Water Stress Tolerance Research Articles

Almond Tree Adaptation to Water Stress: Differences in Physiological Performance and Yield Responses among Four Cultivar Grown in Mediterranean Environment.

Maximizing water use efficiency, yield, and plant survival under drought is a relevant research issue for almond-tree-growing areas worldwide. The intraspecific diversity of this species may constitute a valuable resource to address the resilience and productivity challenges that climate change poses to crop sustainability. A comparative evaluation of physiological and productive performance of four almond varieties: 'Arrubia', 'Cossu', 'Texas', and 'Tuono', field-grown in Sardinia, Italy, was performed. A great variability in the plasticity to cope with soil water scarcity and a diverse capacity to adapt to drought and heat stresses during fruit development were highlighted. The two Sardinian varieties, Arrubia and Cossu, showed differences in water stress tolerance, photosynthetic and photochemical activity, and crop yield. 'Arrubia' and 'Texas' showed greater physiological acclimation to water stress while maintaining higher yields, as compared to the self-fertile 'Tuono'. The important role of crop load and specific anatomical traits affecting leaf hydraulic conductance and leaf gas exchanges efficiency (i.e., dominant shoot type, leaf size and roughness) was evidenced. The study highlights the importance of characterizing the relationships among almond cultivar traits that affect plant performance under drought in order to better assist planting choices and orchard irrigation management for given environmental contexts.

Water stress tolerance of several newly derived breadfruit cultivars

To evaluation of several wild wheat and barley genotypes in response to water deficit stress, experiments were laid out in randomized complete block design with three replicates in optimal and stress condition environment for three years. Data analysis showed a significant genetic diversity within genotypes in terms of grain yield, and the existence of significant genotype × environment interaction, made it possible to analyze data for genotypes stability to environment in this study. The stability analysis showed that Garni (an emmer variety) was recognized as the most stable genotype to water deficit stress with a high grain yield. The stress tolerance tests also found that the Garni genotype is more tolerant to water deficit stress than other genotypes. Based on the results obtained, Garni genotype was recognized as a stable genotype and the most tolerant genotype to water deficit stress that has a high grain yield, and it can be used as a crossbreeding parent in wheat breeding.

Functional phenotypic plasticity mediated by water stress and [CO2] explains differences in drought tolerance of two phylogenetically close conifers.

Forests are threatened globally by increased recurrence and intensity of hot droughts. Functionally close coexisting species may exhibit differences in drought vulnerability large enough to cause niche differentiation and affect forest dynamics. The effect of rising atmospheric [CO2], which could partly alleviate the negative effects of drought, may also differ between species. We analysed functional plasticity in seedlings of two taxonomically close pine species (Pinus pinaster Ait., Pinus pinea L.) under different [CO2] and water stress levels. The multidimensional functional trait variability was more influenced by water stress (preferentially xylem traits) and [CO2] (mostly leaf traits) than by differences between species. However, we observed differences between species in the strategies followed to coordinate their hydraulic and structural traits under stress. Leaf 13C discrimination decreased with water stress and increased under elevated [CO2]. Under water stress both species increased their sapwood area to leaf area ratios, tracheid density and xylem cavitation, whereas they reduced tracheid lumen area and xylem conductivity. Pinus pinea was more anisohydric than P. pinaster. Pinus pinaster produced larger conduits under well-watered conditions than P. pinea. Pinus pinea was more tolerant to water stress and more resistant to xylem cavitation under low water potentials. The higher xylem plasticity in P. pinea, particularly in tracheid lumen area, expressed a higher capacity of acclimation to water stress than P. pinaster. In contrast, P. pinaster coped with water stress comparatively more by increasing plasticity of leaf hydraulic traits. Despite the small differences observed in the functional response to water stress and drought tolerance between species, these interspecific differences agreed with ongoing substitution of P. pinaster by P. pinea in forests where both species co-occur. Increased [CO2] had little effect on the species-specific relative performance. Thus, a competitive advantage under moderate water stress of P. pinea compared with P. pinaster is expected to continue in the future.

Impact of Water Deficit and Salinity Stress on the Growth and Development of Oenothera biennis L.

The present study aimed at determining the morphological response of Oenothera biennis L. under water stress and salinity stress. Water deficit and salinity stress are one of the major abiotic stress factors show negative impact on growth, development and yield on different agricultural activities. Thus demands the need of developing water deficit and salt tolerant plant varieties. Oenothera biennis L. is one of the important medicinal plant with several medicinal properties, but information related to morphological response which helps in determining the level of water and salinity stress tolerance in Oenothera biennis L. has not been reported yet. So, the present study is carried out to investigate the effect of water stress and salinity stress under different concentrations i.e. water stress (-0.01 M Pa, -0.03 M Pa, -0.05 M Pa and -0.07 M Pa) and salinity stress (25 mM, 50 mM, 75 mM and 100 mM NaCl) on shoot length, no. of leaves, no. of flowers, no. of nodes, seed yield and root length. At lower water and salinity stress concentrations the Oenothera biennis L. has shown tolerance in terms of morphological features. In overall, Oenothera biennis L. is tolerant to mild water stress and salinity stress.

Genome-Wide Association Study of Agronomic and Physiological Traits Related to Drought Tolerance in Potato

Potato (Solanum tuberosum L.) is often considered a water-sensitive crop and its production can be threatened by drought events, making water stress tolerance a trait of increasing interest. In this study, a panel of 144 tetraploid potato genotypes was evaluated for two consecutive years (2019 and 2020) to observe the variation of several physiological traits such as chlorophyll content and fluorescence, stomatal conductance, NDVI, and leaf area and circumference. In addition, agronomic parameters such as yield, tuber fresh weight, tuber number, starch content, dry matter and reducing sugars were determined. GGP V3 Potato array was used to genotype the population, obtaining a total of 18,259 high-quality SNP markers. Marker-trait association was performed using GWASpoly package in R software and Q + K linear mixed models were considered. This approach allowed us to identify eighteen SNP markers significantly associated with the studied traits in both treatments and years, which were related to genes with known functions. Markers related to chlorophyll content and number of tubers under control and stress conditions, and related to stomatal conductance, NDVI, yield and reducing sugar content under water stress, were identified. Although these markers were distributed throughout the genome, the SNPs associated with the traits under control conditions were found mainly on chromosome 11, while under stress conditions they were detected on chromosome 4. These results contribute to the knowledge of the mechanisms of potato tolerance to water stress and are useful for future marker-assisted selection programs.

Comparative study of standard heterosis for yield and its attributes in bread wheat under two different water regimes

AbstractWater stress conditions have occurred in the past in various places of the world, affecting the yield and production of numerous crops, including wheat. The aim of this research was to estimate standard heterosis under two different water regimes for grain yield and its attributes in 33 crosses, which were obtained by crossing 11 lines and 3 testers in a Line × Tester mating design. The best cross combinations for yield and contributing traits under irrigated condition were C4, C8, C33, C24, and C23, compared to both checks HD2967 and PBW660. Whereas, in rainfed condition, C18, C14, C26, C21, and C20 crosses were superior to the checks. For both irrigated and rainfed conditions, the best cross combinations identified were C29, C15, C32, C2, and C31. As a result, these cross combinations could be used in wheat breeding programmes to improve bread wheat genotypes for increased grain yield, agro-morphological features, and water stress tolerance. The presence of high heterosis for yield-contributing traits not only aids in the development of hybrids by exploiting heterosis but also in the production of transgressive segregants to develop elite lines.

Exogenous Application of Salicylic Acid Improves Physiological and Biochemical Attributes of Morus alba Saplings under Soil Water Deficit

Morus alba L. is a multipurpose and fast-growing tree species. However, its growth and productivity are susceptible to water stress. Therefore, a study was conducted to check the effectiveness of foliar application of salicylic acid (SA) in improving the water stress tolerance of M. alba. A pot experiment was conducted and the morphological, physiological and biochemical attributes of young M. alba saplings were assessed under control (CK, 90% of field capacity (FC)), moderate (MS, 60% of FC) and high soil water deficits (HS, 30% of FC), along with MS and HS + foliar application of SA 0.5 and 1.0 mM (MS + 0.5; HS + 0.5; MS + 1.0, and HS+1.0, respectively). Results demonstrated that the highest decrease in plant growth, leaf, stems and roots’ dry biomass, chlorophyll a, b, carotenoid contents and leaf gas exchange parameters was observed under HS, whereas the lowest decrease was evidenced for HS + 1.0 mM SA. Electrolyte leakage, malondialdehyde contents, hydrogen peroxide and superoxide radicals significantly increased under HS, while the lowest increase was evidenced for HS + 1.0 mM SA. The highest increase in proline content, total soluble sugar, total phenolic content, soluble protein and superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase was also found under HS + 1.0 mM SA. Based on the results, it can be concluded that foliar application of SA can help improve the water deficit tolerance of Morus alba saplings, especially under high soil water deficit.

Effects of Polyploidy on Physiological Performance of Acclimatized Solanum betaceum Cav. Plants under Water Deficit

The urgent need to identify stress-tolerant genotypes and understand their inherent genetic plasticity is one of the major targets of research and breeding programs. Species that are cultivated in areas that are prone to drought need to be able to tolerate water stress (WS) while still displaying features that are economically valuable. Tamarillo (Solanum betaceum) is a solanaceous fruit crop with increasing agronomic interest due to the nutritional properties of its edible fruits and its biotechnological potential. Several protocols have been established for the in vitro culture of this species and controlled hybridization, as well as for the induction of tetraploidy. Nevertheless, the impact of WS on S. betaceum performance has been poorly studied, and nothing is known about the role of ploidy status on this response. Since no morphological differences were noticed between diploids and tetraploids at the end of the acclimatization period, we hypothesized that ploidy level may have a role in plant drought responses. Thus, micropropagated and acclimatized tamarillo diploid (2n = 2x = 24) and tetraploid (4n = 4x = 48) plants were exposed to WS, and several physiological parameters were evaluated, such as plant growth, water potential, photosynthetic performance, sugars, proline, and MDA levels. Water stress did not affect plant growth in both diploids and tetraploids, but it induced stomatal closure and reduced the net CO2 assimilation rate. Water stress also reduced the photosynthetic efficiency of PSII, but no differences were found in the total chlorophyll content. From all the parameters analyzed, tetraploid plants showed a better response under water shortage conditions when considering water potential (WP). Metabolite analysis indicated no significant differences in the accumulation of soluble sugars and MDA in WS plants but a significant increase in proline accumulation in diploids exposed to WS. These observed differences in parameters such as WP and proline accumulation point to mechanisms of osmoregulation and stress signaling that differ between diploid and tetraploid plants, particularly in WS conditions, demonstrating that tetraploids can adapt better to water shortage conditions than their diploid counterparts.

Bin mapping of water stress tolerance‐related, fruit quality, and horticultural traits in tomato introgression lines derived from wild Solanum habrochaites

AbstractClimate change is reducing water availability for crop production. Cultivated tomato, Solanum lycopersicum, has a limited genetic base for improvement. A wild tomato, Solanum habrochaites, is water stress tolerant and may serve as a genetic source of abiotic stress‐tolerance traits. A set of 24 introgression lines (ILs) derived from S. habrochaites and processing tomato inbred cultivar E6203 were evaluated in the field in replicated experiments over 3 years for 15 traits, including water stress tolerance‐related, fruit quality, and horticultural traits. A split plot experimental design was employed with reduced and full irrigation treatments as main plots. Subplots consisted of the ILs and control E6203, and trait data were collected on a per‐subplot basis. Statistical data analyses and bin mapping were performed on a per‐trait basis. Trait‐genomic region associations (TGRAs) were detected in ILs when a significant difference between E6203 and an IL was present. A total of 268 TGRAs were detected for all 15 traits. Traits mapped to introgressions in 22 of the 24 ILs and in 11 of 12 tomato chromosomes. ILs contributed both positive and negative allelic effects at TGRAs. TGRA with positive allelic effects from S. habrochaites were identified for soluble solids content, fruit weight, degree of fruit sunburn, canopy cover, and maturity. Our results suggest that S. habrochaites may be a useful resource for breeding improvement of certain fruit quality and horticultural traits in cultivated tomato. Overall, S. habrochaites alleles did not contribute to increased water stress tolerance relative to E6203 at the milder level of water stress used in this study.

Abundance, diversity, and composition of root-associated microbial communities varied with tall fescue cultivars under water deficit.

The plant breeding program has developed many cultivars of tall fescue (Festuca arundinacea) with low maintenance and stress tolerance. While the root-associated microbial community helps confer stress tolerance in the host plant, it is still largely unknown how the microbiota varies with plant cultivars under water stress. The study aimed to characterize drought-responsive bacteria and fungi in the roots and rhizosphere of different tall fescue cultivars. Intact grass-soil cores were collected from six cultivars grown in a field trial under no-irrigation for 3 years. Tall fescue under irrigation was also sampled from an adjacent area as the contrast. Bacterial and fungal communities in roots, rhizosphere, and bulk soil were examined for abundance, diversity, and composition using quantitative-PCR and high-throughput amplicon sequencing of 16S rRNA gene and ITS regions, respectively. Differences in microbial community composition and structure between non-irrigated and irrigated samples were statistically significant in all three microhabitats. No-irrigation enriched Actinobacteria in all three microhabitats, but mainly enriched Basidiomycota in the root endosphere and only Glomeromycota in bulk soil. Tall fescue cultivars slightly yet significantly modified endophytic microbial communities. Cultivars showing better adaptability to drought encompassed more relatively abundant Actinobacteria, Basidiomycota, or Glomeromycota in roots and the rhizosphere. PICRUSt2-based predictions revealed that the relative abundance of functional genes in roots related to phytohormones, antioxidant enzymes, and nutrient acquisition was enhanced under no-irrigation. Significant associations between Streptomyces and putative drought-ameliorating genes underscore possible mechanics for microbes to confer tall fescue with water stress tolerance. This work sheds important insight into the potential use of endophytic microbes for screening drought-adaptive genotypes and cultivars.

Seasonal temperature and precipitation regimes drive variation in the wood of oak species (Quercus) along a climatic gradient in western Mexico

Summary To achieve optimal balance among wood’s support, storage, and transport functions, tree species present adaptive variation in wood anatomical traits. Oaks (Quercus) are woody plants that are dominant in many ecosystems, possess wide variation in wood traits, and can tolerate water stress in diverse habitats. Mountain regions contain steep climatic gradients that exert strong environmental pressures on wood traits. The aims of this study were: (1) to quantify the anatomical variation in 21 oak species distributed along an environmental gradient and (2) to analyze the interspecific variation among the studied species. Fibres and parenchyma fractions were the most abundant cell types. We found a trade-off between total fibre fraction and total parenchyma fraction modulated by the precipitation during the warmest quarter in which oak species in drier areas invested more in support cells. The 21 oak species studied showed vasicentric tracheids, which could be essential to compensate for the transport system in drier areas. Wood density was negatively correlated with the axial parenchyma fraction and fibre lumen width. Oak species have high interspecific variation in the total vessel fraction and vessel diameter. Anatomical variation in oak species along a climatic gradient showed a broad continuum of fibre characteristics from wide to narrow wall and lumen, abundant to scarce parenchyma, and wide to narrow vessels. These variations imply a diversification of ecological strategies within the genus that includes the vascular design of the stem to define the tolerance and competitiveness of the oak species.

Bibliometric Analysis of Peer-Reviewed Literature on Stress Factors Affecting Agricultural Productivity

Sustaining agricultural productivity is essential to ensuring food security. Climate change, increasing population and dwindling resources are factors of concern threatening crop productivity. Research across the globe have focused on seeking innovative measures to protect and enhance crop yield. We explored and analyzed peer-reviewed literature to provide an understanding of current and emerging trends in the field. A bibliometric method was followed using the database Scopus. Search queries used to retrieve documents were “Agriculture/crop productivity” and “Plant stress”. The study period was restricted to the last five years, from 2017-2021. The search query found 2207 documents in Scopus under the agriculture and plant stress theme. Increasing growth of publications was observed in successive years. Research activities in this field have the most contributors from Asian countries – China and India followed by the US. The major stresses affecting agricultural productivity being investigated were-Water stress, Temperature stress, Salinity stress. Amongst these, the theme related to water stress/ precipitation/ drought stress was the most investigated. The availability of water has a pivotal role in sustainable agriculture. The use of conservation agricultural practices such as intercropping, no-tillage, and soil mulching has proven to be effective in retaining soil water content and reducing the dependency on irrigation, especially in rainfed areas, thereby assisting in drought mitigation and increasing crop yield. Precision agriculture approach employing satellite data to predict weather and rainfall and early detection of stress signals using hyperspectral reflectance has shown promising results in ensuring sustained productivity. Breeding and transgenic approaches for plants with higher water use efficiency (WUE) and the ability to tolerate water stress are key areas of research being followed throughout the world.

MINING OF 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID DEAMINASE EXHIBITING WATER STRESS TOLERANT NOVEL RHIZOBACTERIAL ISOLATES

An investigation was carried out to isolate, characterize and identify the rhizobacterial isolates of crop plants grown in the arid region of the North-eastern Karnataka.Twenty-one strains out of 120 rhizobacterial isolates that grew vigorously at-0.30Mpa were selected, and strains were biochemically characterized and screened in vitro to determine their water stress tolerance activity. Among 21 isolates, APPP-1 and GPPP-1 showed ACC deaminase activity (5.13 µMmg-1/h and 2.69µMmg-1/h, respectively). The isolate BSOP-1 produced higher proline (138.87µMmg-1) and IAA (68.49 µg ml-1); while NONB-2 produced higher exopolysaccharides (23.53mg mg-1 protein) at-0.30Mpa. Our study recorded the ACC Deaminase activity of the isolates, APPP-1and GPPP-1 later identified as a novel strain of Pseudomonas sp. VG309(NCBI accession number MH664930) and Corynebacterium kroppenstedtii (NCBI accession number MH671918) through 16SrDNA molecular sequencing technique

Genotypic Characterization of Cotton (Gossypium hirsutum L.) for Physiological Attributes Associated with Water Stress Tolerance

Drought has an impact on agricultural growth and development, which significantly reduces output and degrades produce quality. Fifty cotton genotypes were tested in the field for performance under artificially produced water deficit stress conditions. In 2015, sowing was carried out in the first week of May with two sets of every genotype in each replication. While the other set continued to be stressed by a water shortage, one set was regularly irrigated. The crop was allowed to grow for a duration of four weeks. Data on various physiological markers related to different genotypes' resistance to water stress were gathered. The findings showed that under normal and stressful conditions, the genotypes differed significantly (p 0.01) in a number of physiological variables e.g. relative water content, cell damage, leaf water potential, excised leaf water loss, osmotic potential, and stomatal conductance. For the several variables examined, very significant interactions (p0.01) were also found between genotypes and water stress. The genotypes include (Include nut shell results indicating susceptible and tolerant varieties)

AN OVERVEW OF BREEDING FOR DROUGHT STRESS TOLERANCE IN COTTON

Drought is a main non-living factor that causes severe crop yield loss globally. Given the strengthening and reappearance of drought events and their impacts, it's important to deepen our understanding as a key to subsidizing mechanisms for drought training and mitigation plans. Pakistan is ranked maximum of the top 5 biggest cotton manufacturers, the seventh largest material producer international, and cotton contributes 10% to the country-wide GDP compared to the overall agriculture area GDP percentage of 18.9%. Cotton farming performs a tremendous role in presenting direct livelihood to 11 million farmers. The cotton crop, in particular, is confined to northern, imperative, and southern zones, with approximately 90 in keeping with cent of the area coming beneath 3 zones. Regardless of this, its cumulative, not apparent impact and multidimensional nature significantly impact the cotton plant’s morphological, physiological, biochemical, and molecular attributes with a detrimental impact on photosynthetic capability. Dealing with water scarcity, plants evolve various complicated resistance and edition mechanisms, including physiological and biochemical responses, which range with species stage. The sophisticated adaptation mechanisms and regularity community that improve the water stress tolerance and version in plants are briefly discussed. Growth pattern and structural dynamics, reduction in transpiration loss via altering stomatal conductance and distribution, leaf rolling, root-to-shoot ratio dynamics, root duration increment, accumulation of like-minded solutes, enhancement in transpiration performance, osmotic and hormonal regulation, and behind-schedule senescence are the techniques that are followed using cotton plant life underneath water deficit. Approaches for drought stress resistance we develop transgenic cotton plants which which can tolerate drought stress to improve cotton quality with good yield.

Agronomic and physio-biochemical responses of lettuce to exogenous sodium nitroprusside (SNP) applied under different irrigation regimes

Drought adversely affects crop production in areas with water shortages. In such areas, various methods need to be implemented to alleviate the effect of water stress on plants. Nitric oxide (NO) is an important plant growth regulator that affects various physiological processes. In this study, we determined ways to increase water-stress tolerance of lettuce by applying exogenous sodium nitroprusside (SNP, a donor of NO). In total, 12 treatments were administered, including three SNP doses (0, 50, and 100 µM) and four levels of irrigation (I100, I80, I60, and I40). An increase in the doses of NO partially increased the water consumption of lettuce under full and deficit irrigation conditions. The highest water consumption (125.1 mm) and the highest yield (39.1 t/ha) were recorded for lettuce plants that were administered the I100 treatment with 100 µM SNP. SNP significantly increased the lettuce yield and irrigation water productivity (IWP) under deficit irrigation and full irrigation. SNP promoted chlorophyll synthesis by increasing photosynthesis. The application of 100 µM SNP increased catalase (CAT) activity approximately three times compared to CAT activity in the control group, and it also significantly increased peroxidase (POD) activity. Additionally, high doses of SNP reduced membrane damage in lettuce leaves. These results indicated that under water stress, exogenous NO improves photosynthesis by increasing chlorophyll synthesis, activates antioxidant enzymes, such as CAT and POD, protects lettuce against oxidative damage, and increases irrigation water productivity, thus increasing the yield.

Comprehensive Selection Criteria for Some Barley Genotypes under Different Water Stress Treatments

Nowadays, water scarcity is a great danger to agriculture development, in semiarid and arid regions beside climate change risks. Egypt is suffering from scarce water resources for agriculture; it is of high priority to rationalize irrigation water use. During two seasons, 2019/2020 and 2020/2021 the experimental were carried out to investigate the effect of three different irrigation water treatments (I1 at 45, I2 at 60 and I3 at 75% depletion of available soil moisture) on some photosynthetic, agronomical, grain quality parameters, water productivity for eight barley genotypes. Also, classify them on the SSR molecular level. The results showed that there were high genetic variations found among the eight genotypes with significant responses to irrigation water treatments. Rationalize irrigation water from I1 to I3 had a negative effect on all studied phenotypic traits, whereas had an appositive effect on leaf diffusive resistance and cured protein content and inducement all genotypes to flower early by average increasing (27.7, 12.7 and 7.08%) respectively. Giza 138, Giza 131, and Line 4 gave high mean performance values of the measured characters besides, attaining high WP values were 1.14, 1.08, and 0.89 kg grain/m3 applied water I1, I2, and I3 irrigation treatments, respectively. While, WUE values increased with increasing water availability. Water use efficiency values were 1.92, 1.71, and 1.34 kg grain/m3 consumed water for I1, I2, and I3 irrigation treatments, respectively. Twenty-six alleles were generated using ten SSR primers with a mean value of 2.6 alleles per locus. The Polymorphism Information Content (PIC) value of each SSRs marker ranged from 0.33 (Bmag 0387) to 0.47 (Bmac 0167) with an average value of 0.34. Cluster analysis clustered the eight barley genotypes into two major clusters divided according to their response to water stress tolerance. The genetic information about eight barley genotypes for water stress tolerance was established, for use them in breeding programs in Egypt.

Sustainable Agricultural Intensification and Climate Smart Agricultural Practices for Improved Food and Climate Security

The grand challenge of increasing production and access to nutritious and safe food to meet growing populations under threat to climate change and climate variability requires systems and transdisciplinary approaches towards agri-food systems. Sustainable agricultural intensification (SAI) focuses on increasing agricultural production from existing farmland without any adverse environmental impacts. There are three major components of SAI which include: (i) genetic intensification (e.g., focused on improving yields, resistance to pests and diseases, tolerance to abiotic stresses, increasing nutritional quality of food products, and using precision breeding, genetics, and genomics tools); (ii) ecological intensification (e.g., focused increasing diversification, farming, cropping and agroforestry systems, resource use efficiency, integrated water, nutrient and pest management); and (iii) socio-economic intensification (e.g., focused on markets, value addition, income generation, policy, creating enabling environment, and building social capital). Climate-smart agricultural (CSA) practices emphasize greenhouse gas emissions, water footprint, and focus on both adaptation and mitigation strategies. Few selected SAI and CSA practices include minimum and no-tillage; cover crops; crop diversity and genotypes selection for effective water use and stress tolerance; diversification (crop mixtures and rotations; perennials, agroforestry systems; forage crops; dual purpose crops); and nutrient recycling from livestock. Overall, developing adoption and scaling of these practices will require convergence of biophysical and social sciences, participatory approaches, public and private sector engagement and commitment of resources from all donor agencies for research and development, human and institutional capacity building.

Accelerated growth rates of Norway spruce and European beech saplings from Europe's temperate primary forests are related to warmer conditions

Global change outcomes for forests will be strongly influenced by the demography of juvenile trees. We used data from an extensive network of forest inventory plots in Europe to quantify relationships between climate factors and growth rates in sapling trees for two ecologically dominant species, Norway spruce and European beech. We fitted nonlinear regression models with annual radial growth measurements from ∼17,500 trees in primary forests to investigate the sensitivity of individuals to temperature and measures of water supply. We controlled for multiple, potentially confounding factors, including ontogeny, resource competition and the deposition of anthropogenic nitrogen and sulphur. The growth potential of spruce was markedly elevated relative to beech, reflecting species-specific relationships with environmental drivers. Declining water availability more strongly limited productivity in spruce, while beech was notably tolerant of observed levels of moisture limitation. Warming promoted growth in both species, but growing season temperatures that exceeded thermally optimum conditions constrained wood production. We identified long-term positive trends in reconstructed annual rates of juvenile tree growth since the early 19th century, likely driven by industrial-era warming. However, our findings suggest that sustained warming and more prevalent future drought may ultimately inhibit growth due to thermal thresholds and a differential tolerance of water stress. Consequently, global change factors may be expected to affect future species abundance patterns, biomass production, and the carbon sink capacity of forests in Europe.

Exogenous treatment with melatonin enhances waterlogging tolerance of kiwifruit plants.

Waterlogging stress has an enormous negative impact on the kiwifruit yield and quality. The protective role of exogenous melatonin on water stress has been widely studied, especially in drought stress. However, the research on melatonin-induced waterlogging tolerance is scarce. Here, we found that treatment with exogenous melatonin could effectively alleviate the damage on kiwifruit plants in response to waterlogging treatment. This was accompanied by higher antioxidant activity and lower ROS accumulation in kiwifruit roots during stress period. The detection of changes in amino acid levels of kiwifruit roots during waterlogging stress showed a possible interaction between melatonin and amino acid metabolism, which promoted the tolerance of kiwifruit plants to waterlogging. The higher levels of GABA and Pro in the roots of melatonin-treated kiwifruit plants partly contributed to their improved waterlogging tolerance. In addition, some plant hormones were also involved in the melatonin-mediated waterlogging tolerance, such as the enhancement of ACC accumulation. This study discussed the melatonin-mediated water stress tolerance of plants from the perspective of amino acid metabolism for the first time.