Effects Of Water Stress Research Articles

Effects of water stress on chlorophyll fluorescence and growth of Rorippa amphibia: a well-adjusted invasive plant in China

Effects of water stress on chlorophyll fluorescence and growth of Rorippa amphibia: a well-adjusted invasive plant in China

Characterizing the hysteretic effects of water and salinity stresses on root-water-uptake

Characterizing the effects of previous water and salinity stresses is critical for the evaluation of plant water status, which, in turn, is essential for understanding soil-plant water relations and optimizing irrigation schemes. Recent research has found that hysteresis of plant response following water stress alone can be described by an exponential function of the stress degree on the previous day. To explore and quantify the effects of hysteresis concerning salinity stress and combined water-salinity stress, a hydroponic experiment and a soil column experiment on winter wheat, and a field experiment on cotton were conducted. Like water stress, previous salinity stress and combined water-salinity stress also resulted in hysteretic effects on root-water-uptake. Leaf stomatal conductance and plant transpiration rate of stressed crops could only recover gradually from a previous stressed status after re-watering. When stress was mild, compensatory recovery was found, while incomplete recovery occurred when stress was severe. Although the recovery process was closely related to stress history and type, a recovery coefficient was quantified universally with an exponential function of the stress extent on the previous day (with a coefficient of determination R2 ≥ 0.60). Consideration of hysteresis for water and salinity stresses with a mathematical model led to significant improvement in the simulation of both relative transpiration rate (R2 = 0.94, root mean squared error RMSE = 0.04, maximal absolute error MAE = 0.12) and soil water content (R2 = 0.90, RMSE = 0.01 cm3 cm–3, MAE = 0.03 cm3 cm–3), especially during the recovery periods severely affected by historical stress. Consideration of hysteresis is expected to benefit regulation of soil water and salinity and thus enhance water use efficiency. However, the mechanisms underlying hysteresis, especially the compensatory recovery mechanisms, still need to be further investigated.

Maize (Zea Mays L.) Response to Deficit Irrigation Levels at Different Growth Stages on its Yield and Water Use Efficiency at Koka, Central Rift Valley of Ethiopia

Water scarcity is among the major limitations for crop production. Improving water use efficiency of irrigated crops through water management options is crucial in water scarce areas. Field experiment was carried out at Wondo Genet Agricultural Research Center Koka Research site, to investigate the effect of water stress at different growth stage on yield and water use efficiency of maize. one optimum irrigation and eight growth stage based deficit levels(100% ETC at all growth stages, 75% ETC at all growth stages, 50% ETC at all growth stages, 75% ETC at development growth stage, 50% ETC at development growth stage, 75% ETC at mid growth stage, 50% ETC at mid growth stage, 75% ETC at late growth stage and 50% ETC at late growth stage) were imposed on maize (Zea mays L.) variety Melkassa II as a treatment and laid out in randomized complete block design (RCBD) with three replications. Results indicated that the different levels of growth stage based deficit levels had significant (p<0.01) effect on crop yield, harvest index and water use efficiency. Grain yield reduced with increased stress, whereas water use efficiency was increased with stress level increased. The highest grain yield of 6.4 t/ha and WUE of 1.01 kg/m3 were obtained at 100% ETC and 50% ETC at all growth stages, respectively. Also, 75% ETC at development stage and late stage treatments showed no significant variation with 100% ETC in grain yield. Water use efficiency observed at 75% ETC all growth stages treatment was statistically similar with that of 50% ETC at all growth stages treatment. Grain yield obtained from 50% ETC at mid growth stage was similar with 50% ETC at all growth stages, and water use efficiency was the least and this shows that maize was sensitive to moisture stress at mid growth stage than development and late growth stages. Therefore, maize could be irrigated at 75% ETC at all growth stages and by stressing development or late growth stages up to 50% ETC to increase water use efficiency with a small grain yield reduction for stressed scenario and for non stressed scenario with 100% ETC at all growth stages.

The role of salicylic acid in modulating phenotyping in spring wheat varieties for mitigating drought stress

Climate change-related droughts that recur frequently are one of the biggest obstacles to wheat (Triticum aestivum L.) productivity. Worldwide, attempts are being done to establish drought-resistant cultivars. However, progress is slow since drought tolerance is a complex trait controlled by numerous genes, and its expression is influenced by the environment. Phenotypic, biochemical physiological, and genotyping approaches are highlighted as critical research components for leveraging genetic variation in eight wheat genotypes. Treatments included eight spring wheat genotypes (IPK_040, IPK_046, IPK_050, IPK_071, IPK_105, WAS_007, WAS_024 and WAS_031), normal irrigation (NI), drought stress (D) (30% field capacity (FC)), normal irrigation with 0.5 mM SA (NSA), and drought treated with SA (DSA). The results revealed that there was a reduction in relative water content, an increase membrane leakage, and leaf chlorophyll content under drought stress. SA induced the defense responses against drought by increasing the osmolytes and the antioxidative enzymes activities. Compared to the NI group, the DSA treatment improved the water regulation, antioxidant capacity, and drought stress resistance. SA significantly reduced the deleterious effects of water stress on phenotyping more in WAS_ 024 and IPK_ 105 genotypes. The most responsive genotypes to salicylic acid were IPK_ 046 among the IPK genotypes, whereas WAS_031 genotype was amongst WAS genotypes based on the morpho-physiological traits. The findings of this study give a solid foundation for assessing drought resistance in T. aestivum and developing cultivation-specific water management methods.Graphical

Effects of Salicylic Acid on Physiological Responses of Pepper Plants Pre-Subjected to Drought under Rehydration Conditions.

Capsicum annuum L. has worldwide distribution, but drought has limited its production. There is a lack of research to better understand how this species copes with drought stress, whether it is reversible, and the effects of mitigating agents such as salicylic acid (SA). Therefore, this study aimed to understand the mechanisms of action of SA and rehydration on the physiology of pepper plants grown under drought conditions. The factorial scheme adopted was 3 × 4, with three water regimes (irrigation, drought, and rehydration) and four SA concentrations, namely: 0 (control), 0.5, 1, and 1.5 mM. This study evaluated leaf water percentage, water potential of shoots, chlorophylls (a and b), carotenoids, stomatal conductance, chlorophyll a fluorescence, and hydrogen peroxide (H2O2) concentration at different times of day, water conditions (irrigation, drought, and rehydration), and SA applications (without the addition of a regulator (0) and with the addition of SA at concentrations equal to 0.5, 1, and 1.5 mM). In general, exogenous SA application increased stomatal conductance (gs) responses and modified the fluorescence parameters (ΦPSII, qP, ETR, NPQ, D, and E) of sweet pepper plants subjected to drought followed by rehydration. It was found that the use of SA, especially at concentrations of 1 mM in combination with rehydration, modulates gs, which is reflected in a higher electron transport rate. This, along with the production of photosynthetic pigments, suggests that H2O2 did not cause membrane damage, thereby mitigating the water deficit in pepper plants. Plants under drought conditions and rehydration with foliar SA application at concentrations of 1 mM demonstrated protection against damage resulting from water stress. Focusing on sustainable productivity, foliar SA application of 1 mM could be recommended as a technique to overcome the adverse effects of water stress on pepper plants cultivated in arid and semi-arid regions.

Effects of Water Stress on Water Consumption, Water Use Efficiency of Different Wheat Varieties

Effects of Water Stress on Water Consumption, Water Use Efficiency of Different Wheat Varieties

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.

Mapping critical soil moisture thresholds of water stress for global grasslands

The critical soil moisture threshold (SMth) of plant water stress distinguishes whether vegetation is in an energy-limited or water-limited regime. Accurate quantification of SMth for grasslands holds significant implications for drought monitoring and efficient grassland management. However, our understanding of SMth within global grasslands remains limited. In this study, we investigated the relationship between SMth and environmental factors and mapped the global SMth for grasslands based on the estimated SMth across FLUXNET sites. Firstly, SMth was identified and estimated for 18 distinct grassland sites. Then, the factors significantly affecting SMth were investigated and the global SMth for grasslands was predicted using an empirical linear model. Our results showed that SMth was significantly positively correlated with mean annual soil moisture (SM), mean annual precipitation (PRE), and maximum annual LAI (LAImax), while negatively correlated with vapor pressure deficit (VPD) and shortwave radiation (RAD). These factors collectively constrain SMth well, with the coefficient of determination of 0.79. The estimated mean SMth for global grasslands from 2000 to 2021 is 27.8%, with a range from 1.3% to 55.2%. The SMth values are lower in the northern hemisphere than that in the southern hemisphere. The highest values of SMth, exceeding 40.0%, are mainly distributed in Brazil, Peru, Southern Europe, New Zealand and the Tibetan Plateau. In contrast, the lowest values, failing below 20.0%, are mainly distributed in Northern Canada, Greenland, Central African Savannah and Kazakhstan. The SMth is markedly lower in the arid region than that in the tropical and temperate regions. The quantified SMth in this study could provide a direct way to determine whether and to what extent grasslands are subjected to water stress, which would greatly facilitate the study of drought or water stress effects on vegetation growth for grassland ecosystems.

Rhizobacteria Isolated from Amazonian Soils Reduce the Effects of Water Stress on the Growth of Açaí (Euterpe oleracea Mart.) Palm Seedlings.

Euterpe oleracea Mart., also known for its fruit açaí, is a palm native to the Amazon region. The state of Pará, Brazil, accounts for over 90% of açaí production. Demand for the fruit in national and international markets is increasing; however, climate change and diseases such as anthracnose, caused by the fungus Colletotrichum sp., lead to decreased production. To meet demand, measures such as expanding cultivation in upland areas are often adopted, requiring substantial economic investments, particularly in irrigation. Therefore, the aim of this study was to evaluate the potential of açaí rhizobacteria in promoting plant growth (PGPR). Rhizospheric soil samples from floodplain and upland açaí plantations were collected during rainy and dry seasons. Bacterial strains were isolated using the serial dilution method, and subsequent assays evaluated their ability to promote plant growth. Soil analyses indicated that the sampling period influenced the physicochemical properties of both areas, with increases observed during winter for most soil components like organic matter and C/N ratio. A total of 177 bacterial strains were isolated from rhizospheres of açaí trees cultivated in floodplain and upland areas across dry and rainy seasons. Among these strains, 24% produced IAA, 18% synthesized ACC deaminase, 11% mineralized organic phosphate, and 9% solubilized inorganic phosphate, among other characteristics. Interestingly, 88% inhibited the growth of phytopathogenic fungi of the genera Curvularia and Colletotrichum. Analysis under simulated water stress using Polyethylene Glycol 6000 revealed that 23% of the strains exhibited tolerance. Two strains were identified as Bacillus proteolyticus (PP218346) and Priestia aryabhattai (PP218347). Inoculation with these strains increased the speed and percentage of açaí seed germination. When inoculated in consortium, 85% of seeds germinated under severe stress, compared to only 10% in the control treatment. Therefore, these bacteria show potential for use as biofertilizers, enhancing the initial development of açaí plants and contributing to sustainable agricultural practices.

Effect of Anti-Transpiration and Potassium on Water Use Efficiency and Water Consumption under Water Stress Conditions to Climate Change Resistance

Climate change impact serious threats to global food security due to changes in water requirements resulting from the variation and instability of the spatial and temporal distribution of rainfall and the lack of water availability. Therefore, our research aims to use anti-transpiration agents that reduce plant water consumption, thus providing adequate amounts of water for agriculture in arid areas. A field experiment was conducted under water stress conditions during the winter seasons 2022-2023 and 2023-2024. The study included three levels of water stress, which are depletion of 40, 55 and 70% of the available water at a depth of 20 cm for the first three irrigations and a depth of 30 cm for the remaining irrigations and for the three treatments in succession. Anti-transpiration was added from different sources, which are kaolin, paraffin wax, silicon and potassium, in addition to the comparison treatment (spraying with water only). The results showed significant differences between the depletion treatments, as the 40% depletion treatment of the available water was significantly superior in most of the characteristics of the crop and its components, as the amount of increase in the grain yield was 62.24 and 64.22% for the two seasons in succession, compared to the 70% depletion treatment of the available water, which gave the lowest averages for all the studied characteristics. The irrigation treatment after depleting 40% of the available water was characterized by the best water use efficiency of 1.60 and 1.44 kg m-3 for the two seasons respectively, compared to the treatment of depleting 70% of the available water, which gave the lowest water use efficiency of 1.14 and 1.02 kg m-3 for the two seasons respectively. Spraying with anti-transpiration and potassium led to a significant increase in the yield and all its components compared to the comparison treatment (spraying with water only), which gave the lowest averages for all the studied traits, as spraying with potassium and kaolin gave a significant increase in most of the studied traits. Also, anti-transpiration and potassium, represented by potassium and kaolin, had a significant effect on water use efficiency, as the increase amount when spraying with potassium was 45.87 and 46.93% for the two seasons respectively compared to the comparison treatment (spraying with water only). As for the actual water consumption, we find an increase in the values ​​of water consumption and the number of irrigations in the comparison treatment (spraying with water only) compared to the anti-transpiration and potassium treatments, as the anti-transpiration and potassium provided water at a depth of 550, 414 and 405 m3 ha-1 for the first season and 615, 375 and 393 m3 ha-1 for the second season for the depletion treatments of 40, 55 and 70% of the available water, respectively, compared to the comparison treatment (spraying with water only). This increase is not small when applied to large areas and providing additional agricultural areas that can be invested. These findings suggest that targeted use of these treatments can effectively mitigate the effects of water stress, improving wheat production and resource efficiency in water-limited environments.

The Effect of Water on Gas-Containing Coal with Cyclic Loading: An Experimental Study

In deep mining engineering, coal often is subjected to the influence of cyclic loading and water. In order to study the effect of water on gas-containing coal with cyclic loading, the pore evolution, permeability and energy dissipation of gas-containing coal under the effects of water and cyclic axial stress were analyzed in depth. The results showed that with the increase of water content, dissipation energy and permeability of coal samples decreased gradually. The presence of water weakened the increase in micropores and mesopores and promoted the increase in macropores during the cyclic loading process. Compared to dry coal samples, the ratio of micropores and mesopores in saturated coal samples decreased by 0.8872%, while the proportion of macropores increased by 0.0341%. On the basis of the above, a new formula for calculating the dissipation energy of gas-containing coal under the effects of water was proposed. A new damage variable based on energy dissipation was proposed. Finally, a theoretical model was derived to describe the permeability of gas-containing coal under the effects of water and cyclic axial stress.

Phenotypic plasticity of water-related traits reveals boundaries to the adaptive capacity of a dominant European grass species under increased drought

The intensification of droughts due to climate change is a global concern, and many plant species face increasing water deficits. Understanding the role of phenotypic plasticity in plant adaptation to these changing conditions is crucial. This research focuses on Bromopsis erecta, a dominant perennial grass in European and Mediterranean grasslands, to predict its potential adaptation to climate change. We assessed plants from shallow and deep soils (i.e., with contrasting water reserves) of a Mediterranean rangeland in southern France, and tested the effect of six years of experimentally increased summer drought compared to the ambient conditions on plant traits, survival and abundance. In both field and common garden experiments, we measured water-related traits, including static traits under non-limiting water conditions, and dynamic traits, such as rates of trait variation during drought. Trait plasticity was determined as a reaction norm to increasing soil water stress and was tested against changes in B. erecta abundance over the past decade, including the study period. Trait plasticity was detected only for leaf dry matter content (LDMC), revealing that the resource strategy of B. erecta became more conservative over less than a decade with higher LDMC and leaf thickness according to the plant economic spectrum. No plasticity was found for osmotic potential or specific leaf area. The variability of other traits was ascribed to the possible lagging effect of previous water stress and was associated more with soil depth than with previous summer drought intensity. The abundance decline of B. erecta, which dropped from 20 % to around 5 % in shallow soils, was not associated with the plasticity of LDMC but was positively correlated with variations in leaf base membrane damage, meaning unexpectedly, that plants exposed to the most severe summer drought also had the most sensitive leaf base membranes, a possible sign of maladaptive trait plasticity in the population. This key trait response reveals boundaries to the adaptive capacity of this perennial grass to survive pluri-annual drought.

Using Dynamic Laser Speckle Imaging for Plant Breeding: A Case Study of Water Stress in Sunflowers.

This study focuses on the promising use of biospeckle technology to detect water stress in plants, a complex physiological mechanism. This involves monitoring the temporal activity of biospeckle pattern to study the occurrence of stress within the leaf. The effects of water stress in plants can involve physical and biochemical changes. Some of these changes may alter the optical scattering properties of leaves. The present study therefore proposes to test the potential of a biospeckle measurement to observe the temporal evolution in different varieties of sunflower plants under water stress. An experiment applying controlled water stress with osmotic shock using polyethylene glycol 6000 (PEG) was conducted on two sunflower varieties: one sensitive, and the other more tolerant to water stress. Temporal monitoring of biospeckle activity in these plants was performed using the average value of difference (AVD) indicator. Results indicate that AVD highlights the difference in biospeckle activity between day and night, with lower activity at night for both varieties. The addition of PEG entailed a gradual decrease in values throughout the experiment, particularly for the sensitive variety. The results obtained are consistent with the behaviour of the varieties submitted to water stress. Indeed, a few days after the introduction of PEG, a stronger decrease in AVD indicator values was observed for the sensitive variety than for the resistant variety. This study highlights the dynamics of biospeckle activity for different sunflower varieties undergoing water stress and can be considered as a promising phenotyping tool.

Effects of different water stresses under subsurface infiltration irrigation on eggplant growth and water productivity

Soil moisture deficiency limits eggplant growth and affects the yield and quality. Identifying an appropriate deficit irrigation strategy to enhance irrigation water productivity is an urgent task. Additionally, the dynamic response of eggplants to water stress at various phenological stages needs further clarification. In this study, eggplants were used as experimental materials, with field capacity (FC) (Senyigit et al.) serving as the irrigation standard. Two levels of deficit irrigation treatments (60 % FC and 50 % FC) were applied at three key phenological stages of eggplant (seedling stage, flowering and fruiting, and prime fruit stage). A randomized block design was used with non-deficit irrigation (80 % FC) during the phenological stages as the control (W1), resulting in seven treatments, each with three replicates. The results showed that at the same phenological stage, plant height, stem diameter, leaf area index (LAI), dry matter accumulation, total fresh root weight, total root length, total root surface area, and total root volume decreased as the irrigation threshold was lowered. The content of vitamin C, soluble sugars, souble proteins, and crude fiber increased as the irrigation threshold decreased. Leaf photosynthetic parameters (photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and intercellular CO2 concentration (Ci)) were positively correlated with the irrigation threshold. The W1 treatment had the highest yield (89.1 t·ha−1 in 2018; 88.8 t·ha−1 in 2019), followed by the W2 treatment (86.1 t·ha−1 in 2018; 85.6 t·ha−1 in 2019). Water deficit during the prime fruit stage (W6, W7) had the most significant impact on yield. W1 had the highest water productivity (19.4 kg·m−3 in 2018; 19.2 kg·m−3 in 2019), with no significant difference from W2 (19.4 kg·m−3 in 2018; 19.0 kg·m−3 in 2019). Using the Jensen function, the water sensitivity of eggplants at different phenological stages was ranked as follows:prime fruit stage > flowering and fruiting stage > seedling stage. Path analysis indicated that dry matter accumulation, single fruit weight, and single plant yield were important indicators affecting yield. Considering irrigation amount, eggplant growth, fruit yield and quality, and water productivity, the optimal deficit irrigation thresholds for eggplants in arid regions are determined to be 60 % FC during the seedling stage, 60 % FC during the flowering and fruiting stage, and 80 % FC during the prime fruit stage. The findings of this study offer valuable insights for precision agricultural irrigation practices.

Effects of water stress on apoplastic barrier formation in soil grown roots differ from hydroponically grown roots: Histochemical, biochemical and molecular evidence.

In root research, hydroponic plant cultivation is commonly used and soil experiments are rare. We investigated the response of 12-day-old barley roots, cultivated in soil-filled rhizotrons, to different soil water potentials (SWP) comparing a modern cultivar (cv. Scarlett) with a wild accession ICB181243 from Pakistan. Water potentials were quantified in soils with different relative water contents. Root anatomy was studied using histochemistry and microscopy. Suberin and lignin amounts were quantified by analytical chemistry. Transcriptomic changes were observed by RNA-sequencing. Compared with control with decreasing SWP, total root length decreased, the onset of endodermal suberization occurred much closer towards the root tips, amounts of suberin and lignin increased, and corresponding biosynthesis genes were upregulated in response to decreasing SWP. We conclude that decreasing water potentials enhanced root suberization and lignification, like osmotic stress experiments in hydroponic cultivation. However, in soil endodermal cell suberization was initiated very close towards the root tip, and root length as well as suberin amounts were about twofold higher compared with hydroponic cultivation.

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.

The effect of water stress on growth and development of mango (Mangifera indica L.) varieties in lower Eastern region of Kenya

The effect of water stress on growth and development of mango (Mangifera indica L.) varieties in lower Eastern region of Kenya

Research on the influence of major ions in weakly alkaline mine water on anchor cable corrosion and protection technique

Anchor cables in water-rich roadways frequently experience severe corrosion and resultant fractures due to the combined effects of mine water and high stress. However, the precise factors influencing corrosion on these cables remain ambiguous, presenting challenges to roadway support safety. This study investigated the impact of major ions present in weakly alkaline mine water on anchor cable corrosion using salt spray corrosion experiments. The results indicated that major anions such as Cl- notably influence anchor cable corrosion, which primarily manifested as pitting corrosion. The nominal yield strength decreased by 95.68–156.01 MPa, and the nominal tensile strength decreased by 133.44–202.77 MPa because of a decrease in the cross-sectional area. During the corrosion process, major anions such as Cl- continuously degraded the passivation film on the surface of the anchor cable, exposing its internal metal structure and exacerbating corrosion until eventual fracture failure occurred. Therefore, this paper proposes a corrosion protection technique for mine anchor cables to realize superior protective effects compared to conventional anchor cables used concurrently in field applications.

Does the soil microbial community facilitate Mimosa pudica's biological performance under abiotic stress? Growth, tolerance mechanisms, and seismonastic behaviour

Climate change effects such as soil salinisation or drought dramatically affect native and potentially invasive plant species. Mimosa pudica, originally native to South America but spread to Africa and Asia, exhibits great adaptability to disturbed environments in tropical and subtropical areas. It has become a model organism for studying thigmomorphogenetic behaviour due to its ability to display fast responses to mechanical stimuli. We investigated the effects of salt and water stresses on M. pudica in interaction with a Mediterranean coastal dune microbial community by growing plants on soils collected from dunes near Valencia, Spain. Plant biomass, potential mechanisms of stress tolerance, seismonastic response, and phenology were assessed. Abiotic stress, particularly salt stress, adversely affects plant performance and seismonasty. Mimosa pudica, however, displayed the blockage of Na+ transport at the root level as a primary defence mechanism against salinity. When exposed to natural soils, plants produced more leaves and flowers, with lower flower abortion rates than plants in a sterile substrate, and the stimulated plants displayed faster responses across time before reaching a plateau, while the recovery increased with time. Our results highlight the need for integrative and multidisciplinary approaches to understand plant-abiotic stress-microorganisms interactions. In M. pudica, soil microorganisms had weak or no effects on biomass or biochemical stress markers; however, their presence strongly improved reproductive traits and seismonasty, thus facilitating potential plant establishment in a new environment.

Study on the fractional creep model of roadway filling paste under the coupling effect of pore water pressure and stress

Filling paste in deep roadways is significantly affected by groundwater, especially high pore water pressure, which increases the complexity and variability of the filling paste's mechanical properties. To explore the creep characteristics and long-term stability of filling paste under varying pore water pressure, the MTS815.03 test system is used to conduct creep tests under different pore water pressures and stress. Then the creep deformation of the filling paste under the complex pressure field of static pore water pressures is analyzed. Finally, through the one-to-one correspondence between the numerical simulation of the creep model and the characteristic points of the creep curve, a method for determining the creep parameters under the complex pressure field of static pore water pressures is proposed. Results show that the creep test curves of filling paste under different pore water pressures and stress are in good agreement with the model curves. This shows that the creep constitutive model in this research can better reflect the whole process of creep deformation of filling paste. The result also verifies the rationality of the proposed method to determine creep model parameters. The newly proposed creep model can effectively compensate for the traditional Nishihara model, which is inability to reflect the acceleration of creep and can more accurately describe the creep characteristics of the primary and steady-state creep stages.