Leaf Relative Water Content Research Articles

Effects of exogenous spraying of melatonin on the growth of Platycrater arguta under drought stress

Platycrater arguta is a rare and endangered deciduous shrub originating from the Tertiary Period. Understanding its drought tolerance is crucial for conservation efforts and enhancing its resilience to environmental stress. This study aimed to assess the effects of varying levels of drought stress on the phenotype and physiological–biochemical characteristics of P. arguta. The study subjected P. arguta to different levels of drought stress using 10%, 20%, and 30% polyethylene glycol-6000 (PEG-6000) over a 10-day period. Additionally, the effects of exogenous melatonin application at various concentrations (including 100 µM) were examined to determine its potential in alleviating drought-induced damage. Key parameters measured included leaf relative water content, net photosynthetic rate (Pn), antioxidant enzyme activity, and soluble sugar content. Drought stress significantly inhibited the growth of P. arguta. As PEG-6000 concentration increased, leaf relative water content and net photosynthetic rate decreased, while leaf wilting severity, membrane damage, antioxidant enzyme activity, and soluble sugar content increased. A 30% PEG-6000 concentration caused irreversible damage, leading to plant death. Exogenous application of 100 µM melatonin alleviated this damage by increasing leaf relative water content, enhancing photosynthetic efficiency, boosting antioxidant enzyme activity, accumulating osmotic regulators, and reducing leaf desiccation. The study demonstrated that P. arguta is sensitive to severe drought conditions, with 30% PEG-6000 causing irreversible damage. However, the application of 100 µM melatonin significantly improved the plant's drought tolerance by upregulating the expression of ABI1 and downregulating genes such as AUX1A-2, IAA2-2, and HP2-1. This finding highlights the potential of melatonin as a protective agent against drought stress, providing valuable insights for the conservation and enhancement of P. arguta's resilience to environmental challenges.

Construing the resilience to osmotic stress using endophytic fungus in maize (Zea mays L.).

In a wake of shifting climatic scenarios, plants are frequently forced to undergo a spectrum of abiotic and biotic stresses at various stages of growth, many of which have a detrimental effect on production and survival. Naturally, microbial consortia partner up to boost plant growth and constitute a diversified ecosystem against abiotic stresses. Despite this, little is known pertaining to the interplay between endophytic microbes which release phytohormones and stimulate plant development in stressed environments. In a lab study, we demonstrated that an endophyte isolated from the Kargil region of India, a Fusarium equiseti strain K23-FE, colonizes the maize hybrid MAH 14 - 5, promoting its growth and conferring polyethylene glycol (PEG)-induced osmotic stress tolerance. To unravel the molecular mechanism, maize seedlings inoculated with endophyte were subjected to comparative transcriptomic analysis. In response to osmotic stress, genes associated with metabolic, photosynthesis, secondary metabolites, and terpene biosynthesis pathways were highly upregulated in endophyte enriched maize seedlings. Further, in a greenhouse experiment, maize plants inoculated with fungal endophyte showed higher relative leaf water content, chlorophyll content, and antioxidant enzyme activity such as polyphenol oxidase (PPO) and catalase (CAT) under 50% field capacity conditions. Osmoprotectant like proline were higher and malondialdehyde content was reduced in colonized plants. This study set as proof of concept to demonstrate that endophytes adapted to adverse environments can efficiently tweak non-host plant responses to abiotic stresses such as water deficit stress via physiological and molecular pathways, offering a huge opportunity for their deployment in sustainable agriculture.

A Comparative Study on Drought Stress Response In Vitro and In Vivo Propagated Fragaria vesca Plants

The evaluation of plant responses to water deficit in the substrate, particularly in the context of intensifying climate change, represents a critical factor for ensuring stable agricultural production, economic resilience, and food security. The primary objective of this study was to compare the physiological and biochemical responses to water deficit in conventional cultivation of Fragaria vesca plants propagated both in vitro and in vivo. The research encompassed measurements of gas exchange parameters, chlorophyll “a” fluorescence, photosynthetic pigment and proline content in leaves, leaf relative water content index, total fruit yield, single fruit weight, fresh and dry mass of the root system, as well as the concentrations of K, Ca, Mg, Na, Cu, Zn, Mn, and Mo. Additionally, the ratio of monovalent to divalent cations in leaves, roots, and crowns was analyzed. The results revealed significant differences between the experimental variants under optimal conditions and their respective responses to drought stress. Plants derived from in vitro cultures, despite exhibiting initially lower physiological trait values, demonstrated higher yield potential (no significant difference in the yield of fresh fruit mass compared to a 78% reduction). However, a long-term lack of water caused greater damage to their photosynthetic system—a reduction in physiological traits to 80% was observed, compared to a maximum decrease of 40% in plants derived from seedlings. The results highlight that environmental conditions and the acclimatization process of plants derived from in vitro cultures can significantly influence their adaptive potential and productivity.

Differential biochemical responses of seven Indian wheat genotypes to temperature stress

BackgroundChanges in the temperature induction response are potential tools for the empirical assessment of plant cell tolerance. This technique is used to identify thermotolerant lines in field crops. In the present investigation, ten-day-old seedlings of six wheat genotypes released by Dr. PDKV, Akola, Maharashtra, India were exposed to gradual increases in high temperature and duration (control 25 °C to 30 °C for 1 h, 34 °C for 1 h, 38 °C for 2 h and 42 °C for 3 h) to investigate their effects on some physiological and biochemical parameters to provide basic information for improving heat-tolerant cultivars.ResultsProline levels increased with increasing temperature up to 34 °C for 1 h but then decreased at higher temperatures (depending on genotype). Notably, proline levels decreased at 38 °C for 2 h in PDKV-Washim, AKAW-3722, and PDKV Sardar and at 42 °C for 3 h in all the genotypes. The relative leaf water content (RLWC) and chlorophyll 'b' content significantly decreased with increasing temperature. Hydrogen peroxide (H₂O₂) levels increased with temperature. The enzyme activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), and peroxidase also increased with temperature. However, these parameters, along with other biochemical indicators, generally decreased at 42 °C for 3 h.ConclusionThis study revealed positive relationships between increasing temperatures. Hydrogen peroxide levels and the activities of SOD, APX, and peroxidase enzymes across all the genotypes. The AKAW-4627 genotype presented better maintenance of physiological and biochemical parameters and lower H₂O₂ levels, indicating greater heat tolerance. Compared with PDKV-Washim and AKAW-3722, which are more susceptible to high temperatures, the WSM-109–04, AKAW-4627 and PDKV Sardar genotypes presented better adaptability to heat stress. These findings suggest that selecting wheat genotypes with higher proline accumulation and better maintenance of physiological and biochemical parameters under heat stress, such as AKAW-4627, can help in the development of heat-tolerant wheat cultivars.

Morpho-Physiological Adaptations of Drought-Resilient and Susceptible Brassica napus Genotypes to Sulphur-Coated Urea Fertilization

This study focuses on screening drought-tolerant and sensitive genotypes of Brassica napus L. (an important oilseed crop in Pakistan) and investigates their morpho-physiological responses to sulphur-coated urea (SCU) under drought conditions. Genotypes were categorized into highly drought tolerant (HDT), moderately drought tolerant (MDT), and highly drought sensitive (HDS) through hierarchical cluster analysis. Out of 100 genotypes, 20 were HDT, 30 were MDT, and 50 were HDS. Three genotypes from each category were subjected to two drought levels (80% field capacity and 50% field capacity) and were treated with SCU, urea, or no nitrogen. Key parameters such as leaf relative water content, chlorophyll content, excised leaf water loss, and membrane stability index (MSI) were recorded. Drought-tolerant genotypes performed well in both germination and seedling stages, showing higher excised leaf water loss, relative water content, chlorophyll values, seed weight, and yield-related traits. Initially, five concentrations of PEG-6000 (5% to 25%) were tested to determine optimal levels for screening drought tolerance. Results showed that 25% PEG-6000 induced 50% drought injury index (DII), making it the most promising concentration. Various morpho-physiological traits such as germination rate, shoot/root length, fresh and dry weight, and drought tolerance indices were assessed. The study concluded that drought-tolerant genotypes responded positively to SCU application, making them suitable for cultivation in water-scarce regions of Pakistan.

Effects of Water and Nitrogen on Eco-physiological Characteristics of Two Dominant Grassland Species on the Semiarid Loess Plateau

To investigate the eco-physiologcial traits in response to water and nitrogen supplying conditions of native species is of importance for understanding their eco-adaptation to the local environment, and also finding rational agronomy measures for using them in artificial grassland construction. In this study, using Bothriochloa ischaemum (C4 grass) and Lespedeza davurica (C3 legume) as research materials, a pot experiment was conducted to compare the leaf photosynthetic traits, leaf fluorescence parameter characteristics and leaf relative water content of the two dominant native species under three different soil moisture conditions (80%FC, 60%FC and 40%FC) and two nitrogen supplying (0 g N kg-1 and 0.025 g N kg-1) conditions when sown individually or in mixture. Results showed that as soil water content decreased from 80% FC (field capacity) to 40% FC, leaf net photosynthetic rate (Pn), transpiration rate (Tr), intercellular CO2 concentration (Ci), and stomatal conductance (Gs) of monocultured plants showed an increasing trend, while the photosynthetic parameters of mixculture plants generally exhibited a decreasing trend. The Pn values of L. davurica were significantly higher than those of B. ishchaemum (P<0.05), and the maximum value was 12.50 mmol m-2 s-1. As soil water content decreased, the initial fluorescence values (Fo), maximum potential quantum yield of PSII (Fv/Fo), and maximum photochemical efficiency (Fv/Fm) values under no nitrogen treatment showed no significant change (P>0.05). Overall, the data indicated that when B. ischaemum and L. davurica were mixcultured, there existed a significant mutualistic effect under low soil water situation, indicating mixculture of B. ischaemum and L. davurica was beneficial for coping with drought in the semiarid region.

Silicon Nanoparticles (SiO2 NPs) Boost Drought Tolerance in Grapevines by Enhancing Some Morphological, Physiological, and Biochemical Traits

AbstractDrought is a significant abiotic stress that adversely affects plant growth, development, and metabolic processes, posing a global threat to food security. In recent years, nanotechnology has emerged as a promising strategy to mitigate environmental challenges and has been tested on various plant species; however, its application to grapevines remains largely unexplored. This study aims to investigate the potential of silicon nanoparticles (SiO2 NPs) to modulate morphological, physiological, and biochemical parameters in grapevine saplings (5 BB/Crimson Seedless, 41 B/Crimson Seedless, and 1103 P/Crimson Seedless) under drought stress conditions. Saplings were treated with foliar applications of different concentrations of SiO2 NP solutions (0 (control), 1, 10, and 100 ppm) under well-irrigated (90–100% field capacity) and drought stress (40–50% field capacity) conditions. The results indicated that the application of SiO2 NPs at 10 ppm concentration enhanced growth parameters (such as leaf area, leaf number, shoot fresh and dry weight, root fresh and dry weight) and chlorophyll content under both well-irrigated and drought conditions. Additionally, there was an improvement in leaf relative water content (RWC) and stomatal conductance, correlating with increased protein content. Under drought conditions, oxidative stress indicators, including drought index, leaf temperature, membrane injury index, hydrogen peroxide (H2O2) content, and malondialdehyde (MDA) levels, showed a significant decrease. Concurrently, proline content, total phenolic compounds, and activities of antioxidant enzymes (SOD, CAT, and APX), which increased under drought stress, were reduced in the presence of 10 ppm SiO2 NPs, suggesting a mitigation of oxidative stress. To comprehensively evaluate the effects of SiO2 NP concentrations, irrigation regimes, and rootstock/variety combinations, correlation analysis, principal component analysis (PCA), and hierarchical clustering heatmap analysis were performed. Collectively, the findings suggest that the observed drought-induced oxidative stress tolerance in grapevine saplings in the presence of 10 ppm SiO2 NPs may result from the influence of antioxidant systems leading to a balanced redox potential. These results support the argument that SiO2 NPs play a crucial role in enhancing drought tolerance, with implications for managing drought stress in other agricultural crops as well.

Plant Growth-Promoting Rhizobacteria Paenibacillus polymyxa HL14-3 Inoculation Enhances Drought Tolerance in Cucumber by Triggering Abscisic Acid-Mediated Stomatal Closure.

Drought limits crop growth and yield. Inoculation with plant growth-promoting rhizobacteria (PGPR) emerges as a promising strategy to protect crops against drought. However, the number of drought-tolerant PGPR is limited, and the regulation mechanisms remain elusive. Here, we screened a novel drought-tolerant PGPR strain Paenibacillus polymyxa HL14-3 with high drought-tolerance potential and efficient colonization ability. P. polymyxa HL14-3 inoculation effectively alleviated drought-induced growth inhibition and oxidative stress and improved the root system architecture in cucumber. Furthermore, P. polymyxa HL14-3 improved stomatal closure and leaf relative water content, reducing water loss in cucumber under drought stress. Importantly, P. polymyxa HL14-3 inoculation enhanced drought tolerance in cucumber by inducing abscisic acid synthesis, which was counteracted by root irrigation with the ABA synthesis inhibitor fluridone. Together, our results demonstrate that P. polymyxa HL14-3 inoculation enhances drought tolerance in cucumber by triggering ABA-mediated stomatal closure, providing an effective drought-tolerant PGPR for promoting agricultural production in arid areas.

Impact of Irrigation Cessation on Physiological, Photosynthetic, and Enzymatic Activities in Wheat (Triticum aestivum L.) at Varying Plant Densities

Drought stress is one of the most critical factors reducing the performance of crop plants in arid and semi-arid regions globally, highlighting the importance of understanding underlying mechanisms to combat such stress. Therefore, this experiment aimed to investigate the effect of drought stress and planting density on the physiological characteristics, photosynthetic pigments, and enzymatic activity of wheat plants. The experiment was conducted in a factorial arrangement based on a completely randomized block design with three replications. The treatments included irrigation cessation at three levels (control, irrigation until flowering (IUF), and irrigation until the roughing (IUD)), and plant density (300, 400, 500, and 600 plants m-2). The results indicated that leaf relative water content, soluble sugars, cell membrane stability index, chlorophyll a, b, and carotenoids were significantly decreased at IUF treatment, while these parameters increased at higher plant densities. Additionally, the interaction of drought stress and plant density significantly affected leaf proline and flavonoid content, total chlorophyll, and catalase activity. The highest leaf proline content (3.88 mg g-1 FW) was observed in the treatment with IUF and a density of 600 plants m-2, representing a 192% increase compared to the control. Additionally, the highest total chlorophyll content (3.66 mg g-1 FW) was recorded at no-stress conditions with a density of 500 plants m-2. Under drought stress conditions, the activity of antioxidant enzymes also increased. Overall, our results indicate that a density of 500 plants m-2 is optimal for maintaining stable growth conditions in wheat. These findings provide valuable insights for policymakers to develop effective agronomic strategies to mitigate drought stress, particularly in arid and semi-arid regions.

Genotyping-by-sequencing uncovers a Thinopyrum 4StS·1JvsS Robertsonian translocation linked to multiple stress tolerances in bread wheat

KeymessageGBS read coverage analysis identified a Robertsonian chromosome from twoThinopyrumsubgenomes in wheat, conferring leaf and stripe rust resistance, drought tolerance, and maintaining yield stability.Agropyron glael (GLAEL), a Thinopyrum intermedium × Th. ponticum hybrid, serves as a valuable genetic resource for wheat improvement. Despite its potential, limited knowledge of its chromosome structure and homoeologous relationships with hexaploid wheat (Triticum aestivum) has restricted the full exploitation of GLAEL's genetic diversity in breeding programs. Here, we present the development of a 44-chromosome wheat/GLAEL addition line (GLA7). Multicolor genomic in situ hybridization identified one chromosome arm from the St subgenome of Th. intermedium, while the other arm remained unclassified. Genotyping-by-sequencing (GBS) read coverage analysis revealed a unique Robertsonian translocation between two distinct Thinopyrum subgenomes, identified as 4StS·1JvsS. The GLA7 line demonstrated strong adult plant resistance to both leaf rust and stripe rust under natural and artificial infection conditions. Automated phenotyping of shoot morphological parameters together with leaf relative water content and yield components showed that the GLA7 line exhibited elevated drought tolerance compared to parental wheat genotypes. Three years of field trials showed that GLA7 exhibits similar agronomic performance and yield components to the wheat parents. This unique addition line holds promise for enhancing wheat's tolerance to multiple stresses through the introduction of new resistance genes, as well as its ability to mitigate the effects of temporary water limitation during flowering, all without negatively impacting wheat performance.

Effect of Supplemental UV-B Radiation and Water Limitation on Plant Growth, Yield and Berry Composition of the Greek Grapevine Cultivar “Romeiko” Under Mediterranean Field Conditions

This work aims to evaluate the performance of the grapevine (Vitis vinifera L.) cultivar Romeiko under the influence of limited water availability and additional UV-B radiation exposure, applied alone or in combination. Three-year-old grapevines were exposed to two water regimes (well watered and water stressed) and two levels of UV-B radiation (ambient UV-B and ambient plus 15% UV-B). Predawn leaf water potential (ΨPD) and leaf relative water content (RWC) were significantly higher in well watered plants and on the other hand, no significant effect of UV-B on leaf tissue hydration was revealed. Both abiotic stressors significantly affected shoot growth rate (SGR), leaf fresh weight (FW) and leaf dry eight (DW), with the effect of water shortage on vegetative growth being more pronounced. Deficit irrigation had negative effects on yield both because of the reduced berry fresh weight and the lesser number of berries per cluster, while the yield response (quantity and quality attributes) of cv. Romeiko was similar between the two UV-B radiation regimes. In summary, limited water supply had a high potential for restricting vegetative growth and yield, whereas the effects of enhanced UV-B radiation were less evident on allometric parameters and nonexistent on fruit yield and quality characteristics. In addition, the combination of supplemental UV-B and deficit irrigation did not cause any pronounced effects compared to the single application of limited water supply.

A Comparative Study on Rapeseed Sprayed with Film Antitranspirant Under Two Contrasting Rates of Soil Water Depletion

Rapeseed (Brassica napus L.), as one of the most important oil crops around the world, has been affected by drought considerably, particularly at flowering when crops are most sensitive to water stress. It has been shown that film antitranspirant (AT) can effectively reduce the yield loss of droughted crops if applied at the critical stage. However, the mechanism remains unclear by which AT mitigates drought damage to plants under different rates of water depletion. Two experiments in randomised complete block designs were conducted on spring rapeseed with two levels of irrigation, well-watered (WW) and water-stressed (WS), where slow and fast soil water depletion were imposed during the flowering stage in mesocosms (Expt 1_SD) and pots (Expt 2_FD), respectively, and different concentrations of AT, 0, 0.25%, 0.5%, and 1% and 0, 0.5%, and 1%, were applied. Leaf physiological traits, seed yield, and yield components were determined. The results showed that compared to WW, water stress reduced leaf relative water content (RWC) by 2% and 6% in Expt 1_SD and Expt 2_FD, respectively, and had detrimental effects on stomatal conductance, CO2 assimilation rate, and intrinsic water use efficiency. Following AT application, a positive linear relationship was observed in leaf RWC against AT concentrations, albeit with large variations. In Expt 1_SD, seed dry weight and aboveground biomass increased significantly with increasing AT concentrations, while no yield responses were observed in Expt 2_FD, indicating that soil water status may play an important role in rapeseed responses to AT application regardless of concentrations. Therefore, the timing of AT application needs to consider soil water conditions in addition to the growth development of rapeseed plants.

Variability Studies in Soybean Genotypes under Different Water Regimes

Soybean (Glycine max L.) is economically one of the most important oilseed crop worldwide which have high protein and oil content. Its productivity is frequently affected due to drought occurrence in India. Variability for root shoot traits under early seedling stage under drought stress may be important selection criteria for development of drought tolerant genotypes. The present investigation was carried out at Net house of Experimental Farm, Mandsaur University, Mandsaur. Sixty genotypes, procured from ICAR-IISR, were used to know the extent of genetic variability under different water regimes [normal, 100 ml (100%), S1, 50 ml (50%), S2, 25 ml (25%) and S3,0 ml (0%)] for root-soot traits and relative leaf water content under early seedling stage. Significant genetic variability was recorded for all the traits among genotypes studied under normal and water stress conditions respectively which showed the presence of ample variability in studied material. High Phenotypic Coefficient of Variation than their corresponding Genotypic Coefficient of Variation for the entire trait under different water regimes denoted influence of environment on these traits. The large genetic variation found in these genotypes may be used to develop varieties with better drought tolerance behavior and used as drought donor lines in drought breeding programs. We measured high heritability for selected characters under non water stress condition (75.05% to 100%) and water stress conditions S1 (81.40% to 100%), S2 (85.69% to 100%) and S3 (92.60% to 99.26%) respectively. Additive gene action interacted to control characters under different water regimes because high broad sense heritability along with high genetic advance as percentage of mean were recorded for most of traits. It is indicating that simple phenotypic selection would be effective for these traits under water stress condition.

Exploration of Agronomic Efficacy and Drought Amelioration Ability of Municipal Solid-Waste-Derived Co-Compost on Lettuce and Maize

Organic soil amendments, such as composts, mitigate the negative impacts on the environment that are caused by poor waste management practices. However, in the sub-Saharan African region, and Malawi in particular, studies investigating the agronomical efficacy and their ability to ameliorate drought stress when used as a soil amendment are minimal. This study aimed to evaluate the efficacy of sewage sludge and municipal solid waste (MSW) co-compost to ameliorate drought stress and improve crop productivity. Three experiments were conducted (i) to determine optimal application rate for co-compost, (ii) to evaluate yield response of maize and lettuce to co-compost application under contrasting soils, and (iii) to assess the effect of co-compost under water-limited conditions. Our results indicate that an application rate of 350 g co-compost per station was the most effective. This rate is 50% and 37% lower than the currently recommended rate for applying conventional compost to green vegetables and maize, respectively. In addition, under drought conditions, the co-compost application enhanced growth in lettuce, with less wilting, increased biomass and yield, approximately 130% greater leaf yield, and a 138% improvement in root growth. Furthermore, the relative root mass ratio (RRMR) was enhanced with the co-compost application by 103% under drought stress. This suggests that the co-compost amendment resulted in a greater allocation of biomass to the roots, which is a crucial morphological attribute for adapting to drought conditions. The concentration of K in the leaves and roots of plants treated with co-compost was significantly increased by 44% and 61%, respectively, under drought conditions, which may have contributed to osmotic adjustment, resulting in a significant increase in leaf relative water content (RWC) by a magnitude of 11 times. Therefore, in light of the rising inorganic fertilizer costs and the limited availability of water resources, these results demonstrate the potential of MSW and sludge co-composting in ameliorating the drastic effects of water- and nutrient-deficient conditions and optimizing growth and yield under these constraining environments.

The Application of Stress Modifiers as an Eco-Friendly Approach to Alleviate the Water Scarcity in Ajwain (Carum copticum L.) Plants.

Stress modifiers are recognized as biostimulants providing beneficial effects on various plant species. However, the specific potential of modulators such as melatonin, chitosan, humic acid, and selenium in enhancing the resistance of ajwain (Carum copticum L.) plants to water scarcity remains an open question. To address this knowledge gap, we conducted a randomized, field block-designed factorial experiment over two years (2022-2023) to compare the effectiveness of these biostimulants in mitigating the impact of water shortage on ajwain plants. This study involved three irrigation regimes: 100% field water capacity (FC100%-unstressed), 75% irrigation deficit (FC75%-moderate) and 50% irrigation deficit (FC50%-severe), and four modifier treatments (melatonin, chitosan, humic acid, selenium), plus untreated controls. Plant growth, seed yields, essential oil production, as well as eco-physiological traits were studied to assess the efficacy of these compounds as stress modulators. Water regimes and stress modifier applications, as a single factor or in synergy, significantly affected plant physiology and seed yield, highlighting the importance of sustainability in agricultural practices. Compared to FC100%, biological and seed yield, chlorophyll, and nutrient content decreased under FC75% and FC50%, while essential oil production, proline, soluble sugars, flavonoids, phenols and antioxidant enzymatic activity increased. Notably, regardless of the type of modulator used, the application of these modifiers improved all physiological attributes under moderate and severe irrigation deficits. Among the involved compounds, melatonin induced the most pronounced effects, leading to higher biological and seed yield, essential and fixed oil production, relative leaf water content, chlorophyll and nutrient concentration, and antioxidant activity. Our results demonstrate that such compounds effectively function as stress modulators against water scarcity in ajwain plants by preserving specific eco-physiological traits and promoting water saving. These findings provide valuable insights into their use as a nature-based solution for addressing water stress in sustainable agriculture and climate change challenges.

Maize growth and physiological dynamics: Arsenic uptake modulation under combined abiotic stresses of salinity, boron and arsenic

Soil salinity and relatively high boron (B), frequently co-occur in agricultural environments, posing significant challenges to crop growth and productivity. This inhibitory effect on plant growth can be further exacerbated when crops like maize (Zea mays L.) are exposed to the arsenic (As) contaminated soils and irrigation water, along with elevated salinity and B levels. Understanding these combined effects is crucial for optimizing crop resilience. A hydroponic study was conducted to assess the interactive effects of high B and As under saline conditions on maize. Plants were stressed with salinity (60 mM NaCl), boron (3 mM H3BO3) and arsenic (40 µM Na3AsO4) alone and in combination. A 20-day stress period caused significant reduction in overall growth, with more pronounced effect under combined stress. Root and shoot dry biomass was decreased by 63.45 and 57.84 % while leaf area and chlorophyll index (SPAD value) were diminished by 56.34 and 64.23 %, membrane stability index (MSI) and leaf relative water contents (RWC %) were reduced by 63.92 and 61.59 % upon exposure to these combined stressors as compared to the control treatment. Arsenic stress increased the shoot and root As accumulation by 52.4 and 84.6-fold, respectively. However, high B and salinity effectively suppressed these levels due to their negative correlation with As uptake. Further in-depth phytometric profiling is needed to understand the underlying mechanisms of plant stress tolerance and nutrient homeostasis under these combined stresses.

A Multifunctional Hydrogel with Multimodal Self-Powered Sensing Capability and Stable Direct Current Output for Outdoor Plant Monitoring Systems

HighlightsA simple and scalable fabricated hydrogel with multiple functionalities to realize self-sustainable outdoor monitoring solely by it for large-scale applications in precision agriculture.Stable direct-current output without requirement on stochastic or temporal environmental energies, achieving an energy density of 1.36 × 107 J m–3 with continuous operation of 56.25 days in normal outdoor environment.Self-powered noninvasive leaf relative water content monitoring and environmental sensing to evaluate plant health status with high durability and self-recoverability in severe environments.

Influence of Sowing Media and Variety on Physiological Performance and Yield of Early Cauliflower (Brassica oleracea L. var. botrytis) and Correlation Study with Yield

An experiment was conducted during 2018 and 2019 at the Experimental Farm, Department of Horticulture, College of Agriculture, Assam Agricultural University, Jorhat and at Farmer’s field to assess the physiological performance of early cauliflower varieties in different sowing media and to evaluate their performance in the field as well as to study the correlation of different physiological parameters with curd yield. The experiment was laid out in Randomized Block Design with eight treatments comprising of four sowing media [M1-cocopeat (60): vermiculite (20): perlite (20), M2-cocopeat (50): vermicompost (50),M3-cocopeat (50): vermicompost (50): microbial consortium @1:100 and M4-Conventional nursery]and two varieties [V1 (White Diamond) and V2 (CFL1522)] replicated thrice. The results revealed that growing medium had significant influence on different physiological parameters of early cauliflower seedling. Maximum chlorophyll content was recorded in M3 (0.98 mg g-1fw), maximum number of stomata in upper and lower surface (83.47and 150.97), relative water content (90.06 %) and dry matter accumulation (11.41 %) were recorded in M2. Between the two varieties, V1 recorded higher stomata number (145.06) in the lower surface. In the main field, the plants grown from M3 showcased superior performance with highest relative water content (93.62%), chlorophyll content at 30 days after transplanting (1.40 mg g-1fw) and at harvest (2.16 mg g-1fw), membrane stability index (65.32%), minimum lipid peroxidation (0.85 n mol g-1fw) at harvest and maximum curd yield (200.22 q/ha). Between the two varieties White Diamond(V1) recorded the higher relative water content (89.48 %) while V2 (CFL 1522) recorded the maximum membrane stability index (55.10%) and non-significant influence of variety was noticed on yield. Correlation coefficient analysis indicated chlorophyll content at seedling stage, crop growth and at harvest stage, relative leaf water content and membrane stability index at harvest have positive and significant correlation with curd yield of cauliflower. The study indicates sowing media had significant influence on physiological parameters of seedlings of early cauliflower which is again reflected in the field condition influencing yield as well and can be concluded that sowing media cocopeat (50): vermicompost (50): microbial consortium @1:100 can be used for nursery raising of early cauliflower seedling in Assam condition.

Altering endogenous cytokinin content by GmCKX13 as a strategy to develop drought-tolerant plants

Climate-resilient crops are essential to meet the growing food demands of an ever-increasing world population. The phytohormone cytokinins (CKs) have been well established to regulate plant adaptation to drought. Previously, we reported that GmCKX13, encoding a CK oxidase/dehydrogenase in soybean (Glycince max), was differentially expressed under drought. Here, we further characterized its in planta function to assess if GmCKX13 could be a candidate gene to develop drought-tolerant crops. Transgenic Arabidopsis 35S:GmCKX13 plants ectopically and constitutively expressing GmCKX13 using the 35S promoter had an increase in root length, while showing a reduction in shoot height and biomass. CK contents were reduced in 35S:GmCKX13 plants, coupled with the reduced expression of all AtCKX genes and increased expression of all Arabidopsis isopentenyl transferase (AtIPT) genes, except AtIPT2 and AtIPT9 that are responsible for the production of cis-zeatin-type CKs. The 35S:GmCKX13 plants showed improved tolerance to drought and more sensitivity to the treatment with exogenous abscisic acid (ABA). Under the control of the drought-responsive promoter RD29A, the transgenic RD29A:GmCKX13 Arabidopsis plants had a similar phenotype as that of the wild-type (WT) plants under normal conditions. Under dehydration, we found a significant increase in the expression of the transgene coupled with a higher leaf relative water content in RD29A:GmCKX13 plants when compared with WT plants. In consistence with this finding, the RD29A:GmCKX13 plants exhibited higher survival rates and 30 % higher seed yield than the WT plants under drought conditions. Taken together, our results demonstrated that GmCKX13 is an excellent gene for developing drought-tolerant crops by altering endogenous CK levels and ABA responsiveness when being driven by a drought-responsive promoter.

Impact of Cow Urine and Substrate Composition on Germination and Early Growth of Papaya (Carica papaya L.) Seedlings

Aim: This study evaluates the impact of cow urine and substrate composition on the germination and early growth of papaya (Carica papaya L.) seedlings, a critical phase for successful crop establishment. Study Design and Methodology: Conducted as a factorial experiment, it assessed eleven substrate or growing media combinations with and without cow urine treatment. Results: Results reveal that cow urine significantly reduces the time to 90 percent germination (T90) and enhances the germination index, indicating its stimulatory effect on seed metabolic activity. Treatments combining cow urine with substrates like soil, sand, vermiculite, cocopeat, and perlite (T10) showed the shortest T90 and highest germination index, suggesting cow urine accelerates germination. Additionally, cow urine application improved growth metrics such as relative growth rate (RGR) and total biomass accumulation, with T10 and T8 treatments yielding the highest values. Enhanced leaf relative water content (LRWC) and elevated proline levels in cow urine-treated plants indicate better water retention and stress resilience. Strong positive correlations were observed among proline content, RGR, and biomass accumulation, highlighting cow urine’s contribution to vigorous seedling growth and stress adaptation. Conclusion: The findings suggest that cow urine, in combination with optimized substrates, is a sustainable growth enhancer that promotes robust seedling development, suitable for organic farming practices aimed at papaya cultivation.