Water Availability Conditions Research Articles

Early development of Acacia longifolia is more severely impacted by water and nutrient stress in invasive than native seedlings

AbstractAcacia longifolia (Andrews) Willd. is a legume native to southeast mainland Australia and Tasmania and has two described subspecies: A. l. subsp. longifolia and A. l. subsp. sophorae. The species has been introduced around the world and is considered invasive in several Mediterranean-type climate regions, including in South America, South Africa, and southern Europe. Previous studies comparing native and invasive populations of A. longifolia have focused on its reproductive ecology and population genetics, and little information exists on the species’ early life development and how abiotic factors influence it. Here, we performed a glasshouse experiment to compare the phenotypic responses of native and invasive (in Portugal) A. longifolia seedlings to different levels of water and nutrient availability. We found that seedlings of both subspecies responded similarly to different water and nutrient availability conditions in terms of biomass accumulation, root length, the number of phyllodes produced, phyllode water content, and root-to-shoot ratio. However, compared to native seedlings, invasive seedlings had limited capacity for stress responses. We found that invasive seedlings had lower drought tolerance than native seedlings, and thus the speed of invasion by A. longifolia into drier parts of Portugal may be hindered. Our results also hint of a possible role of seed “imprinting” in this species’ early growth responses, resulting in different resource allocation strategies such as favouring early growth and development over drought resistance in the invaded range. Further studies are required to better understand the species’ abiotic stress responses at the intraspecific level and their relation to its invasiveness.

Trichoderma harzianum enhances root biomass production and promotes lateral root growth of soybean and common bean under drought stress

AbstractDrought stress (DS) is one of the main environmental stresses that determines crop productivity. It has been estimated that DS depresses over 40%–60% of soybean (Glycine max (L.) Merr.) and common bean (Phaseolus vulgaris L.) production worldwide, respectively. Although different agronomic strategies are sometimes implemented, the current goal in sustainable agriculture could involve the inoculation with native microorganisms to mitigate DS effects. A potential fungal candidate is Trichoderma, which is recognized as a ubiquitous soil inhabitant with growth‐promoting and biocontrol potentiality. However, its potential for mitigating the stress for water deficit is less well‐documented. Our objective was to evaluate the effect of inoculation with native Trichoderma harzianum strains on soybean and common bean growth under contrasting conditions of water availability. Seeds were independently inoculated (or not) with IB‐J15 and IB‐363 strains, and plants were submitted to DS or were kept under optimal irrigation (well‐watered, WW). In both legumes, the most evident effect after being inoculated was the modification of plant root architecture, the increase in root area and the development of lateral roots in plants under WW and DS conditions. In soybean, both Trichoderma strains had a positive inoculation response, both fresh and dry root biomass increased under WW, and remarkably under DS conditions. The main effect was an increase of about 110% in root dry weight under WW and, about 330% in DS in plants inoculated with IB‐J15 strain, meanwhile, plants inoculated with IB‐363 increased root dry weight 60% in WW and 177% in DS conditions. Notably in soybean, the inoculation with both Trichoderma strains increased the root area more than 70% in both WW and DS conditions. Common beans inoculated with IB‐363 under WW conditions, reached a positive inoculation responsiveness of around 247% in shoot dry weight biomass, and under WW both strains increased the root area more than 50%. Further, IB‐363 increased leaf area by 25% in WW and 72% in DS. Additionally, the in vitro co‐culture between both Trichoderma strains and nodulating Rhizobium etli and Bradyrhizobium japonicum E109 showed compatibility between microorganisms, since no inhibition of their growth was observed. We emphasize that plants inoculated with Trichoderma showed better resistance to water deficit, as seen by redistribution of photosynthates, prioritizing mainly, the development of the root system. © 2024 Association of Applied Biologists.

IMPACTS OF WATER STRESS ON Urochloa brizantha FORAGE CULTIVARS

Water deficit during the dry season is one of the main factors affecting the productivity and quality of pastures. The present work aims at evaluating the effects of water deficit on the morphological and productive characteristics of Urochloa brizantha cultivars grown in Quartzarenic Neosol. The experiment was conducted in a greenhouse under a completely randomized design with a 4×2 factorial arrangement, with four cultivars (Marandu, MG4, MG13 Braúna and MG5 Vitória), two water availability conditions (50% or 100% of field capacity) and six repetitions. Structural, morphogenic and productive variables were evaluated 15, 25 and 35 days after the beginning of treatment application. For all productive characteristics evaluated during 35 days of water stress, it was observed that a 50% reduction in water availability significantly (P<0.05) reduced total fresh and dry mass production and leaf production of Marandu, MG13 Braúna and MG5 Vitória. Except for MG13 Braúna, the leaf/stem ratio of these cultivars was impaired. Regardless of water availability, when comparing forages during 35 days, lower cumulative leaf length and higher fresh and dry mass production of stems were observed in the Marandu cultivar. Regarding the response of productive characteristics, the MG4 cultivar showed the best results under water deficit when grown in Quartzarenic Neosol.

Ácido salicílico induz aclimatação ao déficit hídrico em genótipos de Phaseolus lunatus

ABSTRACT In Brazil, the lima bean is the second most economically significant legume within the genus Phaseolus. Climate change, particularly water scarcity, threatens the production of this species. The application of salicylic acid has mitigated the adverse effects of stress. This study aimed to assess the impact of salicylic acid on acclimatisation to water restriction in three genotypes of Phaseolus lunatus (‘Cara Larga’, ‘Cearense’, and ‘Orelha de Vó’). A completely randomised design with a triple factorial included three broad bean genotypes, two pre-conditionings with 1.0 mM salicylic acid and without this elicitor (0.0 mM), and three levels of water availability (75, 50, and 25%), totalling 18 treatments with eight replicates. Physiological and biochemical responses were evaluated after 60 days of treatment. The responses varied among the genotypes. ‘Cara Larga’ stood out regarding osmoregulatory and antioxidant parameters compared to the other genotypes. In contrast, ‘Cearense’ showed an increase only in carbohydrates and carotenoids concentrations, while ‘Orelha de Vó’ exhibited more efficient water use and higher levels of proline under greater water restriction, concurrently with a decline in other parameters. Overall, the ‘Cara Larga’ genotype appears to be the most responsive to the modulating effects induced by acid application, especially under a water restriction of 25%. Applying, applying salicylic acid under conditions of low water availability may be a strategy for modulating the synthesis of osmoregulatory and antioxidant responses in P. lunatus.

Genetic Potential of Newly Developed Maize Hybrids under Different Water-Availability Conditions in an Arid Environment.

Drought is a crucial environmental stress that tremendously impacts maize production, particularly under abrupt climate changes. Consequently, breeding drought-tolerant and high-yielding maize hybrids has become decisive in sustaining its production and ensuring global food security under the global fast-growing population. The present study aimed to explore drought tolerance and agronomic performance of newly developed maize inbred lines and their hybrids. Ten newly developed maize inbred lines were crossed with two high-yielding testers using a line × tester mating design. The developed twenty hybrids alongside two high-yielding commercial hybrids were evaluated under water-deficit (5411 m3/ha) and well-watered (7990 m3/ha) conditions in dry summer climate conditions. Highly significant variations were detected among the evaluated hybrids for all studied agronomic traits under well-watered and water-deficit conditions. The inbred lines L10 and L6 were particularly notable, demonstrating the most significant negative general combining ability (GCA) effects for earliness, which is crucial for stress avoidance in both environmental settings. Inbred lines L11, L7, L6, and L1 also showed the highest positive and most significant GCA effects for key yield traits, indicating their potential as parents in breeding programs. The crosses L-10×T-1 and L-6×T-2 were outstanding for their heterotic effects on earliness in days to tasseling and silking. Similarly, the crosses L-4×T-2 and L-1×T-1 excelled in plant and ear heights under both irrigation regimes. The hybrids L-1×T-2 and L-7×T-1 demonstrated superior heterosis for chlorophyll content, number of rows per ear, and overall grain yield. Additionally, hybrids L-11×T-1 and L-11×T-2 exhibited remarkable heterotic effects for the number of grains per row, number of rows per ear, 100-kernel weight, and grain yield, highlighting their potential in breeding for productivity. Based on drought tolerance indices and cluster analysis, the cross combinations L-11×T-1, L-11×T-2, L-7×T-1, and L-1×T-2 were classified as the most drought-tolerant crosses. The principal component analysis highlighted traits such as days to tasseling, days to silking, chlorophyll content, plant height, ear height, number of grains per row, number of rows per ear, and 100-kernel weight can be taken as selection criteria for improving grain yield in maize breeding programs under limited water conditions. Based on the summarized results, the identified genetic materials could be considered promising under both conditions and hold potential for future breeding programs.

POTENSI KETERSEDIAAN AIR DAS LOGAWA DENGAN MEMPERHITUNGKAN PERUBAHAN IKLIM

Water is one of the non-biological natural resources which can be renewed through the hydrological cycle. As the human population increases and the phenomenon of climate change, the availability of water tends to decrease both in terms of space, time, quality and quantity resulting in an imbalance between demand and availability. In addition to the increase in human population, climate change and the distribution of rain that is not always evenly distributed, the availability of groundwater is always different at any given time and place. The Logawa sub- watershed is one of the most influential watersheds in Banyumas Regency. Therefore, an analysis is needed regarding the impact of changes in rainfall on the condition of water availability in this watershed. One of the analyzes that can be done is to use the HEC-HMS software and a scenario neutral approach. The aims of this study were (i) to know the parameters of the Logawa watershed using the HEC-HMS model; (ii) Applying the HEC-HMS software to determine water availability in the Logawa watershed; (iii) Knowing the HEC-HMS model calibration process); and (iv) know how to calculate climate change using a scenario-neutral approach. The research method used is quantitative using secondary data. The data used are watershed geospatial data and watershed biogeophysical characteristics data. The HEC-HMS simulation method used is the User Hyetograph Model, Soil Moisture Accounting, Clark's Unit Hydrograph, Recession Baseflow. The results are (i) a hydrological model with a PBIAS value of -2.474% and an NSE of 0.153 is obtained; (ii) results of 130 rainfall scenarios; and (iii) reliable debit from the GPCC satellite rain data input and scenario-neutral approach rainfall data.

Wood Basic Density Assessment of Eucalyptus Genotypes Growing under Contrasting Water Availability Conditions

Limited research exists on wood properties in E. nitens × E. globulus hybrid genotypes grown in water-limited conditions generated by the climate change influence in Mediterranean areas. The EUCAHYDRO project aimed to assess environmental stress impacts on eucalyptus genotypes, including responses to reduced water availability, and to evaluate wood density and resistance using the non-destructive drill resistance technique. This study focused on 10-year-old E. nitens × E. globulus hybrids and Eucalyptus badjensis Beuzev. & Welch, revealing that low irrigation led to a 13% (p < 0.05) decrease in diameter and a 6.5% (p > 0.05) increase in wood density for the hybrids. On the contrary, E. badjensis demonstrated a noteworthy 22% increase in wood density (p < 0.05), while showing a corresponding 0.6% growth increase (p > 0.05), as measured by the diameter at breast height. Drill resistance measurement results indicated that E. nitens × E. globulus’ amplitude ranged from 20.1% to 26.6%, while E. badjensis’ ranged from 20.8% to 27.2%. The study revealed a high correlation between resistance amplitude and wood density, with coefficients of 0.97 observed for E. nitens × E. globulus and 0.84 for E. badjensis (p < 0.05). These findings fall within the range reported in similar studies involving Eucalyptus spp. The primary focus of the research was to assess the growth potential and wood quality of novel Eucalyptus spp. under conditions of water limitation. The study also explored the utility of drill resistance as a predictive measure for evaluating wood density as an indicator of wood quality.

The Effect of Water Availability on the Carbon Content of Grain and Above- and Belowground Residues in Common and Einkorn Wheat.

The carbon (C) fixed by crops, which is exported with harvest and retained as postharvest residues in a field, is important for calculating the C balance. The aim of this study was to determine the effect of water availability on the C content in whole wheat plants. In a three-year field trial, the weights of grain, straw, chaff, stubble, and roots of two cultivars of winter wheat (Triticum aestivum L.) and one cultivar of einkorn wheat (Triticum monococcum L.) and their carbon contents were determined in water stress, irrigation, and rain-fed control treatments. The water availability, year, and cultivar had a significant influence on the C content in aboveground plant parts, but the effect of water on grain C was weak. The C content decreased with irrigation and increased with drought, but the differences were small (at most, 3.39% in chaff). On average, the C contents of grain, straw, chaff, and roots reached 45.0, 45.7, 42.6, and 34.9%, respectively. The amount of C exported with grain and left on the field in the form of postharvest residues depended on the weight of the total biomass and the ratio of grain to straw and residue. Whole plant C yield reached 8.99, 7.46, and 9.65 t ha-1 in rain-fed control, stressed, and irrigated treatments, respectively, and 8.91, 9.45, and 7.47 t ha-1 in Artix, Butterfly, and Rumona, respectively. Irrigation significantly increased the C content in grain and straw (but not in chaff, stubble, and roots) in comparison with water shortage conditions. On average, a grain yield of 1 t ha-1 corresponded to an average export of 0.447-0.454 t C ha-1 in the grain of all cultivars and inputs of 0.721, 0.832, and 2.207 t C ha-1 of residue to the soil in the form of straw and postharvest residue in the two cultivars of common wheat and one of einkorn. The results of the study provided reliable data for the calculation of the C balance of wheat under conditions of different water availability.

Performance evaluation of alternate wetting and drying irrigation for rice cultivation

An experiment was conducted during the 2009-2010 Boro season at the Shahjalal Science and Technology University campus, Sylhet, Bangladesh, to investigate the impact of alternate wetting and drying irrigation (AWDI) on rice production. Using a randomized complete block design (RCBD), four irrigation treatments were applied to a modern variety (MV) of rice (BRRIdhan 28). One control treatment, T0, maintained a continuous standing water depth of 1-5 cm. Water was irrigated to three AWD treatments, T1, T2, and T3 when the water level dropped 10, 20, and 30 cm below ground level, respectively. In spite of the fact that treatment T0 produced the highest grain yield (4.90 t/ha), its water use efficiency was 38.64 kg/ha/cm. Compared to treatment T1, which produced 4.68 t/ha, treatment T1 had a water use efficiency of 41.86 kg/ha/cm. Treatments T2 and T3 yielded 3.96 t/ha and 3.63 t/ha, respectively. When water levels fall below 10 cm below ground level, treatment T1 may be the best option for rice cultivation in conditions of limited water availability.

Impact of Source, Sink Manipulation on Sunflower Yield Physiology under Different Water Availability Conditions

Impact of Source, Sink Manipulation on Sunflower Yield Physiology under Different Water Availability Conditions

Projected changes in heatwaves and its impact on human discomfort over India due to global warming under the CORDEX-CORE framework

Due to climate change, rapid warming and its further intensification over different parts of the globe have been recently reported. This has a direct impact on human health, agriculture, water availability, power generation, various ecosystems, and socioeconomic conditions of the exposed population. The current study thus investigates the frequency and duration of heatwaves, human discomfort, and exposure of the human population to these extremes using the high-resolution regional climate model experiments under two Representative Concentration Pathways (RCP2.6, RCP8.5) over India. We find that more than 90% of India will be exposed to uncomfortable warm nights by the end of the 21st century with the highest rise over western India, Madhya Pradesh (MP), Uttar Pradesh (UP), Punjab, and the Haryana region. States like Odisha, Chhattisgarh, eastern parts of MP and UP, and some parts of J&K will be the worst hit by the intense and frequent heatwaves and human discomfort followed by the densely populated Indo-Gangetic plains under RCP8.5. Strict enforcement of the stringent policies on stabilization of population growth, improvement of local adaptive capacities, and economic status of the vulnerable population along with enforcing effective measures to curb greenhouse gas emissions are important to reduce human exposure to future heat stress. We demonstrate that a proper mitigation-based development (RCP2.6) instead of a business-as-usual scenario (RCP8.5) may help to reduce 50–200 heatwave days, 3–10 heatwave spells, and 10–35% warm nights over the Indian region. Consequently, this can avoid the exposure of 135–143 million population to severe discomfort due to extreme heat conditions by the end of the 21st century.

Effect of scheduling of irrigation on yield and economics of safflower genotypesunder limited water availability conditions

A field experiment was carried out to find out the effect of irrigation schedules for a suitable variety of safflower (Carthamus tinctorius L.) using 3 genotypes and seven irrigation schedules.. The seed yield of safflowerwas significantly influenced by safflower genotypes. The seed yield of safflower was significantly higher in DSH 184 (1253 kg /ha) which was followed by TSF-1 (1123 kg /ha). While NARI-6 recorded the lowest yields (972 kg /ha). The seed yield of safflower differed significantly due to the application of irrigation at critical stages of the crop. The crop received 3 irrigations each at the Stem elongation stage + Early flowering stage + Seed filling stage resulting in significantly superior yields (1489 kg/ha) which was followed by 2 irrigations each at the Stem elongation stage + Early flowering stage (1408 kg/ha) and 2 irrigations each at the Stem elongation stage + Seed filling stage (1303 kg/ha). Crop grown completely under rainfed conditions recorded the lowest yield (776 kg/ha). The seed yield increased up to 47.88% by providing 3 irrigations each at Stem elongation, Early flowering and Seed filling stages as compared to rainfed conditions.

Drought’s Impact on Growth and Strategies to Mitigate its Effects on Potato Cultivation: A review

The potato is the third most widely produced cereal in the world, behind rice and wheat. The contemporary potato is vulnerable to yield loss in prolonged droughts. Droughts are becoming more severe and common as a result of global warming. Because of its shallow root system, potatoes are easily parched. The occurrence of drought and water shortage has substantial ramifications for the production of potatoes, exerting influence on both the volume and quality of potato harvests. Potatoes are a crop that needs a substantial amount of water, since they rely on a regular and sufficient water supply during their whole growth cycle. The presence of drought conditions or limited water supplies might result in many adverse consequences for the cultivation of potatoes. Potato plants are susceptible to experiencing stunted growth and development as a direct result of the water stress that is brought on by drought conditions. The restricted supply of water adversely affects the absorption of vital nutrients by plants, resulting in imbalances and deficits in nutritional levels. These conditions may lead to inhibited development, diminished leaf surface, and a lower quantity of tubers. Water stress circumstances have a considerable negative impact on the total production potential of potato crops. Moreover, the phenomenon of water shortage has a significant impact on the physiological mechanisms of potato plants, specifically in relation to essential functions like photosynthesis and transpiration. A scarcity of water during the tuber bulking phases might lead to a reduction in potato size, hence impacting its commercial worth. The use of effective irrigation systems, such as drip irrigation or precision sprinklers, has the potential to optimize water usage and minimize losses resulting from evaporation. The use of water conservation methods and the adoption of drought-resistant potato cultivars are crucial solutions for mitigating the effects of water shortage on potato farming. Through the use of these procedures, farmers have the ability to augment the resilience of their potato crops and guarantee the attainment of sustainable production, even when faced with conditions of low water availability.

Farmers’ perspectives on water availability in the lower Volta Delta region in Ghana

Smallholder farmers in the lower Volta Delta of Ghana operate in a risky and uncertain context due to water scarcity. However, the conventional analyses of water availability have mainly focused on drought, rainfall occurrence, and other climatic or weather elements, using secondary biophysical data with relatively little emphasis on farmers’ perceptions and how socioeconomic factors contribute to the vulnerability of farming in the lower Volta Delta. This study examines farmers’ perceptions of vulnerability to water availability to determine how perception is socially constructed and differentiated in various locations. The study was conducted using qualitative research methods in the Ada East, Ada West, South Tongu, and Anloga Districts in the lower Volta Delta of Ghana. Findings reveal that climate is not the only stressor on livelihoods in the area. Farmers perceive their livelihoods as vulnerable to socioeconomic stressors, including limited freshwater and groundwater resources. The perceived severity of water availability conditions determines farmers’ response strategies, such as crop selection, planting dates, irrigation strategies, and other agronomic practices. These findings have important implications for researchers, agricultural extension agents, and policymakers to design appropriate measures and approaches to deal with water scarcity for farming in the region. The study also contributes valuable insights into the loss and damage incurred by farmers due to climate change and variability in the region.

Irrigation in Jatropha curcas L. cultivation and its effect on biomass for bioenergy generation

The use of biomass as a source of bioenergy has intensified in recent years and has gained strength in replacing fossil fuels and their derivatives. Jatropha curcas L. oil is currently used as a raw material for the production of biodiesel through the physical extraction of the fruit, generating a large amount of waste. The heterogeneity characteristics of these materials impose the need for thermal pre-treatments for their recovery, such as torrefaction. Thus, this study aimed to investigate the biomass of Jatropha curcas as affected by water availability and its response to the torrefaction process. This research analyzed the biomass physical, chemical, and energy characteristics. TGA/DTG evaluated the thermo-degradation profile, and infrared spectroscopy (FTIR) determined the aromatic chemical structure. The fresh biomass of epicarp and cake presented different behaviors regarding water availability conditions, as variations in lignin contents from 29% to 2.7% and 30.9%–5.7%, respectively, and extractive range from 45.3% to 19.8% and 44.6%–21.6%, respectively. Torrefaction contributed to the increase in physical-chemical characteristics such as lignin and fixed carbon levels, from 29% to 82.4% and 19.8%–52.7%, respectively, and net calorific value of biomass, valuing them for energy use, as well as to decrease in the content of volatile materials from 80.7% to 71.8%. Using renewable biomass of Jatropha curcas cake and epicarp for energy purposes contributes to the reduction of environmental impacts by reducing the disposal of these residues in the environment, providing a sustainable and more efficient destination.

Leaf and wood functional traits explain the strategies developed by Byrsonima sericea (Malpighiaceae) to survive in Atlantic Forest ecosystems under water and light variations

The Atlantic Forest is a heterogeneous biome comprised of different phytophysiognomies with contrasting microclimatic and edaphic characteristics, such as sandbanks and forests. Sandbanks are ecosystems with low water availability and high irradiance, requiring leaf and wood specific adjustments from species to survive. On the other hand, tropical rain forests lack a pronounced dry season, providing enough resources to allow competition from light-demanding trees and sustaining a spectrum of shade tolerance for understory species. To better understand how functional traits are determined, it is necessary to evaluate variables that are site-specific, i.e. that are displayed within an organism in different environments. We aimed to assess how does variation in the functional traits of the leaf and wood of Byrsonima sericea influence the survival abilities of this species to thrive under contrasting scenarios of light and water availability. Also, which set of morpho-anatomical and physiological traits are considered to be site-specific responses that are affecting positively the capacity of the species to adapt in these contrasting scenarios of the Atlantic Forest? The high irradiance in sandbank shaped functional traits of B. sericea leaves that allowed an allocation strategy of the available resources, with investment in leaf mass rather than in trunk biomechanics and hydraulic efficiency. The higher leaf density through smaller and numerous cells along with higher stomatal density and area, facilitating CO2 diffusion, were associated with a greater photosynthetic capacity and greater intrinsic water use efficiency. As in the forest, light is a limiting factor for species to grow, the fluctuating light over a short timescale can influence whole plant performance, thus requiring an investment in trunk biomechanics. Additionally, a set of wood traits in the forest was related to water availability favoring wider vessel elements with thicker walls, increasing the theoretical hydraulic conductivity, even though it implicated a higher vulnerability to cavitation. Our study has demonstrated that variation of traits of different plant structures, such as the leaf and wood, within a species has direct implications in the survival strategies at each environmental conditions of light and water availability. It is also stated that there are different sets of functional traits which are responsible for allocation strategies, leading to specific trade-offs that allow the species to display site-specific responses in order to survive.

Taxonomic and functional characteristics of xerotolerant culturable bacterial community of Negev desert soil

Despite the significant expansion of the geography of soil microorganisms studies in various, including extreme natural environments, research on the biodiversity and metabolic activity of soil microbial communities under conditions of moisture deficiency are few. Biodiversity of culturable bacteria isolated from the surface horizon of the Negev desert soil (Aridic Calcisol) after pre-incubation of soil samples under the conditions of low water availability has been studied. An increase in the diversity of culturable bacteria after pre-incubation was revealed in comparison with the community isolated from the native soil. From the native and pre-incubated samples, 153 phenotypically unique pure cultures of bacteria from 22 genera belonging to the phyla Actinomycetota, Pseudomonadota, Bacillota, and Bacteroidota were isolated and identified. The taxonomic diversity of culturable bacteria isolated from the sample pre-incubated at a water activity (Aw) of 0.90 was two times higher than that obtained from the native soil. The strain of the genus Pedobacter has been identified, which may be a representative of a previously undescribed bacterial species. Bacteria of the genera Aerococcus, Bacillus, Brevibacterium, Staphylococcus, and Stenotrophomonas capable of growing at Aw 0.91 were found. One strain of the genus Microlunatus has been identified that is capable of growing on a nitrogen-free medium, exhibiting amylase and protease activity, and capable to growth on a medium with Aw down to 0.96. The obtained results confirm the hypothesis that arid ecosystems, in particular, desert soils and sediments, are a depository of a previously unexplored taxonomic diversity of bacteria with unique physiological properties that are promising for study and potential implementation in biotechnological processes.

Water use strategies of Nitraria tangutorum in the lake-basin region of the Badain Jaran Desert.

Information regarding plant water-use strategies is essential for understanding the hydrological processes and plant survival adaptation mechanisms in desert lake basin regions. To examine the water use strategies of plants in desert lake basin areas, water uptake patterns, water use efficiency, and water potential of Nitraria tangutorum were investigated at different distances from the lake duringhe growing seasons in the lake basin regions of the Badain Jaran Desert. The results indicate that N. tangutorum primarily absorbed groundwater in May (63.8%) and August (53.5%), relied on deep soil water in June (75.1%), and uniformly absorbed soil water from different layers in July. These observations could be explained by periodic fluctuations in the groundwater level and the consequent decrease in soil water availability, as well as plant root adjustments. As soil water availability decreases, N. tangutorum adapts to water variation by increasing its water use efficiency (WUE) and reducing its leaf water potential (Ψ). With intensified water stress, N. tangutorum gradually shifted from adventurous anisohydric regulation to conservative isohydric regulation. Thus, N. tangutorum responds to diverse degrees of environmental changes by altering its water-use strategy. A better understanding of the adaptive water use strategies developed by desert plants under varying water availability conditions provides insight into the diversity of species' reactions to long-term drought and quantifies the hydrological cycle of desert ecosystems against the background of worldwide climate warming.

Narrow root cone angle promotes deeper rooting, cooler canopy temperatures and higher grain yield in a rice (Oryza sativa L.) recombinant inbred line population grown under different water availabilities in aerobic production systems

Rice crops are one of the world’s major consumers of irrigation water. With water becoming more limited, water-saving aerobic production (AP) systems may provide an alternative to traditional flooded culture. Genotypes with narrow root cone angle (RCA) and subsequently deeper rooting systems are hypothesised as key for AP adaptation ensuring water uptake at depth. Using a recombinant inbred line (RIL) population and differential genotypes (narrow and wide RCA groups) derived from a Sherpa/IRAT109 cross, a glasshouse experiment and four field experiments with different water inputs in well-watered (WW, in two seasons), mild water deficit (MWD), and intermittent water deficit (IWD) conditions were carried out to characterise the relationship of RCA with grain yield (GY) and key physiological traits. Significant genotypic variation and group differences were found in root traits, canopy temperature and GY. Expression of genotypes with narrow RCA were found to be consistent across experiments and water availability conditions. Genotypes in the narrow RCA group produced a greater proportion of roots below 20 cm (7.4–17.7%), longer total root length (69.7%), cooler canopies (0.3–1.0 °C) and higher GY (14–62%) compared with wide RCA group. Two promising RILs were identified which expressed high GY in WW (12.0–13.4 t/ha) conditions while maintaining GY in IWD (up to 9.4 t/ha). Higher GY was obtained in genotypes with cooler canopies (r = −0.72) and narrow RCA (r = −0.39) in IWD. Narrower RCA was associated with higher total root length (r = −0.70) and higher stomatal conductance (r = −0.71) in the glasshouse and proportion of deep roots (r = −0.65) and cooler canopies (r = 0.66) in the field. To our knowledge, this was one of the foremost studies exploring and demonstrating such relationships in rice AP systems. Root traits determined in the field were congruent with the other root-related traits driving differences between RCA groups measured in the glasshouse providing confidence with the field phenotyping methods. This work demonstrated the advantage conferred by the development of narrow RCA in aerobic conditions, presented improved physiological understanding of RCA and with genomics assisted breeding, is considered valuable for the development of AP-adapted, sustainably produced rice.

Comparative Analysis of Growth and Physiological Responses of Sugarcane Elite Genotypes to Water Stress and Sandy Loam Soils.

Stumpy irrigation water availability is extremely important for sugarcane production in Pakistan today. This issue is rising inversely to river flow due to inadequate water distribution and an uneven rainfall pattern. Sugarcane growth faces a shortage of available water for plant uptake due to the low water-holding capacity of sandy loam soil, particularly under conventional flood irrigation methods. To address this problem, sugarcane clones were evaluated for their agronomic and physiological traits under conditions of low water availability in sandy loam soil. Ten cane genotypes, HSF-240, SPF-213, CPF-249, CP 77-400, S2008-FD-19, S2006-US-469, S2007-AUS-384, S2003-US-633, S2003-US-127, and S2006-US-658, were exposed to four levels of water deficit created through skip irrigations. These deficit levels occurred during the 9th, 11th, 13th, and 16th irrigations at alternate deficit levels between 2020 and 2022. Physiological data were collected during the tillering and grand growth stages (elongation) in response to the water deficit. The sugarcane clones S2006-US-658, S2007-AUS-384, and HSF-240 exhibited resistance to low water availability at both the tillering and grand growth stages. Following them, genotypes S2006-US-658, S2007-AUS-384, and HSF-240 performed better and were also found to be statistically significant. Clones susceptible to water deficit in terms of growth and development were identified as CP 77-400, S2008-FD-19, S2006-US-469, and S2003-US-633. These genotypes showed reduced photosynthetic rate, transpiration rate, stomatal conductance, relative water content, cane yield, and proline content under stressed conditions. Therefore, genotypes S2006-US-658, S2007-AUS-384, and HSF-240 were better performers concerning physiological traits under water deficit and sandy loam soil in both years. Moreover, a significant positive correlation was assessed between agronomic traits and photosynthetic rats. This study highlights that sugarcane can sustain its growth and development even with less irrigation frequency or moisture availability, albeit with certain specific variations.