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Arsenic catastrophe has caused serious health hazards to the exposed population. An estimated 10 million people are exposed to arsenic poisoning through groundwater. The arsenic contamination through ground water has caused health diseases such as skin manifestations, loss of appetite, nausea, bowel disorders, neurological disorders etc. Therefore, there is need for search for proper therapeutic drug against arsenic induced toxicity in rats. In the present study, arsenic induced toxic model was developed by treating Charles Foster rats (n=18) with sodium arsenite orally at the dose of 8 mg/kg body weight daily for 60 days followed by administration of Bacopa moneri (Brahmi) leaf extract at the dose of 30mg/kg body weight daily by gavage method for 60 days. After the completion of the experiment, all the animals were sacrificed and their blood samples were collected along with their vital tissues. Following parameters were assayed such as haematological assay, biochemical assay and histopathological evaluation in the present study. The haematological study comprised of RBC counts, WBC counts, platelets counts and heamoglobin percentage. For biochemical evaluation, the liver function test and the kidney function test parameters along with free radical assay were carried out. The histopathological study also showed very high degree of degeneration in the hepatocytes and the nephrocytes in the vital organ's liver and kidney. But, after the administration of ethanolic leaf extract of Bacopa moneri, there was marked restoration in the studied parameters. The haematological parameters, the biochemical parameters as well as the histopathological study showed very significant outcomes. Therefore, the present studied medicinal plant Bacopa moneri possesses antidote effect against arsenic induced toxicity in Charles Foster rats which can be used as therapeutic drug in the future after clinical approval. [ABSTRACT FROM AUTHOR]

Behavior and fitness are important ecological traits frequently measured in insect bioassays. A common method to measure them in soft‐bodied herbivorous insects involves confining individuals to plant leaves using clip cages. Although studies have previously highlighted the negative effects of clip cages on leaf physiology, little is known about the impact that using this confinement method has on insect fitness. The responses of different aphid genotypes/clones to different containment methods have not previously been investigated. Here we measured key fitness traits (intrinsic rate of natural increase, mean relative growth rate, time to reach reproductive adulthood and population doubling time) in the potato aphid, Macrosiphum euphorbiae Thomas (Hemiptera: Aphididae), when confined to plants using two methods: (1) clip cages to confine aphids to individual strawberry leaves and (2) a mesh bag to confine aphids to whole strawberry plants. Our study identified a strong negative impact on all the measured aphid fitness traits when using clip cages instead of mesh bags. We also identified genotype‐specific differences in response to confinement method, where clip cage confinement differentially affected the fitness of a given aphid genotype compared to the same genotype on whole plants. These results suggest that clip cage use should be carefully considered when experiments seek to quantify insect fitness and that whole plants should be used wherever possible. Given the prevalence of clip cage use in insect bioassays, our results highlight the need for caution when interpreting the existing literature as confinement method significantly impacts aphid fitness depending on their genotype. [ABSTRACT FROM AUTHOR]

The present study focused on three autochthonous varieties of apple trees belonging to the old Tuscany germplasm (central Italy), Chitignano, Mora and Ruggine, and aimed to (a) evaluate the presence of the four main latent viruses of apple trees (apple chlorotic leaf spot virus [ACLSV], apple mosaic virus [ApMV], apple stem grooving virus [ASGV] and apple stem pitting virus [ASPV]) and (b) elucidate the biochemical and physiological responses of apple leaves and fruits challenged by ACLSV (the only virus detected). Indeed, despite no visible symptoms being reported, more than half of the assayed trees tested positive for ACLSV, although it occurred only in Mora and Ruggine. ACLSV impaired the photosynthetic performance of apple trees, especially in Ruggine leaves, but variety‐specific responses in terms of reorganization of photosynthetic pigment and primary metabolites were reported. Mora showed a higher ability to trigger the de‐epoxidation state of xanthophylls and to accumulate α‐tocopherol, while d‐glucose and sucrose increased only in infected Ruggine leaves, probably as a signalling response and/or an osmotic adjustment of this variety under ACLSV infection. Unexpectedly, ACLSV infection slightly increased pome size, but it dramatically reduced their quality (i.e., soluble solids content), again especially in Ruggine, the only variety where reductions of d‐fructose, d‐glucose and malic acid contents were reported. Overall, the evidence here reported could offer valuable insights to effectively cope with the detrimental viral diseases affecting this species and to protect the production of one of the most consumed and appreciated fruits in the world. [ABSTRACT FROM AUTHOR]

Water‐saving and drought‐resistant rice (WDR) coupled with alternate wetting and drying irrigation (AWDI) possesses a high photosynthetic potential due to higher mesophyll conductance (gm) under drought conditions. However, the physiological and structural contributions to the gm of leaves and their mechanisms in WDR under AWDI are still unclear. In this study, WDR (Hanyou 73) and drought‐sensitive rice (Huiliangyou 898) were selected as materials. Three irrigation patterns were established from transplanting to the heading stage, including conventional flooding irrigation (W1), moderate AWDI (W2), and severe AWDI (W3). A severe drought with a soil water potential of −50 kPa was applied for a week at the heading stage across all treatments and cultivars. The results revealed that severe drought reduced gas exchange parameters and gm but enhanced antioxidant enzyme activities and malondialdehyde content in the three treatments and both cultivars. The maximal photosynthetic rate (Amax) of HY73 in the W2 treatment was greater than that in the other combinations of cultivars and irrigation patterns. The contribution of leaf structure (54%) to gm (gm‐S, structural gm) was higher than that of leaf physiology (46%) to gm (gm‐P, physiological gm) in the W2 treatment of Hanyou 73. Additionally, gm‐S was significantly and linearly positively correlated with gm under severe drought. Moreover, both the initial and apparent quantum efficiencies were significantly and positively with gm in rice plants (p < 0.05). These results suggest that the improvements in photosynthesis and yield in the WDR combined with moderate AWDI can mainly be attributed to the enhancement of gm‐S under severe drought conditions. Quantum efficiency may be a potential factor in regulating photosynthesis by cooperating with the gm of rice plants under severe drought conditions. [ABSTRACT FROM AUTHOR]

Explanation of natural phenomena at one level of biological organisation almost always involves causes that are found at other levels. Although scientists thinking across levels find it easy to explain physiological phenomena, students often perceive this as a challenge. We developed a new graphic organiser called Zoom Map, which is a mode for structuring biological information along the levels of biological organisation and is designed to guide biology students when they need to consider the levels of organisation. The aim of this study is to examine how Zoom Map helps students explain a common phenomenon in plant physiology: leaves that are upright or wilted. Accordingly, we designed a teaching experiment covering 13 students. During the experiments, the students were videotaped. We used qualitative content analysis to examine the explanations. Our findings indicate that Zoom Map improved students' explanations of the phenomenon across multiple levels of organisation: The students used more levels than before, and they referred to lower levels that were lacking previously. Therefore, it can be concluded that students who use Zoom Map are supported in their ability to explain a biological phenomenon across the levels of biological organisation. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the impact of ethanol extracts from sea buckthorn and Cornelian cherry fruits and leaves on physiology of gastrointestinal tract cells. We used three cell lines relevant to the types of cells, which are exposed to bioactive compounds after oral administration, namely intestinal absorptive cells (Caco-2/HT-29 MTX model), hepatocytes (HepG2 cells) and immunocompetent cells (RAW 264.7 and P388D1 monocytes). The contents of antioxidant and bioactive polyphenols, such as cinnamic, caffeic and p-coumaric acids, rutin, myricetin, resveratrol, quercetin, apigenin and kaempferol, were assessed in the extracts using HPLC chromatography. The application of the extracts to Caco-2/HT-29-MTX cultures increased enterocyte differentiation markers (alkaline phosphatase and villin1 level) and goblet cell markers (mucins) over a fortnight. The extracts reduced lipid droplet size in hepatocytes challenged with hyperglycaemic glucose concentration, insulin and palmitate. Sea buckthorn leaf, fruit and Cornelian cherry leaf extracts blocked oxidative burst in the PMA-stimulated monocytes, while the sea buckthorn leaf and Cornelian cherry fruit extracts downregulated lipopolysaccharide-induced NO and IL-1β, respectively. The results indicate that the tested extracts modulate the behaviour of cells in the gastrointestinal tract in a beneficial way, especially regarding lipid accumulation and innate immunity actions. [ABSTRACT FROM AUTHOR]

Salt-sensitive trees in coastal wetlands are dying as forests transition to marsh and open water at a rapid pace. Forested wetlands are experiencing repeated saltwater exposure due to the frequency and severity of climatic events, sea-level rise, and human infrastructure expansion. Understanding the diverse responses of trees to saltwater exposure can help identify taxa that may provide early warning signals of salinity stress in forests at broader scales. To isolate the impacts of saltwater exposure on trees, we performed an experiment to investigate the leaf-level physiology of six tree species when exposed to oligohaline and mesohaline treatments. We found that species exposed to 3–6 parts per thousand (ppt) salinity had idiosyncratic responses of plant performance that were species-specific. Saltwater exposure impacted leaf photochemistry and caused early senescence in Acer rubrum, the most salt-sensitive species tested, but did not cause any impacts on plant water use in treatments with <6 ppt. Interestingly, leaf spectral reflectance was correlated with the operating efficiency of photosystem II (PSII) photochemistry in A. rubrum leaves before leaf physiological processes were impacted by salinity treatments. Our results suggest that the timing and frequency of saltwater intrusion events are likely to be more detrimental to wetland tree performance than salinity concentrations. [ABSTRACT FROM AUTHOR]

Fire-prone landscapes experience frequent fires, disrupting above-ground biomass and altering below-ground soil nutrient availability. Augmentation of leaf nutrients or leaf water balance can both reduce limitations to photosynthesis and facilitate post-fire recovery in plants. These modes of fire responses are often studied separately and hence are rarely compared. We hypothesized that under severe burning, woody plants of a coastal scrub ecosystem would have higher rates of photosynthesis (A net) than in unburned areas due to a transient release from leaf nutrient and water limitations, facilitating biomass recovery post-burn. To compare these fire recovery mechanisms in regrowing plants, we measured leaf gas exchange, leaf and soil N and P concentrations, and plant stomatal limitations in Australian native coastal scrub species across a burn sequence of sites at 1 year after severe fire, 7 years following a light controlled fire, and decades after any fire at North Head, Sydney, Australia. Recent burning stimulated increases in A net by 20% over unburned trees and across three tree species. These species showed increases in total leaf N and P as a result of burning of 28% and 50% for these macronutrients, respectively, across the three species. The boost in leaf nutrients and stimulated leaf biochemical capacity for photosynthesis, alongside species-specific stomatal conductance (g s) increases, together contributed to increased photosynthetic rates after burning compared with the long-unburned area. Photosynthetic stimulation after burning occurred due to increases in nutrient concentrations in leaves, particularly N, as well as stomatal opening for some species. The findings suggest that changes in species photosynthesis and growth with increased future fire intensity or frequency may be facilitated by changes in leaf physiology after burning. On this basis, species dominance during regrowth depends on nutrient and water availability during post-fire recovery. [ABSTRACT FROM AUTHOR]

Fruits play an important role in human life on our planet, since they supply a variety of essential services. One of the paramount crops in Pakistan is Citrus reticulata (Kinnow), which plays a vital role in the country's economy. The citrus crops are confronted with various challenges such as fungi, bacteria, nematodes, and viruses, all of which have adverse effects on the quality and yield of the fruits. Citrus canker, in particular, stands as the most fatal disease, affecting numerous citrus species worldwide, inflicting devastating consequences. The objective of this study was to evaluate the impact of citrus canker on the morphology, physiology of leaves, and the quality of citrus fruits. The research was conducted in four major citrus-producing tehsils of the Sargodha district. The study found significant differences in morphological and physiological traits between healthy fruits and those infected with citrus canker. Healthy fruits exhibited higher values in fruit weight (FW) of 149.02 g, peel thickness (PT) of 3.76 g, rag weight (RW) of 35.95 g, leaf area (LA) of 22.49 cm2, and juice weight compared to the citrus canker-infected fruits. The significant variations in fruit weight, juice weight, chlorophyll content, vitamin C content were present between healthy and diseased fruits and leaves. A biochemical study revealed that healthy fruits had greater levels of total soluble solids (TSS), TSS-acid ratio, vitamin C, and reducing power (RP), but citrus canker-infected fruits had a higher acidity percentage. The significant decreases in important morphological and physicochemical characteristics, emphasizing the necessity for immediate disease control techniques to safeguard the citrus sector and maintain food security. [ABSTRACT FROM AUTHOR]

Solar‐induced fluorescence (SIF) is a proxy of ecosystem photosynthesis that often scales linearly with gross primary productivity (GPP) at the canopy scale. However, the mechanistic relationship between GPP and SIF is still uncertain, especially at smaller temporal and spatial scales. We deployed a ultra‐hyperspectral imager over two grassland sites in California throughout a soil moisture dry down. The imager has high spatial resolution that limits mixed pixels, enabling differentiation between plants and leaves within one scene. We find that imager SIF correlates well with diurnal changes in leaf‐level physiology and gross primary productivity under well‐watered conditions. These relationships deteriorate throughout the dry down event. Our results demonstrate an advancement in SIF imaging with new possibilities in remotely sensing plant canopies from the leaf to the ecosystem. These data can be used to resolve outstanding questions regarding SIF's meaning and usefulness in terrestrial ecosystem monitoring. Plain Language Summary: Estimating the rate of carbon uptake by vegetation across space and time remains a challenge. Solar‐induced fluorescence (SIF), the emission of light by vegetation during photosynthesis, has recently emerged as a potential estimate of carbon uptake in many ecosystems and is observable from both satellites and ground‐based sensors. Here we present results from a field campaign with a novel SIF instrument that creates images (akin to a photo) across a landscape, allowing for SIF measurements from individual leaves, plants, or areas of interest. We find that SIF retrievals from the imager correspond to seasonal variations in carbon dioxide fixation rates and leaf‐level physiology relating to photosynthesis. We use this novel technology to improve understanding of SIF and carbon uptake across spatial and temporal scales. Key Points: Novel imagery technology enables solar‐induced fluorescence (SIF) acquisition across space and timeSIF diurnal and seasonal variations correspond to carbon fluxes and environmental conditionsImaging capacity predicts leaf‐level physiology across leaf, plant, and landscape scales [ABSTRACT FROM AUTHOR]

Summary: The temperature sensitivity (e.g. Q10) of night‐time leaf respiratory CO2 efflux (RCO2) is a fundamental aspect of leaf physiology. The Q10 typically exhibits a dependence on measurement temperature, and it is speculated that this is due to temperature‐dependent shifts in the relative control of leaf RCO2. Two decades ago, a review hypothesized that this mechanistically caused change in values of Q10 is predictable across plant taxa and biomes. Here, we discuss the most appropriate measuring protocol among existing data and for future data collection, to form the foundation of a future mechanistic understanding of Q10 of leaf RCO2 at different temperature ranges. We do this primarily via a review of existing literature on Q10 of night‐time RCO2 and only supplement this to a lesser degree with our own original data. Based on mechanistic considerations, we encourage that instantaneous Q10 of leaf RCO2 to represent night‐time should be measured: only at night‐time; only in response to short‐term narrow temperature variation (e.g. max. 10°C) to represent a given midpoint temperature at a time; in response to as many temperatures as possible within the chosen temperature range; and on still attached leaves. [ABSTRACT FROM AUTHOR]

Exploring the growth and physiological response mechanisms of rice under continuous drought stress circumstances can provide a significant scientific foundation and technological assistance for meeting drought difficulties, improving drought resistance and rice (Oryza sativa L.) output, and ensuring food security. In this study, a rice field experiment was conducted under a rain shelter with five different treatments set up: P1 (drought stress from tillering stage), P2 (drought stress from jointing–booting stage), P3 (drought stress from heading–flowering stage), P4 (drought stress from grain filling stage), and CK (adequate water management throughout the growth stage). Continuous drought stress from different growth stages with four levels (mild, medium, moderate, and severe). The results showed that the effects of different drought stress treatments on rice growth varied significantly. Compared with the CK treatment, plant height was reduced by 12.10%, 8.14%, 3.83%, and 1.06% in the P1, P2, P3, and P4 treatments, respectively, and the number of tillers was reduced by 23.83%, 18.91%, 13.47%, and 8.68%, respectively. With the increase in drought stress levels, SPAD values and Rubisco activity of rice leaf continued to decrease; SOD activity showed a decreasing trend, but the decreasing trend of POD and CAT activities was not significant, while MDA content showed an increasing trend. For yield components, continuous drought stress significantly reduced spike length of rice by an average of 3.5%, effective number of spikes by 18.9%, thousand grain weight by 3.7%, grain number per spike by 11.6%, and fruiting rate by 1.8%, respectively, compared to CK treatments during the growth period. In general, continuous drought stress during the early growth period affected the effective spike number and the grain number per spike. Continuous drought stress after the grain filling stage had the least effect on yield (17.62% of yield reduction), and water use efficiency (1.76 kg m−3) was much higher than other treatments. These researchers' findings provide insight into how rice physiology and growth react to continuous drought stress, which is significant for agricultural operations. [ABSTRACT FROM AUTHOR]

The current study aimed to quantify the effects of two drought intensities achieved by deprivation of watering for 45 and 65% of the volumetric soil moisture content (VSMC) for 14 days after wheat anthesis to identify physio-biochemical and molecular changes associated with drought tolerance in six genotypes with different drought tolerance. Drought at 65% of VSMC induced a significant decrease in the chlorophyll a content in the drought-sensitive genotype, which indicated a strong loss of photosynthetic reaction centres. Further, in the drought-tolerant genotype, the content of carotenoids, which could play a vital role in resisting water shortage stress, tended to increase. The increased production of malondialdehyde showed that the antioxidant system in the drought-sensitive genotypes was not properly activated. A significant decrease in catalase (CAT; EC 1.11.1.6) was observed at a 45% reduction in VSMC, compared to the control, in the drought-sensitive genotype, and at a reduction in VSMC of 65%, in all medium sensitive genotypes. Further, the drought-tolerant and -medium tolerant genotypes responded to drought with a decline in total glutathione concentrations with the intention to reinforce their defence system. Thereby, dehydroascorbate reductase (DHAR; EC 1.8.5.1), monodehydroascorbate reductase (MDHAR; EC 1.6.5.4), and glutathione reductase (GR; EC 1.6.4.2) were critical enzymes involved in the ascorbate–glutathione cycle together with CAT, showing their main role in the detoxification of ROS produced with the reduction in VSMC by 65%. The results of gene expression analysis showed that severe drought increased the levels of the DHN5 and WZY2 genes (that were significantly positively correlated) in the drought-tolerant genotype, whose grain weight, area, and length did not change in maturity. Also, it was seen that DHN5 expression showed a significant positive correlation with grain length and proline content at a 45% reduction in VSMC. The identification of different mechanisms under drought can contribute to the selection of drought-tolerant genotypes. [ABSTRACT FROM AUTHOR]

Biocontrol agents play a crucial role in agricultural production by reducing the use of pesticides and chemical fertilizers, controlling pests and diseases, and enhancing crop yield and quality. While extensive research has focused on the growth-promoting and yield-increasing effects of biocontrol agents on herbaceous plants, their impact on woody crops such as trees and shrubs has not been reported. This study investigates the effects of the actinomycete strain Act12, applied via root drenching and foliar spraying, on the flowering and fruit set rates, leaf physiology and enzyme activity, and fruit characteristics and yield of the jujube tree (Ziziphus jujuba Mill.). Additionally, this study analyzes the physicochemical properties of the soil and the diversity and community structure of its microorganisms. The results indicate that treatment with Act12 significantly altered the α and β diversity of soil microorganisms and enhanced the interaction networks among them. This led to increased levels of available nitrogen, phosphorus, and potassium in the soil, significantly improving nutrient availability. Consequently, there was an improvement in the number of flower buds and fruits, as well as an increase in the longitudinal diameter and individual fruit weight of the jujube. These effects significantly enhanced the yield and total sugar content of the winter jujube. Given these findings, Act12 can be considered an effective microbial agent for enhancing the yield and quality of winter jujube when applied to the soil. [ABSTRACT FROM AUTHOR]

Premise: While many studies have measured the aboveground responses of plants to mycorrhizal fungi at a single time point, little is known about how plants respond belowground or across time to mycorrhizal symbiosis. By measuring belowground responses and growth over time in many plant species, we create a more complete picture of how mycorrhizal fungi benefit their hosts. Methods: We grew 26 prairie plant species with and without mycorrhizal fungi and measured 14 functional traits to assess above‐ and belowground tissue quality and quantity responses and changes in resource allocation. We used function‐valued trait (FVT) modeling to characterize changes in species growth rate when colonized. Results: While aboveground biomass responses were positive, the response of traits belowground were much more variable. Changes in aboveground biomass accounted for 60.8% of the variation in mycorrhizal responses, supporting the use of aboveground biomass response as the primary response trait. Responses belowground were not associated with aboveground responses and accounted for 18.3% of the variation. Growth responses over time were highly variable across species. Interestingly, none of the measured responses were phylogenetically conserved. Conclusions: Mycorrhizal fungi increase plant growth in most scenarios, but the effects of these fungi belowground and across time are more complicated. This study highlights how differences in plant allocation priorities might affect how they utilize the benefits from mycorrhizal fungi. Identifying and characterizing these differences is a key step to understanding the effects of mycorrhizal mutualisms on whole plant physiology. [ABSTRACT FROM AUTHOR]

The genetic basis of plant response to light and heat stresses had been unveiled, and different molecular mechanisms of leaf cell homeostasis to keep high physiological performances were recognized in grapevine varieties. However, the ability to develop heat stress tolerance strategies must be further elucidated since the morpho-anatomical and physiological traits involved may vary with genotype × environment combination, stress intensity, and duration. A 3-year experiment was conducted on potted plants of Sardinian red grapevine cultivars Cannonau (syn. Grenache) and Carignano (syn. Carignan), exposed to prolonged heat stress inside a UV-blocking greenhouse, either submitted to low daily UV-B doses of 4.63 kJ m-2 d-2 (+UV) or to 0 kJ m-2 d-2 (-UV), and compared to a control (C) exposed to solar radiation (4.05 kJ m-2 d-2 average UV-B dose). Irrigation was supplied to avoid water stress, and canopy light and thermal microclimate were monitored continuously. Heat stress exceeded one-third of the duration inside the greenhouse and 6% in C. In vivo spectroscopy, including leaf reflectance and fluorescence, allowed for characterizing different patterns of leaf traits and metabolites involved in oxidative stress protection. Cannonau showed lower stomatal conductance under C (200 mmolm-2 s-2) but more than twice the values inside the greenhouse (400 to 900 mmol m-2 s-2), where water use efficiency was reduced similarly in both varieties. Under severe heat stress and -UV, Cannonau showed a sharper decrease in primary photochemical activity and higher leaf pigment reflectance indexes and leaf mass area. UV-B increased the leaf pigments, especially in Carignano, and different leaf cell regulatory traits to prevent oxidative damage were observed in leaf crosssections. Heat stress induced chloroplast swelling, plastoglobule diffusion, and the accumulation of secretion deposits in both varieties, aggravated in Cannonau -UV by cell vacuolation, membrane dilation, and diffused leaf blade spot swelling. Conversely, in Carignano UV-B, cell wall barriers and calcium oxalate crystals proliferated in mesophyll cells. These responses suggest an adaptive divergence among cultivars to prolonged heat stress and UV-B light. Further research on grapevine biodiversity, heat, and UV-B light interactions may give new insights on the extent of stress tolerance to improve viticulture adaptive strategies in climate change hotspots. [ABSTRACT FROM AUTHOR]

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It is unclear how high concentrations of copper affect the structure and function of roots in the process of controlling root entanglement in containers although copper pruning technology has been widely applied. One-year-old glossy privet (Ligustrum lucidum) seedlings were treated with latex carrier (T1), 100 g L− 1 Cu(OH)2 in combination with latex (T2), and a control (T0) without latex and Cu(OH)2. The roots were classified into seven classes according to diameter and six root orders by branching order. There were 6 root orders under the T2, one more than that under the T1 and T0. The length sum of the first to fourth root orders under the T2 was 52.4% and 132.0% higher than that under the T1 and T0. The T1 treatment significantly increased the length of the finest roots less than 0.50 mm in diameter, especially the roots less than 0.25 mm in diameter. No root circling was observed under the T2 treatment where the length of the tap root decreased and root volume increased. The T2 treatment significantly improved the plant height (+ 62.2% and + 24.1%), maximum net photosynthetic rate (+ 70.5% and + 63.8%), leaf area (+ 4.10% and + 37.6%), and total leaf number (+ 143.0% and + 66.9%) compared to the T0 and the T1. Latex treatment enhanced the growth of the lateral roots by increasing humidity and temperature in the containers but could not control root circling, whose improvement mechanism was different from that of copper. [ABSTRACT FROM AUTHOR]

Summary: Turgor loss point (TLP) is an important proxy for plant drought tolerance, species habitat suitability, and drought‐induced plant mortality risk. Thus, TLP serves as a critical tool for evaluating climate change impacts on plants, making it imperative to develop high‐throughput and in situ methods to measure TLP.We developed hyperspectral pressure–volume curves (PV curves) to estimate TLP using leaf spectral reflectance. We used partial least square regression models to estimate water potential (Ψ) and relative water content (RWC) for two species, Frangula caroliniana and Magnolia grandiflora. RWC and Ψ's model for each species had R2 ≥ 0.7 and %RMSE = 7–10. We constructed PV curves with model estimates and compared the accuracy of directly measured and spectra‐predicted TLP.Our findings indicate that leaf spectral measurements are an alternative method for estimating TLP. F. caroliniana TLP's values were −1.62 ± 0.15 (means ± SD) and −1.62 ± 0.34 MPa for observed and reflectance predicted, respectively (P > 0.05), while M. grandiflora were −1.78 ± 0.34 and −1.66 ± 0.41 MPa (P > 0.05).The estimation of TLP through leaf reflectance‐based PV curves opens a broad range of possibilities for future research aimed at understanding and monitoring plant water relations on a large scale with spectral ecophysiology. [ABSTRACT FROM AUTHOR]

Background: Drought is a critical limiting factor affecting the growth and development of spring maize (Zea mays L.) seedlings in northeastern China. Sodium 5-nitroguaiacol (5-NGS) has been found to enhance plant cell metabolism and promote seedling growth, which may increase drought tolerance. Methods: In the present study, we investigated the response of maize seedlings to foliar application of a 5-NGS solution under osmotic stress induced by polyethylene glycol (PEG-6000). Four treatment groups were established: foliar application of distilled water (CK), foliar application of 5-NGS (NS), osmotic stress + foliar application of distilled water (D), and osmotic stress + foliar application of 5-NGS (DN). Plant characteristics including growth and photosynthetic and antioxidant capacities under the four treatments were evaluated. Results: The results showed that under osmotic stress, the growth of maize seedlings was inhibited, and both the photosynthetic and antioxidant capacities were weakened. Additionally, there were significant increases in the proline and soluble sugar contents and a decrease in seedling relative water content (RWC). However, applying 5-NGS alleviated the impact of osmotic stress on maize seedling growth parameters, particularly the belowground biomass, with a dry mass change of less than 5% and increased relative water content (RWC). Moreover, treatment with 5-NGS mitigated the inhibition of photosynthesis caused by osmotic stress by restoring the net photosynthetic rate (Pn) through an increase in chlorophyll content, photosynthetic electron transport, and intercellular CO2 concentration (Ci). Furthermore, the activity of antioxidant enzymes in the aboveground parts recovered, resulting in an approximately 25% decrease in both malondialdehyde (MDA) and H2O2. Remarkably, the activity of enzymes in the underground parts exhibited more significant changes, with the contents of MDA and H2O2 decreasing by more than 50%. Finally, 5-NGS stimulated the dual roles of soluble sugars as osmoprotectants and energy sources for metabolism under osmotic stress, and the proline content increased by more than 30%. We found that 5-NGS played a role in the accumulation of photosynthates and the effective distribution of resources in maize seedlings. Conclusions: Based on these results, we determined that foliar application of 5-NGS may improve osmotic stress tolerance in maize seedlings. This study serves as a valuable reference for increasing maize yield under drought conditions. [ABSTRACT FROM AUTHOR]

Understanding the light adaptation of plants is critical for conservation. Platycrater arguta, an endangered deciduous shrub endemic to East Asia, possesses high ornamental and phylogeographic value. However, the weak environmental adaptability of P. arguta species has limited its general growth and conservation. To obtain a deeper understanding of the P. arguta growth conditions, we examined the leaf morphology and physiology via anatomical and chloroplast ultrastructural analyses following exposure to different natural light intensities (full light, 40%, and 10%). The findings indicated that P. arguta seedings in the 10% light intensity had significantly improved leaf morphological characteristics and specific leaf area compared to those exposed to other intensities. The net photosynthetic rate, chlorophyll (Chl) content, photosynthetic nitrogen use efficiency (PNUE), and photosynthetic phosphorus use efficiency (PPUE) exhibited marked increases at a 10% light intensity compared to both 40% light and full light intensities, whereas the light compensation point and dark respiration levels reached their lowest values under the 10% light condition. With reduced light, leaf thickness, palisade tissue, spongy tissue, and stomatal density significantly decreased, whereas the stomatal length, stomatal width, and stomatal aperture were significantly elevated. When exposed to 10% light intensity, the ultrastructure of chloroplasts was well developed, chloroplasts and starch grain size, the number of grana, and thylakoids all increased significantly, while the number of plastoglobules was significantly reduced. Relative distance phenotypic plasticity index analysis exhibited that P. arguta adapts to varying light environments predominantly by adjusting PPUE, Chl b, PNUE, chloroplast area, and the activity of PSII reaction centers. We proposed that P. arguta efficiently utilizes low light to reconfigure its energy metabolism by regulating its leaf structure, photosynthetic capacity, nutrient use efficiency, and chloroplast development. [ABSTRACT FROM AUTHOR]

Elevated atmospheric CO2 concentration (e[CO2]) and varied nitrogen (N) fertilization levels may mediate the different responses of C4 crops to progressive soil drought. In this study, the effects of reduced N (N1, 0.8 g pot−1) and adequate N (N2, 1.6 g pot−1) supply on leaf physiology, plant growth and water use efficiency (WUE) of maize (C4 crop) exposed to progressive soil drought grown at ambient CO2 (a[CO2], 400 ppm) and elevated CO2 (e[CO2], 800 ppm) concentration were investigated. The results indicated that compared with a[CO2], net photosynthetic rate (An) and leaf water potential (Ψl) at e[CO2] were maintained in maize leaves, while stomatal conductance (gs), transpiration rate and leaf hydraulic conductance were decreased, leading to enhanced WUE from stomatal to leaf scale. Despite An and Ψl of e[CO2] plants were more sensitive to progressive soil drought under both N fertilization levels, e[CO2] would increase leaf ABA concentration ([ABA]leaf) but decline the gs response to [ABA]leaf under N1 supply. e[CO2] coupled with N1 fertilization was conducive to enlarging leaf area, promoting specific leaf area, root and total dry mass, whereas reduced stomatal aperture and plant water use under progressive drought stress, contributing to an improvement in plant WUE, implying a better modulation of maize leaf stomata and water status under reduced N supply combined with e[CO2] responding to progressive soil drought. These findings in the current study would provide valuable advice for N management on maize (C4) crop efficient water use in a drier and CO2‐enriched environment. [ABSTRACT FROM AUTHOR]

Copper (Cu), as an essential microelement for plant growth, may have impacts on root activity and function under excessive conditions, thereby affecting the physiology and growth of plants. One-year-old golden dewdrop (Duranta erecta) cuttings were treated with six Cu2+ levels of 0.2, 2.0, 20.0, 200.0, and 2000.0 mmol L-1 for 7, 21, and 35 days by hydroponic culture with 0.0 mmol L-1 as the control. The obvious negative effects of 200.0 and 2000.0 mmol L-1 Cu2+ on the aboveground and belowground parts of D. erecta were observed after 35 days of treatment. The root activity at 20.0, 200.0, and 2000.0 mmol L-1 Cu2+ was 16%, 21%, and 22% lower than the control, while no significant difference between 2.0 mmol L-1 Cu2+ and the control. The net photosynthetic rate and transpiration rate showed a decreasing trend with treatment time when Cu2+ concentration was higher than 20.0 mmol L-1. The chlorophyll contents, leaf circumference, and leaf area at 2.0 mmol L-1 Cu2+ were significantly higher than the control and other Cu2+ treatments. The Cu concentration of roots, stems, and leaves at 2000.0 mmol L-1 Cu2+ was 22.9, 3.3, and 2.7 times higher than the control. Our results indicate that 2000.0 mmol L-1 Cu2+ destroyed the root function, causing excessive Cu accumulation in the roots, stems and leaves, consequently decreasing plant physiology and growth. Based on the short-term results, 2.0 mmol L-1 Cu2+ was the suitable concentration for D. erecta in hydroponic culture. [ABSTRACT FROM AUTHOR]

The effect of drought stress on leaf physiology was studied in 10-month-old plants of Sindora siamensis. Plants were either placed in an open greenhouse (unhardening; UH) or in an open field (open field hardening; H) for 45 days. Both the UH and H plants stopped receiving water (D) until the initial drought injury and then rewatered (R) until complete recovery. Results showed necrosis in the leaves of UH + D, while H + D showed wilting at Day 7 after drought. A greater degree of necrosis was found in UH + D + R but made complete recovery in H + D + R at Day 4 after rewatering. Drought stress resulted in decreased leaf area in H, and reduced leaf and stem water status, PSII efficiency, net photosynthetic rate, stomatal conductance and transpiration rate in both UH and H. It also resulted in an increase in water use efficiency in both UH and H. Electrolyte leakage and malondialdehyde contents in UH were markedly increased due to drought stress. These results suggest that unhardened young plants of Sindora exposed to drought exhibited enhanced stomata behaviour by minimising open stomata and transpiration, resulting in high efficiency of water usage. However, there was still membrane damage from lipid peroxidation, which caused necrosis. Open field hardened plants exposed to drought demonstrated reduced open stomata and transpiration, thereby preserving leaf and soil water status and enhancing water use efficiency. This may be a reduction in lipid peroxidation though an oxidative scavenging mechanism that causes a slight alteration in membrane stability and a slight necrosis. [ABSTRACT FROM AUTHOR]

Abiotic stress caused by soil salinization remains a major global challenge that threatens and severely impacts crop growth, causing yield reduction worldwide. In this study, we aim to investigate the damage of salt stress on the leaf physiology of two varieties of rice (Huanghuazhan, HHZ, and Xiangliangyou900, XLY900) and the regulatory mechanism of Hemin to maintain seedling growth under the imposed stress. Rice leaves were sprayed with 5.0 mmol•L-1 Hemin or 25.0 mmol•L-1 ZnPP (Zinc protoporphyrin IX) at the three leaf and one heart stage, followed by an imposed salt stress treatment regime (50.0 mmol•L-1 sodium chloride (NaCl)). The findings revealed that NaCl stress increased antioxidant enzymes activities and decreased the content of nonenzymatic antioxidants such as ascorbate (AsA) and glutathione (GSH). Furthermore, the content of osmoregulatory substances like soluble proteins and proline was raised. Moreover, salt stress increased reactive oxygen species (ROS) content in the leaves of the two varieties. However, spraying with Hemin increased the activities of antioxidants such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) and accelerated AsA-GSH cycling to remove excess ROS. In summary, Hemin reduced the effect of salt stress on the physiological characteristics of rice leaves due to improved antioxidant defense mechanisms that impeded lipid peroxidation. Thus, Hemin was demonstrated to lessen the damage caused by salt stress. [ABSTRACT FROM AUTHOR]

Mixed cultivation with legumes may alleviate the nitrogen (N) limitation of monoculture Eucalyptus. However, how leaf functional traits respond to N in mixed cultivation with legumes and how they affect tree growth are unclear. Thus, this study investigated the response of leaf functional traits of Eucalyptus urophylla × Eucalyptus grandis (E. urophylla × E. grandis) and Dalbergia odorifera (D. odorifera) to mixed culture and N application, as well as the regulatory pathways of key traits on seedling growth. In this study, a pot-controlled experiment was set up, and seedling growth indicators, leaf physiology, morphological parameters, and N content were collected and analyzed after 180 days of N application treatment. The results indicated that mixed culture improved the N absorption and photosynthetic rate of E. urophylla × E. grandis, further promoting seedling growth but inhibiting the photosynthetic process of D. odorifera, reducing its growth and biomass. Redundancy analysis and path analysis revealed that leaf nitrogen content, pigment content, and photosynthesis-related physiological indicators were the traits most directly related to seedling growth and biomass accumulation, with the net photosynthetic rate explaining 50.9% and 55.8% of the variation in growth indicators for E. urophylla × E. grandis and D. odorifera, respectively. Additionally, leaf morphological traits are related to the trade-off strategy exhibited by E. urophylla × E. grandis and D. odorifera based on N competition. This study demonstrated that physiological traits related to photosynthesis are reliable predictors of N nutrition and tree growth in mixed stands, while leaf morphological traits reflect the resource trade-off strategies of different tree species. [ABSTRACT FROM AUTHOR]

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The extreme drought events in the last years caused high mortality amongst European beech (Fagus sylvatica L.) across Central Europe. Thus, knowledge of the response of beech to drought and its ability to recover its xylem and leaf functions after drought release is needed to better understand beech survival. In this study, changes in xylem function, leaf gas exchange, chlorophyll fluorescence and morphology of European beech saplings during drought and recovery phases were assessed. Beech saplings were exposed to three different watering intensities—well-watered (W), moderately drought stressed (M) and severely drought stressed (S) for 25 days, and then saplings were rewatered for 14 days. Reduced irrigation caused a drop in shoot water potential to −1.1 and −3.1 MPa in M and S saplings, respectively. Stomatal conductance in M and S saplings decreased to 15 and 5 per cent of that in W saplings, respectively, and it corresponded with a decrease in the photosynthesis rate and chlorophyll fluorescence parameters. Leaf water content and shoot functional xylem area were significantly affected by drought only in S saplings. Hence, these parameters could be used as sensitive indicators that distinguish plants at no risk of mortality from those at increasing risk under drought stress. In S saplings, some leaves also dried from the edges, leaving a green active central part. During the recovery phase, the leaf gas exchange and chlorophyll fluorescence parameters had recovered 4 days after rewatering in M saplings, whereas in S saplings, they were still lower after 2 weeks. Moreover, xylem function did not fully recover in S saplings till the end of the recovery phase. Hence, subsequent drought periods, even of lower intensity, could lead to tree mortality if tree functions have not fully recovered from the previous drought. [ABSTRACT FROM AUTHOR]

One of the well-documented effects of regional warming in Antarctica is the impact on flora. Warmer conditions modify several leaf anatomical traits of Antarctic vascular plants, increasing photosynthesis and growth. Given that CO2 and water vapor partially share their diffusion pathways through the leaf, changes in leaf anatomy could also affect the hydraulic traits of Antarctic plants. We evaluated the effects of growth temperature on several anatomical and hydraulic parameters of Antarctic plants and assessed the trait co-variation between these parameters and photosynthetic performance. Warmer conditions promoted an increase in leaf and whole plant hydraulic conductivity, correlating with adjustments in carbon assimilation. These adjustments were consistent with changes in leaf vasculature, where Antarctic species displayed different strategies. At higher temperature, Colobanthus quitensis decreased the number of leaf xylem vessels, but increased their diameter. In contrast, in Deschampsia antarctica the diameter did not change, but the number of vessels increased. Despite this contrasting behavior, some traits such as a small leaf diameter of vessels and a high cell wall rigidity were maintained in both species, suggesting a water-conservation response associated with the ability of Antarctic plants to cope with harsh environments. [ABSTRACT FROM AUTHOR]

Rational fertilization is the main measure to improve crop yield, but there are differences in the optimal effects of nitrogen (N), phosphorus (P) and potassium (K) rationing exhibited by the same crop species in different regions and soil conditions. In order to determine the optimum fertilization ratio for high yield of Sapindus mukorossi in western Fujian to provide scientific basis. We carried out the experimental design with different ratios of N, P and K to investigate the effects of fertilization on the yield. and leaf physiology of Sapindus mukorossiand soil properties. Results showed that the yield of Sapindus mukorossi reached the highest value (1464.58 kg ha-1) at N2P2K2 treatment, which increased to 1056.25 kg ha-1 compared with the control. There were significant differences in the responses of soil properties and leaf physiological factors to fertilization treatments. Factor analysis showed that the integrated scores of soil factors and leaf physiological characteristic factors of Sapindus mukorossi under N2P2K2 fertilization treatment were the highest, which effectively improved the soil fertility and leaf physiological traits. The yield of Sapindus mukorossi showed a highly significant linear positive correlation with the integrated scores (r=0.70, p<0.01). Passage analysis showed that soil available nitrogen content, organic carbon content, and leaf area index were the key main factors to affect the yield. RDA showed that soil organic carbon and available phosphorus were the most important factors to affect leaf physiological traits. We recommend that the optimum fertilization ratio of Sapindus mukorossi was 0.96Kg N, 0.80Kg P and 0.64Kg K per plant. Reasonable fertilization can improve soil fertility and leaf physiological traits, while excessive fertilization has negative effects on soil fertility, leaf physiology and yield. This study provides theoretical support for scientific cultivation of woody oil seed species. [ABSTRACT FROM AUTHOR]

Secondary sexual dimorphism (SSD) in flowering plants is expressed by sexual differences of characters that are not directly related to gamete production. The leaf C/N ratio, photosynthetic traits or clonal responses have never been studied in relation to SSD in yerba‐mate. It was hypothesized that leaf and plant photosynthesis are higher in female than in male individuals because females must supply photoassimilates to compensate for the additional reproductive investments of SSD in biomass. Here, we investigated how two contrasting light environments (monoculture—MO and agroforestry—AFS) and plant genders change leaf and plant photosynthesis, plant architecture, leaf and branch biomass production and C and N investments of two male and two female clones. To model the 3D yerba‐mate structure, virtual trees were constructed using measurements of plant morphology using VPlant modelling software. The light‐response curves of leaf CO2 assimilation were used to model instantaneous leaf and daily plant photosynthesis. Photosynthetic traits derived from light‐response curves did not differ between MO and AFS. Some architectural traits were segregated sexually only in MO, while some physiological ones only in AFS. Leaf photosynthesis was higher in females than in males in AFS over a large part of the diurnal cycle, but SSD was not expressed in carbon gains at plant or daily scales. Leaf C/N ratio was higher in MO than in AFS, indicating MO as an ecosystem with higher degree of environmental degradation. Female clones had leaves with lower C/N ratio than males in both systems, relating to higher leaf photosynthesis on an area basis in females. SSD expressed in leaf photosynthesis over a large part of the diurnal cycle in AFS was not observed in carbon gains at plant or daily scales, indicating that the integration of physiology and architecture equalized the gender specificities. The insensitivity of photosynthetic traits derived from light‐response curves indicated acclimation of yerba‐mate leaves to a wide range of incoming light. [ABSTRACT FROM AUTHOR]

Lead (Pb) can be found in metallic, organic, or inorganic forms, having no function in plant metabolism. This work aimed to evaluate the performance of Peltophorum dubium (Spreng.) Taub., an arboreal legume native to South America, in soils contaminated with Pb, based on the analysis of morphophysiological modifications in its leaves and roots, its tolerance index, and its vegetative growth. The experiment was conducted under a completely randomized design, in a greenhouse, using four treatments, namely the control (without lead) and three lead concentrations (100, 300, and 500 mg/kg soil−1), each treatment consisting of five replicates. The fresh and dry weight of leaves, stem, and root and the Tolerance Index for Pb were measured at the end of the experiment. Concerning the leaf anatomy, the thickness of the adaxial epidermis, abaxial epidermis, the palisade and spongy parenchyma, and the total thickness of the leaflets were analyzed. The cross-section vessel element area was evaluated in the root. Nitrate, soluble proteins, and ureides were evaluated in leaves and roots. There was an increase in the thickness of the abaxial epidermis, in the palisade and spongy parenchyma, and the total thickness of the leaflets, and a decrease in the root cross-section vessel element area. The leaves showed an increase in the concentrations of soluble compounds, while the roots showed a decrease in the concentration of these compounds. The species presents a tolerance index superior to 0.7 for all treatments, having survived even at the concentration of 500 mg Pb dm−3. [ABSTRACT FROM AUTHOR]

Salt-sensitive trees in coastal wetlands are dying as forests transition to marsh and open water at a rapid pace. Forested wetlands are experiencing repeated saltwater exposure due to the frequency and severity of climatic events, sea-level rise, and human infrastructure expansion. Understanding the diverse responses of trees to saltwater exposure can help identify taxa that may provide early warning signals of salinity stress in forests at broader scales. To isolate the impacts of saltwater exposure on trees, we performed an experiment to investigate the leaf-level physiology of six tree species when exposed to oligohaline and mesohaline treatments. We found that species exposed to 3–6 parts per thousand (ppt) salinity had idiosyncratic responses of plant performance that were species-specific. Saltwater exposure impacted leaf photochemistry and caused early senescence in Acer rubrum, the most salt-sensitive species tested, but did not cause any impacts on plant water use in treatments with A. rubrum leaves before leaf physiological processes were impacted by salinity treatments. Our results suggest that the timing and frequency of saltwater intrusion events are likely to be more detrimental to wetland tree performance than salinity concentrations.

Background and aims: Water is fundamental to the growth of plants by participating in plant metabolism, and nutrient transport and maintaining the integrity of the hydraulic system. Knowledge of water use characteristics among co-occurring plant species is crucial for understanding the ecohydrological processes and community assemblages. However, interspecific interactions with respect to water sources and physiological activity remain poorly understood. Methods: The stable oxygen isotope values of xylem and soil water, and leaf physiological characteristics were measured in three communities in the Mu Us Desert, northwest China: a mixed shrub and grasses community; a pure shrub community; and a pure grasses community. Results: In mixed communities, the main water source for shrubs shifted to deeper soil layers than in pure communities, whereas grass water use switched to shallower soil layers. Leaf photosynthetic rates, stomatal conductance, transpiration, and water potential of both species were significantly lower in mixed communities than in pure communities. These results suggest that interspecific interactions influenced plant water use patterns. The water-use efficiency of shrubs increased in mixed communities, whereas that of grasses decreased, indicating that grasses exacerbated water stress on shrubs, while shrubs relieved water stress on grasses. Additionally, leaf physiological activity was positively correlated with shallower water sources and negatively correlated with deeper water sources. Conclusion: Our findings show that plants responded to interspecific interactions under drought conditions through the coupling of plant water sources with leaf physiologies. The present study provides important insights into water-related reforestation and ecological management in dryland ecosystems. [ABSTRACT FROM AUTHOR]

Frequent fungicide applications are required to manage grapevine powdery mildew (Erysiphe necator). However, this practice is costly and has led to widespread fungicide resistance. A method of monitoring in-field fungicide efficacy could help growers maximize spray-interval length, thereby reducing costs and the rate of fungicide resistance emergence. The goal of this study was to evaluate if hyperspectral sensing in the visible to shortwave infrared range (400 to 2,400 nm) can quantify foliar fungicide efficacy on grape leaves. Commercial formulations of metrafenone, Bacillus mycoides isolate J (BmJ), and sulfur were applied on Chardonnay grapevines in vineyard or greenhouse settings. Foliar reflectance was measured with handheld hyperspectral spectroradiometers at multiple days post-application. Fungicide efficacy was estimated as a proxy for fungicide residue and disease control measured with the Blackbird microscopy imaging robot. Treatments could be differentiated from the untreated control with an accuracy of 73.06% for metrafenone, 67.76% for BmJ, and 94.10% for sulfur. The change in spectral reflectance was moderately correlated with the cube root of the area under the disease progress curve for metrafenone- and sulfur-treated samples (R2 = 0.38 and 0.36, respectively) and with sulfur residue (R2 = 0.42). BmJ treatment impacted foliar physiology by enhancing the leaf mass/area and reducing the nitrogen and total phenolic content as estimated from spectral reflectance. The results suggest that hyperspectral sensing can be used to monitor in-situ fungicide efficacy, and the prediction accuracy depends on the fungicide and the time point measured. The ability to monitor in-situ fungicide efficacy could facilitate more strategic fungicide applications and promote sustainable grapevine protection. [ABSTRACT FROM AUTHOR]

Drought stress is increasing in frequency and severity with the progression of global climate change, thereby becoming a major concern for the growth and yield of crop plants, including wheat. The current challenge is to explore different ways of developing wheat genotypes with increased tolerance to drought. Therefore, we renewed interest in 'ancient' varieties expected to be more tolerant to environmental stress than the few elite varieties nowadays cultivated. This study aimed to perform comparative analysis of the effect of drought-simulating polyethylene glycol (PEG-6000) treatment on morpho-anatomical and physiological foliar traits of two durum wheat seedlings cultivars, Saragolla and Svevo, as these can reflect the adaptability of the plant to the environment to a certain extent. Results demonstrated that drought-stressed Saragolla leaves exhibited a greater reduction of stomatal density, a minor reduction of stomatal pore width, a wider xylem vessel mean area, greater compactness of mesophyll cells, a minor loss of chlorophyll content, as well as better photosynthetic and growth performance compared to the other variety. From such behaviours, we consider the Saragolla cultivar more drought tolerant than Svevo and therefore probably very promising for cultivation in dry areas. [ABSTRACT FROM AUTHOR]

Trees' responses to mistletoes occur at multiple organization levels (e.g., leaf, individual, population), yet integrating these multi‐scale responses is still challenging. Here, we compared the traits of infected versus uninfected trees over multiple scales, from leaf anatomy and physiology to canopy allometries and individual growth rate and survivorship. We tested the hypotheses that mistletoes lead in the host (1) the production of leaves with a conservative resource‐use strategy, (2) more mechanically stable canopies and (3) reductions in growth and survival probability in the trees they infect. We addressed these hypotheses in the widespread savanna tree Vochysia thyrsoidea and xylem‐tapping mistletoe Psittacanthus robustus in the Brazilian Cerrado, a global biodiversity hotspot. We found that (1) mistletoe infection did not affect key traits associated with resource conservativeness, such as leaf mass per area (LMA) and carbon assimilation rates (A). Likewise, (2) hosts did not increase the mechanical safety of their trunks in response to mistletoe infection since infected and uninfected trees had a similar allometric scaling between height and crown volume against stem diameter. (3) At the population level, both the relative growth rate and survival probability decreased as the number of parasites increased. However, zero growth and a 50% chance of mortality were estimated to occur in a minority of heavily infected trees (>7 and 14 parasites, respectively). Our results challenge the idea that mistletoes have a ubiquitous negative impact on their hosts. We highlight, therefore, the need for clarifying the mechanisms that allow trees to maintain their functioning even in the face of mistletoe parasitism. [ABSTRACT FROM AUTHOR]

Background: Essential micronutrient Boron (B) plays crucial roles in plant survival and reproduction but becomes toxic in higher quantities. Although plant cells have different B transport systems, B homeostasis is mainly maintained by two transporter protein families: B exporters (BOR) and nodulin-26-like intrinsic proteins (NIP). Their diversity and differential expression are responsible for varied B tolerance among plant varieties and species. Longan is a highly admired subtropical fruit with a rising market in China and beyond. In the present study, we cultured Shixia (SX) and Yiduo (YD), two differently characterized Longan cultivars, with foliar B spray. We analyzed their leaf physiology, fruit setting, B content, and boron transporter gene expression of various tissue samples. We also traced some of these genes' subcellular localization and overexpression effects. Results: YD and SX foliage share similar microstructures, except the mesophyll cell wall thickness is double in YD. The B spray differently influenced their cellular constituents and growth regulators. Gene expression analysis showed reduced BOR genes expression and NIP genes differential spatiotemporal expression. Using green fluorescent protein, two high-expressing NIPs, NIP1 and NIP19, were found to translocate in the transformed tobacco leaves' cell membrane. NIPs transformation of SX pollen was confirmed using magnetic beads and quantified using a fluorescence microscope and polymerase chain reaction. An increased seed-setting rate was observed when YD was pollinated using these pollens. Between the DlNIP1 and DlNIP19 transformed SX pollen, the former germinated better with increasing B concentrations and, compared to naturally pollinated plants, had a better seed-setting rate in YD♀ × SX♂. Conclusion: SX and YD Longan have different cell wall structures and react differently to foliar B spray, indicating distinct B tolerance and management. Two B transporter NIP genes were traced to localize in the plasma membrane. However, under high B concentrations, their differential expression resulted in differences in Jasmonic acid content, leading to differences in germination rate. Pollination of YD using these NIPs transformed SX pollen also showed NIP1 overexpression might overcome the unilateral cross incompatibility between YD♀ × SX♂ and can be used to increase Longan production. [ABSTRACT FROM AUTHOR]

Solar energy absorbed by plants can be redistributed between photosystems in the process termed "state transitions" (ST). ST represents a reversible transition of a part of the PSII light harvesting complex (L-LHCII) between photosystem II (PSII) and photosystem I (PSI) in response to the change in light spectral composition. The present work demonstrates a slower development of the state 1 to state 2 transition, i.e., L-LHCII transition from PSII to PSI, in the leaves of dicotyledonous arabidopsis (Arabidopsis thaliana) than in the leaves of monocotyledonous barley (Hordeum vulgare) plants that was assessed by the measurement of chlorophyll a fluorescence at 77 K and of chlorophyll a fluorescence at room temperature. It is known that the first step of the state 1 to state 2 transition is phosphorylation of Lhcb1 and Lhcb2 proteins; however, we detected no difference in the rate of accumulation of these phosphorylated proteins in the studied plants. Therefore, the parameters, which possibly affect the second step of this transition, i.e., the migration of L-LHCII complexes along the thylakoid membrane, were evaluated. Spin-probe EPR measurements demonstrated that the thylakoid membranes viscosity in arabidopsis was higher compared to that in barley. Moreover, confocal microscopy data evidenced the different size of chloroplasts in the leaves of the studied species being larger in arabidopsis. The obtained results suggest that the observed deference in the development of the state 1 to state 2 transition in arabidopsis and barley is caused by the slower L-LHCII migration rate in arabidopsis than in barley plants rather than by the difference in the Lhcb1 and Lhcb2 phosphorylation. [ABSTRACT FROM AUTHOR]

Potato is an important crop worldwide and threatened by various environmental stresses, including elevated ozone (e[O3]). Here, we conducted a meta-analysis to quantify the effect of e[O3] on potato plants and how it varies depending upon different experimental conditions. Regarding plant growth and biomass, e[O3] significantly decreased shoot biomass by 18% and belowground biomass by 35%, while it increased the leaf area index by 19% and total number of injured leaves by 146%. As for yield, e[O3] significantly decreased the total tuber number by 21%. A relatively pronounced effect of e[O3] on the stomatal conductance was observed when exposure lasted 31–60 days, which was significantly greater than that after exposure lasted 96–311 days. The overall quantity of leaves was mainly decreased by higher (100–150 ppb) than lower (30–80 ppb) concentrations of e[O3] compared to ambient O3. The effect of e[O3] on the total tuber number was significant mainly when exposure lasted 31–90 days and was greater in plants grown in growth chambers than those planted in open-top chambers and glasshouses. The effect of e[O3] stress on physiology, growth, and yield varied among cultivars, with some cultivars showing marked tolerance relative to other cultivars. The findings can guide strategies to manage the negative impacts of e[O3] stress on potato production. [ABSTRACT FROM AUTHOR]

The formation and functioning of the photosynthetic apparatus (PSA) is under the general control of the plant organism and constantly changing environmental conditions. The authors studied age-related and adaptive changes in the pigment complex, spectral properties, and the state of photosystem II (PSII) leaves of partial shoots of a summer-winter-green herbaceous perennial Ajuga reptans L. (bugle) in connection with overwintering. Rosette leaves of a new generation appearing in May–June quickly accumulated photosynthetic pigments and formed PSA with a maximal quantum efficiency of PSII (Fv/Fm) and actual quantum yield of PSII (ФPSII). In autumn (September–October), the content of chlorophylls was 10 mg/g dry weight, the value of Fv/Fm was 0.8 rel. units, and the level of ФPSII at PAR 130 µmol quanta/(m2 s) was approximately 0.7 rel. units. Overwintered leaves contained half as much photosynthetic pigments, accumulated a significant amount of anthocyanins, and were characterized by low photochemical activity and a high level of de-epoxidation of pigments of the violaxanthin cycle. With the resumption of active vegetation of plants (May), a partial restoration of the pigment pool and the repair of PSA of overwintered leaves were noted, as evidenced by an increase in the quantum yield PSII. The completion of the leaf life cycle was accompanied by a decrease in ФPSII up to 0.5 rel. units and a sharp increase in the thermal dissipation of absorbed excitation energy (NPQ) to 0.9 rel. units. Seasonal changes of spectral properties of leaves and photochemical reflectance indices generally corresponded to the dynamics content pigments and the efficiency of the use of light in photosynthesis. The results obtained indicate a significant transformation of the structural and functional organization of PSA in the ontogeny of overwintering leaves. The genetically fixed property of winter green plants to preserve leaves is based on the ability of their PSA to restore functional activity after the shock impact of overwintering, which is facilitated by a complex of adaptive and protective mechanisms. [ABSTRACT FROM AUTHOR]

• Mistletoes are keystone species in resource-poor environments. • Viscum rotundifolium parasitizes the evergreen tree Boscia albitrunca in arid savannas. • We measured photosynthesis, chlorophyll contents and water potential of B. albitrunca and V. rotundifolium. • Non-host B. albitrunca trees attained greater photosynthetic, chlorophyll contents and water potential rates than host trees and the mistletoe. • Host trees suffer reduced access to water and lower carbon gain due to mistletoe infection. Mistletoes can have detrimental effects on host trees. Mistletoe-infected trees may suffer from reduced growth and loss of vigor thereby contributing to low productivity of host trees. However, hosts may tolerate low levels of infection. This study aimed to determine photosynthetic rate, chlorophyll content and transpiration rate of a mistletoe-host pair (Viscum rotundifolium - Boscia albitrunca) and the water potential of two mistletoe host pairs (V. rotundifolium - B. albitrunca and Tapinanthus oleifolius-Senegalia mellifera) in a semi-arid savanna at Windhoek, Namibia. Photosynthetic rates were measured using a LI-6400XT photosynthesis system, while photosynthetic pigments were extracted in acetone and quantified spectrophotometrically. Plant water potential was measured using a Scholander pressure chamber. Results revealed greater photosynthetic rates and amounts of photosynthetic pigments in B. albitrunca than in V. rotundifolium while transpiration rates showed opposite trends to photosynthetic rates. Non-host B. albitrunca trees recorded significantly higher photosynthetic rates than the hosts, which suggests a parasite-induced reduction of photosynthetic rate in host plants. Water potential was greater in host trees than in mistletoes. These findings show negative effects of mistletoes on host trees, which may ultimately affect their reproduction and survival. Further research may be required to determine effects of parasite density on host trees. [ABSTRACT FROM AUTHOR]

One of the most fundamental aspects of a species' behavioral strategy is its activity budget; for primates this generally involves the allocation of available time among resting, feeding, traveling, and social behavior. Comparisons between species, populations, or individuals can reveal divergences in adaptive strategies and current stressors, and reflect responses to such diverse pressures as predation, thermoregulation, nutrition, and social needs. Further, variation across seasons is an important part of behavioral strategies to survive food scarcity; this can involve increasing or decreasing effort. We documented activity over the 24‐h cycle for the cathemeral, frugivorous Eulemur fulvus and the diurnal, folivorous Propithecus diadema across 13–18 months at Tsinjoarivo, Madagascar. Their activity budgets were dominated by resting (E. fulvus: 74.1%; P. diadema: 85.2%), followed by feeding (15.8%, 12.4%), traveling (9.31%, 1.74%) and social activities (0.76%, 0.70%), respectively. The lower feeding and higher resting in P. diadema likely reflect slower gastrointestinal transit and higher reliance on microbial fermentation to extract energy from fibrous food. The two species showed opposite lean season strategies. E. fulvus increased activity, with more feeding but less travel time, consistent with a shift to less‐profitable fruits, and some leaves and flowers, while increasing feeding effort to compensate ("energy maximizing"). P. diadema showed less variation across months, but the lean season still evoked reduced effort across the board (feeding, travel, and social behavior), consistent with a "time minimizing" strategy prioritizing energy conservation and microbe‐assisted digestion. Understanding these divergent shifts is key to understanding natural behavior and the extent of behavioral flexibility under stressful conditions. Finally, the complex patterns of fruit availability (intra‐ and interannually) and the species' behavioral responses across months underscore the need to move beyond simplistic "lean/abundant season" and "fruit/leaf" dichotomies in understanding underlying energetic strategies, and species' vulnerability to habitat change. Research Highlights: Sympatric lemurs with differing ecologies differ in activity allocation: frugivorous brown lemurs feed and travel more than folivorous diademed sifakas, likely reflecting their fast gut passage and need to travel to reach fruit sources.During lean seasons, when preferred foods (fruits) are scarce, they show opposite responses: brown lemurs increased feeding but decreased travel (energy maximizing) while diademed sifakas reduce both feeding and travel, a time minimizing approach.Activity budgets are easy‐to‐collect, useful tools for comparing species, populations, and individuals, and changes across time are important for understanding energetic strategies, but data sets must be comparable (ideally across the 24‐h cycle). [ABSTRACT FROM AUTHOR]

Objective: Lily is an essential ornamental flowering species worldwide. Drought stress is a major constraint affecting the morphology and physiology and lily leaves and flowers. Therefore, understanding the molecular mechanism underlying lily response to drought stress is important. Method: Transcriptome and metabolome analysis were performed on Oriental Lily subjected to drought stress. Result: Most transcription factors and metabolites yielded by the conjoint analysis displayed a downregulated expression pattern. Differential genes and metabolites mainly co-enriched in glycolic pathways related to sugars, such as galactose, and sucrose, glycolysis and gluconeogenesis, indicating that drought stress reduced the sugar metabolism level of Oriental Lily. Combined with transcriptome and metabolome data, nine pairs of differentially expressed metabolites and the genes (p < 0.05) were obtained. Interestingly, a gene named TRINITY_DN2608 (encoding a type of alpha-D-glucose) cloned and its overexpression lines in Arabidopsis thaliana was generated. Overexpression of TRINITY_DN2608 gene elevated the susceptibility to drought stress possibly by suppressing the glucose level. Conclusion: The enrichment of sugar-related pathways advocates the potential role of glucose metabolism in drought stress. Our study provides theoretical information related to the glucose-mediated drought response and would be fruitful in future lily breeding programs. [ABSTRACT FROM AUTHOR]

The air pollutant NO2 is one of the major constraints on plant growth, and the ecological value of the ornamental plant Bougainvillea glabra can be weakened by NO2. In this study, an indoor 4 μL·L−1 NO2 simulated fumigation test was conducted with three treatments, CK (normal growth with clean air), T1 (4 μL·L−1 NO2 + 8 h/d), and T2 (4 μL·L−1 NO2 + 24 h/d), which were set up with considerations for time and concentration. The results demonstrated that most of the morphological parameters of B. glabra 'Elizabeth Angus', except for the floral organs, were decreased in the root, stem, leaf, and bract. Continuous fumigation significantly attenuated the growth rate and reduced the water and pigment contents of organs. Excessive NO2 reduced the number and transfer rate of photoelectrons by destroying the photosynthetic reaction center, which in turn weakened photosynthesis, but the plants with intermittent fumigation recovered after fumigation. The Kaplan-Meier (K-M) survival curve displayed median survival periods of 41 and 55.5 h for T1 and T2, respectively, and the morphological structure and most of the indicators of photosynthetic reaction centers changed significantly during stress. Acute injury to B. glabra 'Elizabeth Angus' was caused by 4 μL·L−1 NO2, and B. glabra 'Elizabeth Angus' had limited ability to regulate high concentrations of NO2 acute stress. [ABSTRACT FROM AUTHOR]

Indocalamus, characterized by its expansive leaves, low height, strong reproductive capacity, and abundant bioactive compounds, has extensive utility in the realms of food processing, the manufacturing of packaging materials, and the advancement of novel pharmaceuticals. Two light environments, CK (100% full light) and ST (50% full light), were established to explore the effects of low-light environments on the reproductive ability, morphological characteristics, photosynthetic properties, and leaf active substances of 14 Indocalamus species. The findings revealed that in comparison to the CK treatment, for 14 species of Indocalamus under the ST treatment, (1) the diameter, single leaf area, and leaf area index increased by 8.27%, 8.14%, and 17.88%, respectively; (2) the net photosynthetic rate decreased by 15.14%, and the total chlorophyll contents increased by 20.25%; and (3) the total flavonoid contents increased by 18.28% in autumn, the total polyphenol contents increased by 48.96% in spring, and the total polysaccharide contents increased by 31.44% and 30.81% in summer and winter, respectively. In summary, Indocalamus are adapted to survive in low-light environments; the growth and physiological indices differ significantly between the two light environments, and the low-light environment can effectively promote the growth and development of the leaves. Furthermore, the leaves are rich in flavonoids, polyphenols, polysaccharides, and active substances, which are affected by the light intensity and the season to varying degrees, and autumn and winter are the best times for harvesting the leaves. The leaves of I. hunanensis and I. lacunosus are richest in flavonoids and polyphenols, while the leaves of I. kunmingensis cv. fuminer are richest in polysaccharides. The main findings of this study demonstrate that Indocalamus has strong shade tolerance and tremendous leaf value, laying the foundation for broadening the application of their leaves and for their industrial development in understory composite planting systems. [ABSTRACT FROM AUTHOR]

Grapevine leaves contain abundant CaOx crystals located either within the mesophyll in the form of raphides, or in the bundle sheaths as druses. CaOx crystals function as internal carbon pools providing CO2 for a baseline level of photosynthesis, named "alarm photosynthesis", despite closed stomata; thus, preventing the photoinhibition and the oxidative risk due to carbon starvation under adverse conditions. Structural and functional leaf traits of acclimated grapevine plants (Vitis vinifera L. cv. Assyrtiko) were investigated in response to water availability, in order to evaluate the dynamic functionality of CaOx. Leaf water potential, leaf area, leaf mass per area, stomatal properties, gas exchange parameters and performance index (PI) were decreased in leaves of vines acclimated to water deficit in comparison to the leaves of well-irrigated vines, although the chlorophyll fluorescence parameters showed that the operational efficiency of the photosystem II (PSII) photochemistry (Fv/Fm) did not change, indicating that the photosynthetic apparatus was not subjected to water stress. During the afternoon, more than half of the morning's existing druses disappeared in the drought-acclimated leaves. Also, the raphides' area of the drought-acclimated leaves was reduced more than that of the well-watered leaves. The substantial decomposition of druses under water deficit conditions compared to that of the raphides may have important implications for the maintenance of their different though overlapping roles. According to the results, it seems likely that, under water deficit conditions, a mechanism of "alarm photosynthesis" provides an additional tolerance trait in the leaves of Vitis vinifera cv. Assyrtiko; hence, leaf structure relates to function. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.) is one of the most significant staple foods worldwide. Carbohydrates, proteins, vitamins, and minerals are just a few of the many nutrients found in domesticated rice. Ensuring high and constant rice production is vital to facilitating human food supplies, as over three billion people around the globe rely on rice as their primary source of dietary intake. However, the world's rice production and grain quality have drastically declined in recent years due to the challenges posed by global climate change and abiotic stress-related aspects, especially drought, heat, cold, salt, submergence, and heavy metal toxicity. Rice's reduced photosynthetic efficiency results from insufficient stomatal conductance and natural damage to thylakoids and chloroplasts brought on by abiotic stressor-induced chlorosis and leaf wilting. Abiotic stress in rice farming can also cause complications with redox homeostasis, membrane peroxidation, lower seed germination, a drop in fresh and dry weight, necrosis, and tissue damage. Frequent stomatal movements, leaf rolling, generation of reactive oxygen radicals (RORs), antioxidant enzymes, induction of stress-responsive enzymes and protein-repair mechanisms, production of osmolytes, development of ion transporters, detoxifications, etc., are recorded as potent morphological, biochemical and physiological responses of rice plants under adverse abiotic stress. To develop cultivars that can withstand multiple abiotic challenges, it is necessary to understand the molecular and physiological mechanisms that contribute to the deterioration of rice quality under multiple abiotic stresses. The present review highlights the strategic defense mechanisms rice plants adopt to combat abiotic stressors that substantially affect the fundamental morphological, biochemical, and physiological mechanisms. [ABSTRACT FROM AUTHOR]

Tinospora sagittata is a columbin-rich medicinal plant, but its columbin levels are reduced under artificial cultivation conditions. The objective of this study was to analyze the effects of inoculations with Diversispora versiformis (Dv), Funneliformis mosseae (Fm), Rhizophagus intraradices (Ri), and mixed inoculation (Dv + Fm + Ri) (Mix) on growth performance, root morphology, leaf photosynthetic physiology, and root columbin levels in T. sagittata. These arbuscular mycorrhizal fungi (AMF) were able to colonize the roots, as evidenced by a root mycorrhizal colonization rate ranging from 17% to 48% and soil hyphal lengths ranging from 17.51 cm/g to 32.02 cm/g, with the Mix treatment being the greatest. AMF inoculations improved plant height (16–151%), leaf number (119–283%), shoot (37–211%), and root biomass (22–318%) to varying extents, with Ri and Mix treatments being the most prominent. AMF-treated plants presented relatively greater root total length, projected area, surface area, volume, and average diameter, especially those treated with Ri and Mix. AMF inoculations also significantly improved the leaf nitrogen balance index, transpiration rate, and stomatal conductance, while the photosynthesis rate and chlorophyll index varied by AMF species, along with a decrease in intercellular CO2 levels. Root columbin levels ranged from 0.524 mg/g to 5.389 mg/g, and AMF inoculation significantly increased root columbin levels by 228–928%, with Ri being the most significant. Root columbin levels were significantly positively correlated with soil hyphal length, root total length, root projected area, root surface area, root volume, and root average diameter, but not root AMF colonization rate. This study demonstrates for the first time that AMF, especially Ri, can be employed as a biostimulant to promote growth as well as root columbin levels in T. sagittata, where AMF-triggered improvement in root morphology is an important reason for promoting root columbin levels. [ABSTRACT FROM AUTHOR]