Mitigate Water Stress Research Articles

Co-application of kaolin and superabsorbent polymer mitigate water stress and improves yield and water use efficiency in tomato plant

Water stress is one of the factors that remarkably constrain agricultural productivity in Iran. This experiment aimed to evaluate the effect of Kaolin (KL) and Superabsorbent polymer (SAP) separately or in combination on alleviating harmful effects of water stress on tomato. A factorial experiment was designed with two main factors: irrigation regimes (100, 75 and 50 % of the crop evapotranspiration (ETc)) and drought-alleviating treatments (control, KL, SAP, and KL+SAP) under field condition. Results showed that water deficit (exclusively at 50 % ETc) significantly decreased total fruit yield, water use efficiency (WUE), relative water content (RWC), and chlorophyll content, whereas it increased the rate of osmolyte accumulation, malondialdehyde, and antioxidant enzymes activities. As compared to the other treatments, the interaction of KL+SAP at different irrigation regimes (at 50, 75, and 100 % ETc) raised total fruit yield by 172, 111, and 103 %, respectively. Furthermore, the highest WUE, RWC, and chlorophyll content and conversely the lowest osmolyte accumulation, MDA, and H2O2 content were obtained by KL+SAP treatment at different irrigations. This indicates that co-application of KL and SAP could alleviate the harmful effect of water stress on tomato plant; therefore, it can be used to improve tomato's yield and WUE in areas with drought stress.

Different drought-tolerance strategies of tree species to cope with increased water stress under climate change in a mixed forest.

Trees' functional strategies to cope with extreme drought are essential under climate change. In a mixed Mediterranean forest, we analyzed the functional strategy in response to drought of four co-occurring species (Pinus pinea, Pinus pinaster, Juniperus oxycedrus, and Quercus ilex) during two years. Specifically, we assessed functional traits related to tree water status, leaf water relations, and gas exchange. Different trait-syndrome metrics and the functional strategies under water stress observed suggested a species drought-tolerance differentiation, with the more anysohidric Q. ilex and J. oxycedrus showing a much higher drought tolerance than the more isohydric P. pinea and P. pinaster. All species recovered from negative leaf turgor reached during peak water stress in summer. Q. ilex and J. oxycedrus kept lower leaf osmotic potentials and lower sensitivity of leaf gas exchange and leaf photochemistry to water stress. In contrast, the pine species exhibited more drought-avoidant and water-conservative strategies, yet this behavior was less effective in mitigating water stress's impact on their physiology. The pine species were the most affected by drought, with prolonged near-zero net photosynthesis during summer. P. pinaster was more isohydric than P. pinea and exhibited a lower capacity to maintain leaf turgor. Physiological processes regulating leaf turgor under drought constitute a key functional strategy involved in the carbon and water-related mechanisms, ultimately inducing mortality under hot drought. The currently observed mortality dynamics for P. pinaster, and to a lower extent in P. pinea, may be exacerbated by loss of functional homeostasis.

Growth-promoting rhizobacteria improve physiological variables in lemon balm, Melissa officinalis L., subjected to water stress

Climate change has caused droughts in regions that previously did not have water issues, affecting the production of medicinal plants grown in small-scale agricultural units. Plants such as lemon balm, Melissa officinalis L., are sensitive to water stress, which reduces their yield. One alternative to mitigate water stress is the use of plant growth-promoting rhizobacteria (PGPR). However, in the high tropics of Colombia, the use of these microorganisms is not common due to a lack of knowledge about how they can improve water absorption and increase the yield of medicinal plants. This study aimed to determine the effect of native PGPR on lemon balm plants subjected to water stress conditions using a completely randomized design with six treatments and four replications. Applications of Bacillus cereus and Bacillus amyloliquefaciens were made, and the plants were subjected to two water levels (field capacity and 50% field capacity). Physiological variables of stomatal conductance, chlorophyll content, and fluorescence were measured at the end of the experiment. Bacillus cereus significantly improved growth parameters such as number of leaves (115.00±34.71), fresh weight of root (5.51±3.07 g) and shoot (8.32±4.27), Bacillus amyloliquefaciens increased stomatal conductance (401.3 μmol H2O m2 s1) in water-stressed plants. These results suggest that the use of native PGPR considerably improves the growth and development parameters of lemon balm plants and provides a viable alternative for farmers to enhance yield and resistance to water stress conditions.

A framework for evaluating the combined effects of water transfer and storage strategies on water stress alleviation

Water transfer and storage are two effective anthropogenic management strategies to alleviate the contradictions between water supply and demand. However, the trade-off and synergistic impacts of management strategies in alleviating water stress remain unclear at the national level. Therefore, this study proposes a framework that integrates the fraction of runoff being withdrawn (scarcity coefficient) and the variation of runoff weighted by reservoir (variability coefficient) to evaluate the multifaceted impacts of management strategies on water stress mitigation. The proposed framework evaluates the changes in both the water supply–demand balance and the historical variability of runoff by considering physical water transfers, virtual water flows, and reservoir operations. This study applied the framework to evaluate the spatiotemporal patterns of water stress and used principal component analysis to estimate the relative contributions of management strategies across ten first-order basins in China for the period of 2014–2018. Results show that water-resource scarcity coefficient varied between −37.15% and 13.28% at the basin scale (the national average varied −5%) and water-resource variability coefficient varied between −100% and −19.26% at the basin scale (the national average varied −61.11%). Management strategies, incorporating water transfer and storage strategies, shifted the distribution patterns of national water stress. The attribution analysis revealed that reservoir storage capacity was the largest contributor to the first principal component representing infrastructure element, whereas the second component representing economic element was affected by the net virtual water inflows. Overall, through exploring the outcomes of combined effects among management strategies, this proposed framework provides a comprehensive perspective for investigating how human activity alleviates regional water stress.

Identification of critical drought thresholds affecting vegetation on the Mongolian Plateau

The increasing frequency of drought events due to global climate change has significant impacts on ecosystems, often resulting in reduced vegetation productivity. However, vegetation responses to drought often exhibit non-linear threshold phenomena, where vegetation growth sharply decreases once water stress reaches a certain level. Our study, conducted on the Mongolian Plateau, focuses on revealing the drought response thresholds and distribution patterns of different vegetation types. These thresholds mark critical turning points from high drought resistance to high vulnerability in vegetation response and serve as early warning indicators, crucial for accurately assessing how terrestrial ecosystems adapt to climate change. We utilized remote sensing observation datasets and inversion datasets spanning from 2001 to 2020, including six representative vegetation indices. The results indicate that: (1) Over 70 % of the Mongolian Plateau experiences low vegetation growth (<10th) predominantly influenced by drought, with low vegetation growth often occurring when water availability falls below the 30th percentile; (2) Areas with higher vegetation coverage and relatively moist climates have lower proportions of drought thresholds, implying that more complex ecosystems can better mitigate water stress, while background climatic conditions also regulate vegetation response to water availability; (3) According to multi-model climate predictions, the overall probability of drought risk on the Mongolian Plateau is projected to significantly increase during 2080–2100, especially in drought-prone regions. These findings provide important insights into better understanding the impacts of drought on ecosystems. Additionally, they emphasize the urgency of taking early measures to adapt to future drought risks.

Mitigation of Drought Stress for Quinoa (Chenopodium quinoa Willd.) Varieties Using Woodchip Biochar-Amended Soil.

Drought stress deteriorates agro-ecosystems and poses a significant threat to crop productivity and food security. Soil amended with biochar has been suggested to mitigate water stress, but there is limited knowledge about how biochar affects the physiology and vegetative growth of quinoa plants under soil water deficits. We grew three quinoa (Chenopodium quinoa Willd.) varieties, Titicaca (V1), Quipu (V2), and UAFQ7 (V3) in sandy loam soil without (B0) and with 2% woodchip biochar (B2) under drought conditions. The drought resulted in significant growth differences between the varieties. V3 performed vegetatively better, producing 46% more leaves, 28% more branches, and 25% more leaf area than the other two varieties. Conversely, V2 displayed significantly higher yield-contributing traits, with 16% increment in panicle length and 50% more subpanicles compared to the other varieties. Woodchip biochar application significantly enhanced the root development (i.e., root biomass, length, surface, and projected area) and plant growth (i.e., plant height, leaf area, and absolute growth rate). Biochar significantly enhanced root growth, especially fresh and dry weights, by 122% and 127%, respectively. However, biochar application may lead to a trade-off between vegetative growth and panicle development under drought stress as shown for V3 grown in soil with woodchip biochar. However, V3B2 produced longer roots and more biomass. Collectively, we suggest exploring the effects of woodchip biochar addition to the soil on the varietal physiological responses such as stomatal regulations and mechanisms behind the increased quinoa yield under water stress conditions.

Use of biostimulants for water stress mitigation in two durum wheat (Triticum durum Desf.) genotypes with different drought tolerance

Agriculture is facing complex and unprecedented challenges, such as climate change and global population growth, associated with the increase of food demand. Durum wheat (DW) is a strategic crop for food security in the Mediterranean region. In this work, the effect of two biostimulant compounds on drought response of two DW genotypes with different drought tolerance degree was evaluated: the tolerant genotype Svems16 and the sensitive cv. Iride. Genotyping-By-Sequencing analysis allowed to identify variants in response to water-related genes, such as those encoding dehydrins, with Svems16 exhibiting a missense variant divergent from the sequence found in Iride. Drought significantly hindered growth of cv. Iride by increasing oxidative stress and diminishing stomata density. This difficulty was mitigated by the application of biostimulants, which induced root morphological changes, and increased stomata density. On the other hand, the growth of Svems16 seedlings was not significantly affected by drought, confirming its significant degree of tolerance toward that stress compared with Iride. As a result, both biostimulants showed limited efficacy when applied to Svems16 stressed plants. In conclusion, the application of biostimulants emerges as a valuable agronomic strategy for mitigating drought stress in sensitive DW cultivars.

Elicitors and Biostimulants to Mitigate Water Stress in Vegetables

Elicitors and Biostimulants to Mitigate Water Stress in Vegetables

O-Carboxymethyl chitosan nanoparticles: A novel approach to enhance water stress tolerance in maize seedlings

Water stress, a significant abiotic stressor, significantly hampers crop growth and yield, posing threat to food security. Despite the promising potential of nanoparticles (NPs) in enhancing plant stress tolerance, the precise mechanisms underlying the alleviation of water stress using O-Carboxymethyl chitosan nanoparticles (O-CMC-NPs) in maize remain elusive. In this study, we synthesized O-CMC-NPs and delved into their capacity to mitigate water stress (waterlogging and drought) in maize seedlings. Structural characterization revealed spherical O-CMC-NPs with a size of approximately 200 nm. These NPs accumulated near the seed embryo and root tip, resulting in a substantial increase in fresh and dry weights. The application of O-CMC-NPs to water-stressed maize seedlings remarkedly elevated the chlorophyll content and activity of various antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and polyphenol oxidase (PPO). The malondialdehyde (MDA) content was significantly reduced compared to the untreated control. Additionally, the expression of stress-responsive genes, such as ZmSOD, ZmCAT, ZmPOD, ZmTIFY, ZmACO, ZmPYL2, ZmNF-YC12, and ZmEREB180, were significantly upregulated in the O-CMC-NPs treated seedlings. These findings unveil the novel role of O-CMC-NPs in enhancing plant stress tolerance, suggesting their potential application in safeguarding maize seedlings under water stress conditions and facilitating the recovery from oxidative damage.

Rice Response to Spermine Foliar Application and Its Association with Aerial Imagery Monitoring Under Water Stress Conditions

Rice is the most consumed food in the world, mainly in Asia and Africa. Malaysia is the second-largest rice importer in Southeast Asia after Indonesia. However, rice yield is limited by water stress. One alternative for a quicker strategy to mitigate water stress is through a combination of foliar spermine application and efficient rice management practices via image monitoring techniques using drone technology. The present study was aimed at evaluating the effects of spermine on rice physiological response and its association with aerial imagery and yield under reproductive during reproductive stage under water stress. The experiment was carried out under greenhouse conditions using a two-factorial randomized complete block design (RCBD), with foliar spermine treatment as the first factor and water stress as the second factor. Physiological parameters showed significantly higher tiller number per pot and photosynthesis rate by 29% and 31%, respectively. Correspondingly, the Normalised Difference Vegetation Index (NDVI) using aerial imagery monitoring showed an increased value in spermine treatments by 2% compared to control. Furthermore, NDVI readings and photosynthetic rate were positively correlated linearly with R2= 0.51. Interestingly, spermine treatments alleviated water stress effects by 40%, 17% and 12% in grain weight per pot, grain number per panicle and percentage filled grain. Biomass partitioning in roots improved by 44% in spermine treatments, even under water stress, due to an efficient translocation of assimilates. In conclusion, spermine foliar application significantly improved growth, grain filling and rice yield production, which was also supported by NDVI values using aerial imagery monitoring.

Sustainable Production of Forage Sorghum for Grain and Silage Production with Moisture-Retaining Polymers That Mitigate Water Stress

Sustainable Production of Forage Sorghum for Grain and Silage Production with Moisture-Retaining Polymers That Mitigate Water Stress

Leaves and roots metabolomic signatures underlying rootstock-mediated water stress tolerance in grafted pepper plants

Grafting onto pepper rootstock NIBER® is an effective strategy to mitigate water stress effects on the grafted variety. In this work, we comparatively explored the metabolomic responses to water stress in the pepper variety “Maestral F1” (V) grafted onto NIBER® (V/N) and self-grafted (V/V) by untargeted metabolomics on leaves and roots. Leaf water status was also evaluated by relative water content (RWC) and gas exchange measurements. Under water stress, the V/N water use efficiency (WUE) and leaf RWC were higher than V/V, in agreement with major stomata closure and water retention in leaves. V/N showed a tolerance response, which was manifested in the untargeted metabolomic analysis. NIBER® modulated the grafted variety response to water stress as reflected in the differential metabolomic profiles in leaves and roots. The V/N-enriched metabolic pathways showed that the NIBER® response to water stress involved cutin and suberin biosynthesis, which act as protection layers, and jasmonic acid (JA) and jasmonates biosynthesis to favor signaling pathways. NIBER® did not induce flavonols and chlorophyll b synthesis, but likely promoted anthocyanins biosynthesis and maintained an undisturbed chlorophyll a:chlorophyll b ratio. Moreover, NIBER® increased vitamin B6, anthocyanins and stearic acid concentration in the variety leaves, whereas siroheme content rose in roots to improve nitrogen assimilation. Further studies are required to understand the contribution of secondary metabolites, such as phenylpropanoids, glycoalkaloids, and nitrogen-containing secondary metabolites, to NIBER® water stress tolerance.

Hydrological and Urban Analysis of Territories under High Water Stress: Nazas and Aguanaval Rivers, Mexico

Hydrological region 36 in Mexico (RH36) faces significant water stress and tends towards agricultural mono-production. Following the regulation of its main rivers, the Nazas and Aguanaval, through dam construction and canalization, the flow of water in the lower basin of the Nazas River has become negligible, which has altered the riverfronts of major cities in the region. Consequently, Torreón, Gómez Palacio, and Lerdo, which are part of the La Laguna Metropolitan Zone (ZML), have expanded into new territories along the riverbanks and adjacent recharge areas. Establishing the boundaries of specific watersheds is crucial for the implementation of targeted rural and urban intervention strategies. This approach enhances understanding of interactions between the natural hydromorphology of a hydrological region, water infrastructure (dams, canals, reservoirs), and the urban and rural landscape. To effectively plan based on watershed boundaries, it is essential to develop hybrid cartographies that integrate urban, architectural, agricultural, and hydrological delineations. These maps provide valuable indicators for watershed-based planning, which facilitates precise hydrological urban restoration strategies tailored to specific basins. This research focuses on developing and presenting such hybrid cartographies, which combine hydrological, rural, and geographic data. This methodology aligns with the overarching objective of mitigating water stress in RH36 and promoting a transition towards more sustainable forms of agriculture.

Application of Plant Growth Regulators Mitigates Water Stress in Basil

Application of Plant Growth Regulators Mitigates Water Stress in Basil

Effect of Arbuscular Mycorrhizal Fungi and Pink Pigmented Facultative Methylotrophs for Mitigating Water Stress in Black Pepper

Effect of Arbuscular Mycorrhizal Fungi and Pink Pigmented Facultative Methylotrophs for Mitigating Water Stress in Black Pepper

A meta-analysis of photosynthetic efficiency and stress mitigation by melatonin in enhancing wheat tolerance

BackgroundOur meta-analysis examines the effects of melatonin on wheat under varying abiotic stress conditions, focusing on photosynthetic parameters, chlorophyll fluorescence, leaf water status, and photosynthetic pigments. We initially collected 177 publications addressing the impact of melatonin on wheat. After meticulous screening, 31 published studies were selected, encompassing 170 observations on photosynthetic parameters, 73 on chlorophyll fluorescence, 65 on leaf water status, 240 on photosynthetic pigments.ResultsThe analysis revealed significant heterogeneity across studies (I² > 99.90%) for the aforementioned parameters and evidence of publication bias, emphasizing the complex interaction between melatonin application and plant physiological responses. Melatonin enhanced the overall response ratio (lnRR) for photosynthetic rates, stomatal conductance, transpiration rates, and fluorescence yields by 20.49, 22.39, 30.96, and 1.09%, respectively, compared to the control (no melatonin). The most notable effects were under controlled environmental conditions. Moreover, melatonin significantly improved leaf water content and reduced water potential, particularly under hydroponic conditions and varied abiotic stresses, highlighting its role in mitigating water stress. The analysis also revealed increases in chlorophyll pigments with soil drenching and foliar spray, and these were considered the effective application methods. Furthermore, melatonin influenced chlorophyll SPAD and intercellular CO2 concentrations, suggesting its capacity to optimize photosynthetic efficiency.ConclusionsThis synthesis of meta-analysis confirms that melatonin significantly enhances wheat’s resilience to abiotic stress by improving photosynthetic parameters, chlorophyll fluorescence, leaf water status, and photosynthetic pigments. Despite observed heterogeneity and publication bias, the consistent beneficial effects of melatonin, particularly under controlled conditions with specific application methods e.g. soil drenching and foliar spray, demonstrate its utility as a plant growth regulator for stress management. These findings encourage focused research and application strategies to maximize the benefits of melatonin in wheat farming, and thus contributing to sustainable agricultural practices.

Do Water Transfer Projects Promote Water Use Efficiency? Case Study of South-to-North Water Transfer Project in Yellow River Basin of China

With a huge capital and labor input influx, inter-basin water transfer (IBWT) projects have been shown to effectively mitigate water stress and ensure the water demand for social and economic development in the receiving area. Whether they have promoted the improvement of regional water use efficiency (WUE) is crucial for sustainable management of regional water resources. Targeting the South-to-North Water Transfer Project (SNWTP), the largest and most ambitious inter-basin water transfer project in China, this study establishes quantitatively econometric models to analyze the impact of different water diversion projects, specifically the eastern route of the SNWTP (ER-SNWTP), middle route of the SNWTP (MR-SNWTP), and diversion from the main stream of the Yellow River (DYR), on the regional water consumption per unit of GDP; regional water stress, water use structure, economic structure, and urbanization level are used as control variables in different types of cities in the Yellow River Basin, and some intriguing results are found. While the overall water transfer project demonstrates a positive impact on water use efficiency, the effects of the three water transfer measures vary significantly. The ER-SNWTP does not exhibit a notable positive effect on regional water use efficiency, whereas the MR-SNWTP demonstrates a significant positive impact. Interestingly, the DYR has a notable negative influence on water use efficiency in developed cities. The water use structure, shaped by the pricing, scale, and policies of different projects, emerges as a pivotal factor in explaining these differences. Finally, this paper suggests that the impact of water transfer projects on the improvement of regional water use efficiency be viewed from a more comprehensive and developmental perspective.

Investigating the synergistic effects of biochar, trans-zeatin riboside, and Azospirillum brasilense on soil improvement and enzymatic activity in water-stressed wheat

BackgroundWater stress is a major danger to crop yield, hence new approaches to strengthen plant resilience must be developed. To lessen the negative effects of water stress on wheat plants, present study was arranged to investigate the role of synergistic effects of biochar, trans-zeatin riboside (t-ZR), and Azospirillum brasilense on soil improvement and enzymatic activity in water-stressed wheat.ResultsIn a three-replication experiment comprising of four treatments (T0: Control, T1: Drought stress (DS), T2: DS + t-ZR with biochar, T3: DS + A. brasilense with biochar), we observed notable improvements in soil quality and enzymatic activities in water-stressed wheat plants with the application of t-ZR and A. brasilense with biochar. In drought stress, Treatment having the application of A. brasilense with biochar performs best as compared to the other and significant increased the enzymatic activities such as peroxidase (7.36%), catalase (8.53%), superoxide dismutase (6.01%), polyphenol oxidase (14.14%), and amylase (16.36%) in wheat plants. Different enzymatic activities showed different trends of results. Soil organic C, dissolved organic C, dissolved organic N also enhanced 29.46%, 8.59%, 22.70% respectively with the application of A. brasilense with biochar under drought stress condition.ConclusionsThe synergistic action of A. brasilense and biochar creates an effective microbiological environment that supports essential plant physiological processes during drought stress. This enhancement is attributed to improved soil fertility and increased organic matter content, highlighting the potential of these novel strategies in mitigating water stress effects and enhancing crop resilience.

A quantile regression approach to assess the impact of water-related environmental innovations on water stress

This paper examines the further question of whether water-related environmental innovations affect water stress in three main sectors such as agriculture, industry and services. The sample consists of 30 OECD countries for the period 2000–2019. This paper employs the method of moments quantile regression (MMQR) with fixed effects to analyze the effects of water-related innovative activities across different quantiles of water stress for all three sectors separately. The empirical results indicate that water-related innovations positively affect water stress in the agricultural sector in the lower and middle quantiles, while it has a negative effect in the middle and higher quantiles for the services sector and the higher quantiles for the industrial sector. These findings reveal nuanced effects of water-related innovations on water stress across sectors. Furthermore, the study suggests that while innovations in the industrial and services sectors can mitigate water stress beyond a certain threshold level, the agricultural sector appears to benefit comparatively less from such innovations. These findings underscore the importance of complementing water-related innovations with appropriate regulatory measures, to address informal practices such as losses and leakages in agricultural irrigation. Ultimately, this study provides valuable insights for policy makers to formulate targeted environmental policies and strategies, especially in the context of climate change adaptation, thereby enabling a more effective allocation of resources to mitigate water stress within each sector.

Microrefugia and microclimate: Unraveling decoupling potential and resistance to heatwaves

Microrefugia, defined as small areas maintaining populations of species outside their range margins during environmental extremes, are increasingly recognized for their role in conserving species in the face of climate change. Understanding their microclimatic dynamics becomes crucial with global warming leading to severe temperature and precipitation changes. This study investigates the phenomenon of short-term climatic decoupling within microrefugia and its implications for plant persistence in the Mediterranean region of southeastern France. We focus on microrefugia's ability to climatically disconnect from macroclimatic trends, examining temperature and Vapor Pressure Deficit (VPD) dynamics in microrefugia, adjacent control plots, and weather stations. Our study encompasses both “normal” conditions and heatwave episodes to explore the role of microrefugia as thermal and moisture insulators during extreme events. Landscape attributes such as relative elevation, solar radiation, distance to streams, and vegetation height are investigated for their contribution to short-term decoupling. Our results demonstrate that microrefugia exhibit notable decoupling from macroclimatic trends. This effect is maintained during heatwaves, underscoring microrefugia's vital role in responding to climatic extremes. Importantly, microrefugia maintain lower VPD levels than their surroundings outside and during heatwaves, potentially mitigating water stress for plants. This study advances our understanding of microclimate dynamics within microrefugia and underscores their ecological importance for plant persistence in a changing climate. As heatwaves become more frequent and severe, our findings provide insights into the role of microrefugia in buffering but also decoupling against extreme climatic events and, more generally, against climate warming. This knowledge emphasizes the need to detect and protect existing microrefugia, as they can be integrated into conservation strategies and climate change adaptation plans.