plant. Antioxidant activity was evaluated through total polyphenol content measure, DPPH and ORAC tests. Anti-inflammatory markers on stimulated macrophages, including NO (nitric oxide), TNFa (tumor necrosis factor alpha), IL-6 (interleukin 6), MCP1 (monocyte attractant protein 1) and PGE-2 (prostaglandin E2), were evaluated. In addition, we investigated OB effects on jejunum smooth muscle contractility. (3) Results: OB extracts from leaves and stems demonstrated a different biological activity profile at the level of both antioxidant, anti-inflammatory and smooth muscle relaxation effects. (4) Conclusion: Taken together our results suggest that Ocimum basilicum extracts from co-product stems, in addition to leaves, may be of interest at the nutrition-health level with specific therapeutic potential.

Chemical analysis, antifungal and antimycotoxigenic activity of tetradenia riparia essential oil and crude extract

Tetradenia riparia is known for its richness in essential oil which has been widely investigated due to its biological activities such as antimicrobial, insecticidal, trypanocidal, antimalarial and antioxidant. The objective of this work was to chemically analyze and evaluate the antifungal and antimycotoxigenic activity of the essential oil and the crude extract of leaves, flower buds and stems of T. riparia from the northwest region of the state of Paraná. The essential oil was obtained by hydrodistillation using a Clevenger-type apparatus. To obtain the crude extract, the leaves, flower buds and stems were pulverized and subjected to a dynamic maceration process using 70% v v^-1 ethyl alcohol. Chemical analysis of the essential oil was performed by GC/MS, and chemical identification of the crude extract by UHPLC-ESI/qTOF. Antifungal activity (Rhizopus oryzae, Aspergillus flavus, Aspergillus ochraceus, Penicillium verrucosum and Fusarium graminearum) was performed by broth microdilution and the antimycotoxigenic assay was performed with A. ochraceus and P. verrucosum. Ochratoxin A was extracted by partition with chloroform and quantified by HPLC-FL. The oil yield was 0.29% for leaves, 0.34% for stems and 0.38% for flower buds, and the major compounds were fenchone, β-caryophyllene, α-cadinol, 14-hydroxy-9- epi-caryophyllene, 9β,13β-epoxy-7-abietene, α-cadinol and 6-7-dehydroroyleanone. The main chemical compounds identified in the crude extract were terpenes, anthocyanins, flavonoids, tannins and phenolic acids. The minimum inhibitory concentration (MIC) of oils from leaves, flower buds and stems for the strains tested ranged from 0.87 mg mL^-1 to 33.3 mg mL^-1, while the minimum fungicidal concentration (MFC) ranged from 6.94 mg mL^-1 and 33.3 mg mL^-1. The MIC and MFC for ketoconazole, tebuconazole, sorbate and nitrite ranged from 0.05 to 33.3 mg mL^-1. The oil and crude extract of leaves, stems and flower buds showed an inhibition of ochratoxin A production for P. verrucosum of approximately 100%.

The Effect of Standardised Leaf Extracts of Gaultheria procumbens on Multiple Oxidants, Inflammation-Related Enzymes, and Pro-Oxidant and Pro-Inflammatory Functions of Human Neutrophils

The leaves of Gaultheria procumbens are polyphenol-rich traditional medicines used to treat inflammation-related diseases. The present study aimed to optimise the solvent for the effective recovery of active leaf components through simple direct extraction and verify the biological effects of the selected extract in a model of human neutrophils ex vivo. The extracts were comprehensively standardised, and forty-one individual polyphenols, representing salicylates, catechins, procyanidins, phenolic acids, and flavonoids, were identified by UHPLC–PDA–ESI–MS³. The chosen methanol–water (75:25, v/v) extract (ME) was obtained with the highest extraction yield and total phenolic levels (397.9 mg/g extract’s dw), including 98.9 mg/g salicylates and 299.0 mg/g non-salicylate polyphenols. In biological tests, ME revealed a significant and dose-dependent ability to modulate pro-oxidant and pro-inflammatory functions of human neutrophils: it strongly reduced the ROS level and downregulated the release of pro-inflammatory cytokines and tissue remodelling enzymes, especially IL-1β and elastase 2, in cells stimulated by fMLP, LPS, or fMLP + cytochalasin B. The extracts were also potent direct scavengers of in vivo relevant oxidants (O₂^•−, ^•OH, and H₂O₂) and inhibitors of pro-inflammatory enzymes (cyclooxygenase-2, hyaluronidase, and lipoxygenase). The statistically significant correlations between the tested variables revealed the synergic contribution of individual polyphenols to the observed effects and indicated them as useful active markers for the standardisation of the extract/plant material. Moreover, the safety of ME was confirmed in cytotoxicity tests. The obtained results might partially explain the ethnomedicinal application of G. procumbens leaves and support the usage of the standardised leaf extract in the adjuvant treatment of oxidative stress and inflammation-related chronic diseases.

Molecular and Physiological Responses of Citrus sinensis Leaves to Long-Term Low pH Revealed by RNA-Seq Integrated with Targeted Metabolomics

Low pH-induced alterations in gene expression profiles and organic acids (OA) and free amino acid (FAA) abundances were investigated in sweet orange [Citrus sinensis (L.) Osbeck cv. Xuegan] leaves. We identified 503 downregulated and 349 upregulated genes in low pH-treated leaves. Further analysis indicated that low pH impaired light reaction and carbon fixation in photosynthetic organisms, thereby lowering photosynthesis in leaves. Low pH reduced carbon and carbohydrate metabolisms, OA biosynthesis and ATP production in leaves. Low pH downregulated the biosynthesis of nitrogen compounds, proteins, and FAAs in leaves, which might be conducive to maintaining energy homeostasis during ATP deprivation. Low pH-treated leaves displayed some adaptive responses to phosphate starvation, including phosphate recycling, lipid remodeling, and phosphate transport, thus enhancing leaf acid-tolerance. Low pH upregulated the expression of some reactive oxygen species (ROS) and aldehyde detoxifying enzyme (peroxidase and superoxidase) genes and the concentrations of some antioxidants (L-tryptophan, L-proline, nicotinic acid, pantothenic acid, and pyroglutamic acid), but it impaired the pentose phosphate pathway and V_E and secondary metabolite biosynthesis and downregulated the expression of some ROS and aldehyde detoxifying enzyme (ascorbate peroxidase, aldo-keto reductase, and 2-alkenal reductase) genes and the concentrations of some antioxidants (pyridoxine and γ-aminobutyric acid), thus disturbing the balance between production and detoxification of ROS and aldehydes and causing oxidative damage to leaves.

Developmental regulation of leaf venation patterns: monocot versus eudicots and the role of auxin

Organisation and patterning of the vascular network in land plants varies in different taxonomic, developmental and environmental contexts. In leaves, the degree of vascular strand connectivity influences both light and CO₂ harvesting capabilities as well as hydraulic capacity. As such, developmental mechanisms that regulate leaf venation patterning have a direct impact on physiological performance. Development of the leaf venation network requires the specification of procambial cells within the ground meristem of the primordium and subsequent proliferation and differentiation of the procambial lineage to form vascular strands. An understanding of how diverse venation patterns are manifest therefore requires mechanistic insight into how procambium is dynamically specified in a growing leaf. A role for auxin in this process was identified many years ago, but questions remain. In this review we first provide an overview of the diverse venation patterns that exist in land plants, providing an evolutionary perspective. We then focus on the developmental regulation of leaf venation patterns in angiosperms, comparing patterning in eudicots and monocots, and the role of auxin in each case. Although common themes emerge, we conclude that the developmental mechanisms elucidated in eudicots are unlikely to fully explain how parallel venation patterns in monocot leaves are elaborated.

In-Field Wheat Reflectance: How to Reach the Organ Scale?

The reflectance of wheat crops provides information on their architecture or physiology. However, the methods currently used for close-range reflectance computation do not allow for the separation of the wheat canopy organs: the leaves and the ears. This study details a method to achieve high-throughput measurements of wheat reflectance at the organ scale. A nadir multispectral camera array and an incident light spectrometer were used to compute bi-directional reflectance factor (BRF) maps. Image thresholding and deep learning ear detection allowed for the segmentation of the ears and the leaves in the maps. The results showed that the BRF measured on reference targets was constant throughout the day but varied with the acquisition date. The wheat organ BRF was constant throughout the day in very cloudy conditions and with high sun altitudes but showed gradual variations in the morning under sunny or partially cloudy sky. As a consequence, measurements should be performed close to solar noon and the reference panel should be captured at the beginning and end of each field trip to correct the BRF. The method, with such precautions, was tested all throughout the wheat growing season on two varieties and various canopy architectures generated by a fertilization gradient. The method yielded consistent reflectance dynamics in all scenarios.

Carbon and Nitrogen Metabolism Are Jointly Regulated During Shading in Roots and Leaves of Camellia Sinensis

Numerous studies have shown that plant shading can promote the quality of green tea. However, the association of shading with metabolic regulation in tea leaves and roots remains unelucidated. Here, the metabolic profiling of two tea cultivars ("Xiangfeicui" and "Jinxuan") in response to shading and relighting periods during the summer season was performed using non-targeted metabolomics methods. The metabolic pathway analyses revealed that long-term shading remarkably inhibit the sugar metabolism such as glycolysis, galactose metabolism, and pentose phosphate pathway in the leaves and roots of "Xiangfeicui," and "Jinxuan" were more sensitive to light recovery changes. The lipid metabolism in the leaves and roots of "Xiangfeicui" was promoted by short-term shading, while it was inhibited by long-term shading. In addition, the intensity of the flavonoid metabolites in the leaves and roots of "Jinxuan" were upregulated with a trend of rising first and then decreasing under shading, and five flavonoid synthesis genes showed the same trend (F3H, F3'5'H, DFR, ANS, and ANR). Simultaneously, the amino acids of the nitrogen metabolism in the leaves and roots of the two cultivars were significantly promoted by long-term shading, while the purine and caffeine metabolism was inhibited in the leaves of "Xiangfeicui." Interestingly, CsGS1.1 and CsTSI, amino acid synthase genes was upregulated in the leaves and roots of two cultivars. These results indicated that shading could participate in carbon and nitrogen metabolic regulation of both leaf and root, and root metabolism could have a positive association with leaf metabolism to promote the shaded tea quality.

Red Horse Chestnut and Horse Chestnut Flowers and Leaves: A Potential and Powerful Source of Polyphenols with High Antioxidant Capacity

Aesculus flowers and leaves are an excellent source of bioactive compounds, including flavanols, phenolic acids, and anthocyanins, and the leaves also contain antioxidant carotenoids and chlorophylls. The aim of this study was to analyse and compare the amounts of bioactive compounds present in Aesculus hippocastanum and Aesculus × carnea flowers and leaves over two years. These two species from six independent locations (parks and green areas) located in Warsaw were assessed in this study. The dry matter by the scale method and polyphenol, carotenoid, and chlorophyll content by the HPLC method of the flowers and leaves was evaluated. Red horse chestnut flowers contained significantly more total carotenoids (40.6 µg/g FW) and chlorophylls (36.9 µg/g FW) than horse chestnut flowers, and red horse chestnut flowers contained higher levels of anthocyanins (5.41 µg/g FW) than other species. We observed that horse chestnut flowers were characterized by a higher total polyphenols concentration (9.45 µg/g FW) compared to red horse chestnut flowers. In addition, the analysis of leaves showed that all quality parameters were higher in red horse chestnut species. Five individual anthocyanins were identified in both species’ flowers, but a higher concentration was found in red horse chestnut flowers, and pelargonidin-3-O-glucoside was the predominant form among a pool of total anthocyanins. In both experimental years, leaves (109.25 mMol/100 g FW and 112.0 mMol/100 g FW) were characterized by a higher antioxidant activity than flowers (27.0 mMol/100 g FW and 27.5 mMol/100 g FW).

Visualizing the effect of freezing on the vascular system of wheat in 3 dimensions by in-block imaging of dye-infiltrated plants

Infrared thermography has shown after roots of grasses freeze, ice spreads into the crown and then acropetally into leaves initially through vascular bundles. Leaves freeze singly with the oldest leaves freezing first and the youngest freezing later. Visualising the vascular system in its native 3‐dimensional state will help in the understanding of this freezing process. A 2 cm section of the crown that had been infiltrated with aniline blue was embedded in paraffin and sectioned with a microtome. A photograph of the surface of the tissue in the paraffin block was taken after the microtome blade removed each 20 μm section. Two hundred to 300 images were imported into Adobe After Effects and a 3D volume of the region infiltrated by aniline blue dye was constructed. The reconstruction revealed that roots fed into what is functionally a region inside the crown that could act as a reservoir from which all the leaves are able to draw water. When a single root was fed dye solution, the entire region filled with dye and the vascular bundles of every leaf took up the dye; this indicated that the vascular system of roots was not paired with individual leaves. Fluorescence microscopy suggested the edge of the reservoir might be composed of phenolic compounds. When plants were frozen, the edges of the reservoir became leaky and dye solution spread into the mesophyll outside the reservoir. The significance of this change with regard to freezing tolerance is not known at this time.

Thermal cameras that allow visualisation of water freezing in plants have shown that in crops like wheat, oats and barley, ice forms first at the bottom of the plant and then moves upwards into leaves through water conducting channels. Leaves freeze one at a time with the oldest leaves freezing first and then younger ones further up the stem freeze later. To better understand why plants freeze like this, we reconstructed a 3‐dimensional view of the water conducting channels. After placing the roots of a wheat plant in a blue dye and allowing it to pull the dye upwards into leaves, we took a part of the stem just above the roots and embedded it in paraffin. We used a microtome to slice a thin layer of the paraffin containing the plant and then photographed the surface after each layer was removed. After taking about 300 images, we used Adobe After Effects software to re‐construct the plant with the water conducting system in three dimensions. The 3D reconstruction showed that roots fed into a roughly spherical area at the bottom of the stem that could act as a kind of tank or reservoir from which the leaves pull up water. When we put just one root in dye, the entire reservoir filled up and the water conducting channels in every leaf took up the dye. This indicates that the water channels in roots were not directly connected to specific leaves as we had thought. When plants were frozen, the dye leaked out of the reservoir and spread into cells outside. Research is continuing to understand the significance of this change during freezing. It is possible that information about this effect can be used to help breeders develop more winter‐hardy crop plants.

Leaf Polyphenolic Profile as a Determinant of Croatian Native Grapevine Varieties' Susceptibility to Plasmopara viticola

Since grapevine is highly susceptible to various pathogens, enormous amounts of pesticides are applied each season to achieve profitable production. One of the most destructive grapevine diseases is downy mildew, and their interaction has been in the spotlight for more than a decade. When it comes to a metabolome level, phenolic compounds are relevant to investigate due to their involvement in the plant immune system and known antifungal properties. Croatian grapevine germplasm is highly heterogeneous due to its long history of cultivation in diversified geographical regions. Since it has been found that native varieties react differently to the infection of Plasmopara viticola, the intention of this study is to define if the chemical background of the leaves, i.e., polyphenolic composition, is responsible for these dissimilarities. Therefore, the leaves of 17 genotypes, among which 14 were native and 3 were controls, were analyzed using high-performance liquid chromatography (HPLC) in four terms: before inoculation and 24, 48, and 96 h post inoculation (hpi). During this early phase, significant differences were found neither between the terms nor between the non-inoculated and inoculated samples, except for resveratrol-3-O-glucoside. By applying principal component analysis (PCA) using initial leaf polyphenolic composition, varieties of V. vinifera were clearly separated into three different groups corresponding to their International Organization of Vine and Wine (OIV) classes of susceptibility to P. viticola. Results obtained in this research suggest that the initial constitutive polyphenolic composition of the cultivar leaves has a crucial influence on their susceptibility to P. viticola, and this finding can be used to improve the success of grapevine breeding programs toward downy mildew resistance.

Effects of phenotypic variability on the oxygen and hydrogen isotope compositions of grains in different winter wheat varieties

Stable isotope analyses are the leading method for geographic origin determination, especially of plant-based agricultural products. Origin analysis is typically done by comparing a suspicious sample to reference materials with known geographic origin. Reference materials are usually collected at the species level, assuming different varieties of a species to have comparable isotope compositions within a given location. We evaluated whether different phenotypes that are expressed in different varieties of winter wheat (Triticum aestivum L.) influence the oxygen (δ¹⁸O) and hydrogen (δ²H) isotope composition of plant tissue water and organic compounds. We found that mean δ¹⁸O and δ²H values among winter wheat varieties did not differ significantly in leaf water, however, differed significantly in bulk dried grain tissue. The differences in bulk dried grain δ¹⁸O and δ²H values among varieties can be related to differences in phenotypic trait expression among varieties. Despite this substantial phenotypic variability, the overall variability of bulk dried grain δ¹⁸O and δ²H values among varieties was small (SD 0.54 ‰ for oxygen, 3.60 ‰ for hydrogen). We thus conclude that reference materials collected at the species level should be sufficient for geographic origin analysis of winter wheat and possibly other cereals using δ¹⁸O and δ²H values.

When rain collides with plants-patterns and forces of drop impact and how leaves respond to them

Raindrop impact on leaves is a common event which is of relevance for numerous processes, including the dispersal of pathogens and propagules, leaf wax erosion, gas exchange, leaf water absorption, and interception and storage of rainwater by canopies. The process of drop impact is complex, and its outcome depends on many influential factors. The wettability of plants has been recognized as an important parameter which is itself complex and difficult to determine for leaf surfaces. Other important parameters include leaf inclination angle and the ability of leaves to respond elastically to drop impact. Different elastic motions are initiated by drop impact, including local deformation, flapping, torsion, and bending, as well as 'swinging' of the petiole. These elastic responses, which occur on different time scales, can affect drop impact directly or indirectly, by changing the leaf inclination. An important feature of drop impact is splashing, meaning the fragmentation of the drop with ejection of satellite droplets. This process is promoted by the kinetic energy of the drop and leaf traits. For instance, a dense trichome cover can suppress splashing. Basic drop impact patterns are presented and discussed for a number of different leaf types, as well as some exemplary mosses.

Effect of Artichoke (cynara scolymus) on cardiac markers, lipid profile and antioxidants levels in tissue of HFD-induced obesity

Obesity plays a pivotal role in the insulin resistance disease, which is related to hypertension, hyperlipidemia, type 2 diabetes mellitus, and an increased risk of cardiovascular disease. The purpose of the present study was done to evaluate the effect of artichoke leaves extract (ALE) in the high-fat diet (HFD)-induced cellular obesity and cardiac damage in Wistar rats. Body and organ weights, serum lipid profile, cardiac markers, and antioxidants enzymes were measured. Oral administration of ALE at two doses 200 and 400 mg/kg for a period of 60 days showed a significant decrease in body and organ weights, serum total cholesterol, triglycerides, LDH, ALT accompanied by decreasing in oxidative stress biomarker (MDA, and AOPP) and increasing antioxidant enzymes (SOD, CAT, and GPx) levels as compared to HFD groups. The histological findings showed a cardioprotective effect of ALE. These findings suggest that ALE exert anti-oxidant cardiac effects in HFD- induced obese rats.

Nutritional Value and Bioactive Compounds of Leaves and Grains from Quinoa (Chenopodium quinoa Willd.)

Quinoa is an important crop for food security and food sovereignty in Ecuador. In this study, we evaluated the nutritional value, bioactive compounds, and antinutrient compounds of leaves and grains of the Ecuadorian quinoa variety Tunkahuan, and we identified significant differences between the nutrient content in the leaves and grains. The quinoa leaves presented a higher protein content than the grains, as well as inorganic nutrients such as calcium, phosphorus, iron, and zinc. Both the grains and leaves had an appreciable phenolic content. In addition, the quinoa grains presented a higher content of the antinutrient saponin than the leaves, while the leaves contained more nitrates and oxalates than the grains. Thus, quinoa leaves and grains exhibit excellent potential for application in the food and pharmaceutical industries.

Plant Flavonoids in Mediterranean Species: A Focus on Flavonols as Protective Metabolites under Climate Stress

Flavonoids are specialized metabolites largely widespread in plants where they play numerous roles including defense and signaling under stress conditions. These compounds encompass several chemical subgroups such as flavonols which are one the most represented classes. The most studied flavonols are kaempferol, quercetin and myricetin to which research attributes antioxidative properties and a potential role in UV-defense through UV-screening mechanisms making them critical for plant adaptation to climate change. Despite the great interest in flavonol functions in the last decades, some functional aspects remain under debate. This review summarizes the importance of flavonoids in plant defense against climate stressors and as signal molecules with a focus on flavonols in Mediterranean plant species. The review emphasizes the relationship between flavonol location (at the organ, tissue and cellular scales) and their function as defense metabolites against climate-related stresses. It also provides evidence that biosynthesis of flavonols, or flavonoids as a whole, could be a crucial process allowing plants to adapt to climate change, especially in the Mediterranean area which is considered as one of the most sensitive regions to climate change over the globe.

Effectivity of hand soap gel ethanol extract acem acem leaves (Oxalis dehradunensis Raizada) as pesticide cleaner: Experimental study in Indonesian farmers

The Karo's farmers use the plant as a substitute for water and soap called acem acem (Oxalis dehradunensis Raizada) leaves to clean the direct pesticide exposure at their skin. This study was aimed to determine the effective formula of Oxalis dehradunensis Raizada leaves extract as hand soap gel preparation to remove pesticide residues. The experimental research was conducted to explore the potential of the leaves as an alternative material for pesticide cleaner. It is a pre and post experiment that was tried by 30 farmers from Karo district, Indonesia. The material used fresh Oxalis dehradunensis Raizada leaves, collected from farmer's fields. The extract was gained from the leaves powder was repeatedly extracted by maceration. All farmers used a pesticide with chlorpyrifos content and wash their hands by using handsoap gel extract ethanol Oxalis dehradunensis Raizada formula. The water of the farmer's hand wash was check-in the laboratory for screened phytochemicals. The data were analyzed in quantitative and gas chromatography to find the ability of the extract to remove chlorpyrifos pesticide residues, in the farmer's hand wash water as a qualitative test. The results found that Oxalis dehradunensis Raizada was formulated into hand soap gel could remove chlorpyrifos pesticide residue from hand wash of the farmers. The ability of hand soap gel with Oxalis dehradunensis Raizada concentration of 5% and 7% in binding residue compounds of chlorpyrifos pesticides was considered good. It concluded the Oxalis dehradunensis Raizada leaves are effective to clean the pesticide residues.

Early spring flowers rely on xylem hydration but are not limited by stem xylem conductivity

Many woody plants produce large floral displays early in the spring when xylem transport can be variable and often reduced. To determine whether stem hydraulics impact floral water use, we quantified floral transpiration and tested whether it was correlated with stem xylem conductivity in five temperate woody species that flower before producing leaves. We measured inflorescence gas exchange, examined the relationship between diffusive conductance and inflorescence morphology, and estimated the amount of water supplied to an inflorescence by the phloem. We also tested for correlation between transpiration and native stem xylem conductivity for branches with leaves and branches with flowers. The flowers of our study species obtain most of their water from the xylem. Diffusive conductance was higher in small inflorescences, but water content and daily transpiration rates were greater for larger inflorescences. We found no correlation between floral transpiration per branch and stem xylem conductivity within species. The data suggest that inflorescence water loss during anthesis is not limited by the xylem in our study species. We highlight the impact of floral morphology on hydraulic traits and encourage exploration into temporal shifts in floral hydration.

Blackberry Leaves as New Functional Food? Screening Antioxidant, Anti-Inflammatory and Microbiological Activities in Correlation with Phytochemical Analysis

Blackberry fruits are recognized as functional foods while blackberry leaves are outside this classification and they also contain active compounds with health-promoting potential. Therefore, the aim of this study was the phytochemical analysis of blackberry leaves of varieties (Chester, Loch Ness, Loch Tay and Ruczaj) and screening of their biological activity (antioxidant potential, possibility of inhibition of enzymes, anti-inflammatory and microbial activity). The following compounds from selected groups: phenolic acids (caffeic acid, ellagic acid, gallic acid, syringic acid), flavonols (quercetin, kaempferol) and their glycosides (rutin, isoquercetin, hyperoside) and flavon-3-ols (catechin, epicatechin) were chromatographically determined in the aqueous and hydroalcoholic leaves extracts. All tested blackberry leaves extracts showed antioxidant effects, but the highest compounds content (TPC = 101.31 mg GAE/g) and antioxidant activity (e.g., DPPH IC₅₀ = 57.37 μg/mL; ABTS IC₅₀ = 24.83 μg/mL; CUPRAC IC₅₀ = 62.73 μg/mL; FRAP IC₅₀ = 39.99 μg/mL for hydroalcoholic extracts) was indicated for the Loch Tay variety. Blackberry leaf extracts’ anti-inflammatory effect was also exceptionally high for the Loch Tay variety (IC₅₀ = 129.30 μg/mL), while leaves extracts of the Loch Ness variety showed a significant potential for microbial activity against Lactobacillus spp. and Candida spp. Summarizing, the best multidirectional pro-health effect was noted for leaves extracts of Loch Tay variety.

Influence of Plant Origins and Seasonal Variations on Nutritive Values, Phenolics and Antioxidant Activities of Adenia viridiflora Craib., an Endangered Species from Thailand

Adenia viridiflora Craib. is an indigenous plant found in Thailand, Cambodia and Vietnam that has become threatened owing to lack of knowledge about its agricultural management. This plant is now rare in the wild and was registered in the Plant Genetic Conservation Project under the initiation of Her Royal Highness Princess Maha Chakri Sirindhorn (RSPG) to promote sustainable conservation and optimally beneficial utilization. A. viridiflora has a long history of utilization as a nutrient-rich source with medicinal properties but scientific evidence of the veracity of these claims is limited. Here, the nutritional compositions, phenolic contents and antioxidant activities of different plant parts (young shoots and old leaves) of A. viridiflora were investigated using plants collected from four areas of Thailand as Kamphaeng Phet (KP), Muang Nakhon Ratchasima (MN), Pakchong Nakhon Ratchasima (PN) and Uthai Thani (UT) at different harvesting periods (March-April, May–June and July–August). Results indicated that young shoots provided higher energy, protein, fat, dietary fiber, phosphorus, sodium, and zinc than old leaves. By contrast, nutrients such as total sugar, vitamin C, carotenoids, potassium, calcium, magnesium, and iron contents were higher in old leaves that also exhibited higher phenolic contents and most antioxidant activities than young shoots. Generally, most nutrients, phenolic contents, and antioxidant activities exhibited no clear trend among different plant origins. The harvesting period of July–August provided a suitable climate for biosynthesis of most nutrients, while high phenolics were mainly found in samples harvested in March–April. No clear trend was observed in the prevalence of antioxidant activities that varied according to assay techniques.

Adaptive Responses of Citrus grandis Leaves to Copper Toxicity Revealed by RNA-Seq and Physiology

Copper (Cu)-toxic effects on Citrus grandis growth and Cu uptake, as well as gene expression and physiological parameters in leaves were investigated. Using RNA-Seq, 715 upregulated and 573 downregulated genes were identified in leaves of C. grandis seedlings exposed to Cu-toxicity (LCGSEC). Cu-toxicity altered the expression of 52 genes related to cell wall metabolism, thus impairing cell wall metabolism and lowering leaf growth. Cu-toxicity downregulated the expression of photosynthetic electron transport-related genes, thus reducing CO₂ assimilation. Some genes involved in thermal energy dissipation, photorespiration, reactive oxygen species scavenging and cell redox homeostasis and some antioxidants (reduced glutathione, phytochelatins, metallothioneins, l-tryptophan and total phenolics) were upregulated in LCGSEC, but they could not protect LCGSEC from oxidative damage. Several adaptive responses might occur in LCGSEC. LCGSEC displayed both enhanced capacities to maintain homeostasis of Cu via reducing Cu uptake by leaves and preventing release of vacuolar Cu into the cytoplasm, and to improve internal detoxification of Cu by accumulating Cu chelators (lignin, reduced glutathione, phytochelatins, metallothioneins, l-tryptophan and total phenolics). The capacities to maintain both energy homeostasis and Ca homeostasis might be upregulated in LCGSEC. Cu-toxicity increased abscisates (auxins) level, thus stimulating stomatal closure and lowering water loss (enhancing water use efficiency and photosynthesis).