Levels Of Moisture Stress Research Articles

Tree diversity’s impact on coarse woody debris biomass and spatial stability under different moisture stress levels in temperate forests, South Korea

Tree diversity’s impact on coarse woody debris biomass and spatial stability under different moisture stress levels in temperate forests, South Korea

Altered physiological response in drought stressed rice plants upon root colonization with the beneficial endophytic fungus Piriformospora indica under field conditions

We studied the physiological and biochemical responses of rice plants colonized by the root endophytic fungus Piriformospora indica under varying moisture stress levels that consisted of ideal (non-stress), mild, moderate, severe, very severe, and extremely severe stress imposed by altering depth of irrigation and frequency in a summer field crop. Colonization by P. indica exhibited distinctive drought defensive effects characterized by the enhanced production of proline, which contributed to improved plant resilience to drought stress, alleviating the harmful oxidative stress. In colonized plants that were under extremely severe stress, proline levels in leaf tissues rose by 18% during panicle initiation (PI) and by 21% during the flowering stage, compared to the uninoculated plants. P. indica colonization also enhanced the relative leaf water content and cell membrane stability in plants. Under extremely severe stress, colonized plants displayed improved cell membrane stability (57% and 48%) at PI and flowering, representing 29% and 8% improvement, respectively, over the non-colonized plants under stress. Endophyte colonized plants demonstrated increased resistance to drought stress with enhanced chlorophyll stability when compared to stressed plants that were not colonized. Fungal colonization also enhanced the growth and resilience of rice plants under drought, resulting in a remarkable 37% increase in grain yield compared to non-colonized plants.

Irrigation scheduling for high value vegetable crops grown under protected cultivation in the hilly ecosystem of north-east India

Irrigation scheduling plays a vital role in the efficient utilization of water to obtain optimum yield, particularly for high value crops grown under protected conditions. The present experiment was conducted during 2020–22 at Horticulture Experimental Farm, ICAR-Research Complex for North Eastern Hill Region, Umiam, Meghalaya to standardize the irrigation scheduling (IS) (5, 7, and 10-days interval) in high-value vegetable crops [tomato (Solanum lycopersicum L.), capsicum (Capsicum annuum L.) and king-chilli (Capsicum chinense Jacq.)] grown under naturally ventilated low-cost polyhouse in the mid-hill conditions of Meghalaya. The results revealed a significant effect of IS on plant growth (reduction in plant height, leaf area) and yield attributes (fruit setting, fruit size, fruit weight and total yield) of the crops with an increase in level of moisture stress. The highest yield of tomato (82.7 t/ha), capsicum (40.8 t/ha) and king-chilli (11.8 t/ha) was recorded in the 5-day interval of IS and on increasing the IS interval to 7-days, the yield decreased by 28.7, 36.1 and 35.7%, respectively. Among the crops, capsicum was found to be more sensitive to water stress, followed by king-chilli and tomato. Among the crops, water productivity with respect to irrigation water was maximum in tomato (60.0 g/kg) followed by capsicum (17.2 g/kg) and king-chilli (10.0 g/kg). Among the varieties grown, Megha Tomato-3 of tomato, hybrid Mahabharat of capsicum and landrace Red Long of king-chilli were found superior for growth and yield attributes at different levels of moisture regime. The farmers of the region can get higher yield using identified varieties with irrigation at 5-days intervals.

Enhanced metabolite yield with compensatory biomass reduction revealed by moisture stress induction in <i>Centella asiatica</i> (L.)

The exposure to any kind of stress tends to accelerate the secondary metabolism in medicinal plants increasing the production of secondary metabolites. The present investigation was undertaken to study the effect of moisture stress (100, 75, 50, 25 and 10% pot capacity) and control (as without plant) on growth, yield and metabolite content of Centella asiatica var. ‘Arka Prabhavi’, for two growing seasons under polyhouse conditions. Results revealed that moisture stress treatments had a significant effect on all observed growth and yield traits. Plants maintained at 100% PC exhibited luxurious vegetative growth with maximum leaf length (6.28 cm), leaf breadth (8.14 cm), petiole length (22.32 cm) and fresh biomass yield (164 g/pot). Cumulative water transpired and water use efficiency of the plants was also observed to be maximum at 100% PC. In contrary to biomass yield, increased asiaticoside (1.864%, 1.892%), madecassoside (2.856%, 3.382%) and total triterpenoid content (5.356%, 5.578%) at higher moisture stress levels of 75% and 50% PC, respectively, was observed. Hence, it is appropriate to grow Centella either at 100% or 75% PC to get optimum biomass and metabolite yield on a commercial scale.

Phenotypic and yield responses of common bean (Phaseolus vulgaris l.) varieties to different soil moisture levels

BackgroundMorphological plasticity is one of the capacities of plants to modify their morphological appearance in response to external stimuli. A plant’s morphology and physiology are constantly tuned to its variable surroundings by complex interactions between environmental stimuli and internal signals.In most of plant species,, such phenotypic and physiological expression varies among different varieties based on their levels of particular environmental stress conditions. However, the morphological and yield responses of common bean varieties to different environmental conditions are not well known. The purpose of the study was to evaluate morphological and yield response of common bean to soil moisture stress and to investigate the morphological mechanism by which common bean varieties tolerate fluctuations in moisture stress.MethodsA pot experiment was carried out to investigate the effects of different moisture levels on the phenotypic and yield responses of common bean varieties. A factorial combination of five common bean varieties (Hirna, kufanzik, Awash-1, Ado, and Chercher) and three moisture levels (control, waterlogging stress, and moisture deficit stress) was used in three replications. Moisture stress treatments were started 20 days after planting, at the trifoliate growth stage. To evaluate the response of each variety, morphological and yield data were collected at week intervals.Main resultsThe results indicated that moisture levels and varieties had a significant influence on all growth parameters. Crop phenology was significantly influenced by the interaction effect of moisture level and variety. Exposing Hirna variety to moisture stress led to extended flowering and pod setting by 23 and 24 days, respectively, compared to the other treatments. The results showed that the phenotypic responses to moisture deficit and waterlogging stress varied between varieties. Waterlogging stress had a stronger reduction effect on the fresh weight, dry weight and leaf area of common bean varieties than moisture deficit and the control. Pods per plant, seeds per plant, grain yield per plant, and harvest index were significantly influenced by the varieties, moisture stress levels and their interaction. Except for Chercher and Hirna. However, varieties Ado, kufanzik and Awasha-1 did not show significant differences on the time of flower initiation due to moisture level. Biomass and growth in leaf fresh weight, leaf dry weight, leaf area, leaf number and plant height were significantly influenced by moisture level. When moisture deficit and waterlogging stress occurred, Ado and Awash-1 were more responsive to moisture stress than Hirna, Chercher, and Kufanzik.ConclusionHence, Hirna and Kufanzik varieties were found to be tolerant because they produced higher yields than the Chercher, Awash-1, and Ado varieties.

IoT based technological support for moisture stress experimental study on plants with stress prediction using deep learning

BACKGROUND: The increased depletion of ground water resources poses the risk of higher moisture stress environment for agriculture crops. The rapid increase in the moisture stress situation imposes the need of efficient agricultural research on determining the impact of moisture stress on variety of crops. OBJECTIVE: The prime objective of the proposed work is building an IoT based Plant Phenotyping Device for moisture stress experimental study on variety of crops with deep learning model for stress response detection. METHODS: In this work, IoT technology is used for building a proposed system for conducting the moisture stress experiments on plants and adopting the image processing and convolution neural network based model for stress prediction. RESULTS: The accuracy of the proposed system was experimentally evaluated and empirical results were satisfactory in maintaining the desired level of moisture stress. Performance analysis of LeNet, AlexNet, customized AlexNet and GoogLeNet CNN models were carried out with hyper-parameters variations on the leaf images. GoogLeNet achieved a better validation accuracy of 96% among other models. The trained GoogLeNet model is used for predicting the moisture stress response and predicted results were matched with manual observation of stress response. SIGNIFICANCE: The affirmative results of proposed system would increases its adoption for in-house precision agriculture and also for conducting various moisture stress experiments on variety of crops. The confirmative detection of moisture stress tolerance level of plant provides knowledge on minimum level of water requirement for plant growth, which in-turn save the water by avoiding excess watering to plants.

Permanent deformation characteristics of unsaturated subgrade soils under cyclic loading

Permanent deformation characteristics of unsaturated subgrade soils under cyclic loading

Biofilm producing plant growth promoting bacteria in combination with glycine betaine uplift drought stress tolerance of maize plant.

The escalating threat of drought poses a significant challenge to sustainable food production and human health, as water scarcity adversely impacts various aspects of plant physiology. Maize, a cornerstone in staple cereal crops, faces the formidable challenge of drought stress that triggers a series of transformative responses in the plant. The present study was carried out in two sets of experiments. In first experiment, drought stress was applied after maintaining growth for 45 days and then irrigation was skipped, and plant samples were collected at 1st, 3rd and 6th day of drought interval for evaluation of changes in plant growth, water relation (relative water content) and antioxidants activity by inoculating indigenously isolated drought tolerant biofilm producing rhizobacterial isolates (Bacillus subtilis SRJ4, Curtobacterium citreum MJ1). In the second experiment, glycine betaine was applied as osmoregulator in addition to drought tolerant PGPR to perceive modulation in photosynthetic pigments (Chlorophyll a and b) and plant growth under varying moisture stress levels (100, 75 and 50% FC). Results of the study revealed upsurge in root and shoot length, fresh and dry biomass of root and shoot besides increasing chlorophyll contents in water stressed inoculated plants compared to uninoculated plants. Glycine betaine application resulted in an additional boost to plant growth and photosynthetic pigments, when applied in combination with bacterial inoculants. However, both bacterial inoculants behaved differently under drought stress as evident from their biochemical and physiological attributes. Isolate SRJ4 proved to be superior for its potential to express antioxidant activity, leaf water potential and relative water contents and drought responsive gene expression while isolate MJ1 showed exclusive increase in root dry biomass and plant P contents. Though it is quite difficult to isolate the bacterial isolates having both plant growth promoting traits and drought tolerance together yet, such biological resources could be an exceptional option to be applied for improving crop productivity and sustainable agriculture under abiotic stresses. By exploring the combined application of PGPR and glycine betaine, the study seeks to provide insights into potential strategies for developing sustainable agricultural practices aimed at improving crop resilience under challenging environmental conditions.

Impact of Biotic and Abiotic Stress on Survival of Lac Insects Kerria lacca Kerr. on Pigeonpea (Cajanus cajan (L.) Millsp)

Cajanus cajan is generally grown in rainfed condition. The crop is also a good annual host plant of lac insect. C. cajan is widely reported to have biotic stress due to insect pests on it. Lac insect is phloem sap feeder and hence imparts biotic stress. The present field study was conducted to evaluate the percent survival of lac insects on C. cajan by adjusting different levels of biotic and abiotic stress on the host plant. The biotic stress due to insect pests on C. cajan was minimised with periodic spray of contact insecticides. The varying level of biotic stress i.e., No, Low, Medium, and High level was maintained on C. cajan plants with lac insects on it. The three levels of abiotic stress in this experiment were considered in terms of soil moisture stress. It was managed through irrigation per plant through drip system, it was considered that creating different levels of moisture stress in soil will impact the host plant. The abiotic stress was of three levels i.e., Low, Medium, and High. The result reveals that survival percent of Lac insect from brood lac inoculation to the harvest of lac crop was highest 37.52 percent on C. cajan with one primary branch and its secondary branches with lac insect (L1- Low biotic stress). It was 32.13 percent (W3- Low soil moisture stress). The study indicates that biotic and abiotic stress play a major role in the survival of K. lacca.

Endophytic fungus Piriformospora indica mitigates moisture stress in rice by modifying root growth

Endophytic fungus Piriformospora indica mitigates moisture stress in rice by modifying root growth

Exogenous Salicylic Acid Induced Drought Stress Tolerance in Immature Tea (<em>Camellia sinensis</em> L.) Plants

Salicylic acid (SA) has been known to induce drought tolerance in many plant species. In this study, we investigated the potential of exogenous application of SA to enhance drought tolerance in immature tea plants under glasshouse conditions at the Tea Research Institute in Talawakelle, Sri Lanka. One-year-old potted tea cultivars known for drought tolerance were used in the study. The plants were subjected to a drying cycle while being foliar sprayed with different concentrations of SA along with well-watered (WW), water-spray (WS) and no-spray (NS) treatments. Data were collected at 18 hours, 14 days after spraying (DAS), 21 DAS, and during the recovery after re-watering at 21 DAS. Based on the results obtained from the glasshouse study, the effective concentration of 150 mg L-1 SA was selected for further testing under field conditions in Talawakelle using three-year-old tea plants. The field experiment followed a randomized complete block design (RCBD) with three blocks. When the plants reached a moderate moisture stress level, they were foliar-sprayed with 150 mg L-1 SA, WS and NS treatments were included as controls. Data were collected at 7 DAS, 14 DAS, 21 DAS, and during the recovery phase after rain. The results showed that drought stress led to a decline in gas exchange parameters, relative water content, and an increase in the accumulation of osmolytes. However, the exogenous application of 150 mg L-1 SA significantly improved physiological processes such as gas exchange, osmolyte accumulation, and antioxidant activity, thus effectively enhancing drought tolerance in immature tea plants.

Rutting and Fatigue Resistance of High-Modulus Asphalt Mixture Considering the Combined Effects of Moisture Content and Temperature

High-modulus asphalt mixtures (HMAM) have been widely used in asphalt pavement in high-temperature areas of China, owing to their advantages in rutting and fatigue resistance. However, moisture and temperature interdependently determine the degradation of pavement performance of the HMAM, owing to the unique climatic conditions in summer in some high-temperature areas of China. There were few studies on the rutting and fatigue properties of the HMAM under the combined action of moisture contents and temperatures. Hence, the moisture absorption characteristics of the HMAM at different temperatures were analyzed. The rutting performance of the HMAM was investigated under different moisture contents and temperatures. The fatigue performance of the HMAM was investigated under different moisture contents, temperatures, and stress levels. Results show that: the rutting and fatigue resistance of the HMAM decrease with the increase in temperature and moisture content. The dynamic stability decreases by 8.9% at 40 °C and by 7.0% at 60 °C on average per 10% increase in moisture content and decreases by 22.7% on average per 10 °C increase in temperature. The fatigue life decreases by 4.1% at 15 °C and by 3.1% at 40 °C on average per 10% increase in moisture content and decreases by 31.3% on average per 10 °C increase in temperature. Finally, a prediction equation was established to predict the fatigue life under different moisture contents and temperatures.

Swelling and collapse behavior of unsaturated expansive subgrades stabilized with recycled glass

Swelling and collapse behavior of unsaturated expansive subgrades stabilized with recycled glass

Undrained Cyclic Loading Response of Subgrade Soil Subjected to Varying Moisture Content and Stress Level

Subgrades that are constructed from fine-grained cohesive soils undergo large settlements; therefore, the study of their deformation behavior is important to avoid early deterioration in the traffic infrastructure. In this study, the deformation behavior of two different types of cohesive subgrade soils at different compaction states has been addressed that considered the effect of influencing factors, such as water content, deviatoric stress, and confining pressure (σ3). The results from the unconsolidated undrained cyclic triaxial tests show that the deformation behavior of soil is highly influenced by the level of applied deviatoric stresses and moisture content on the wet side of optimum (WS) and is slightly affected by σ3 and moisture content on the dry side of optimum (DS). The elastic strain (ɛe) component showed a decreasing trend with an increase in the number of load cycles (N) and then attained a steady value toward a higher N; however, the plastic strain (ɛp) component continuously increased for a given magnitude of applied cyclic deviatoric stresses (σd,c). From the test results, logarithmic strain models were proposed to predict the long-term total (ɛt) strain and ɛp that developed in cohesive subgrade soils, which were subjected to various combinations of variations in moisture content and stresses. The proposed model has been compared with the existing model and shows better prediction ability with a coefficient of correlation (R2) of >95% in most cases.

POTENTIAL EFFECT OF BED-FURROW PLANTING IMPROVED THE WHEAT GRAINS PRODUCTIVITY UNDER DROUGHT STRESS

Limited water availability in future due to climate change may impact wheat yield and the food security. Therefore, it is necessary to find out the agronomic solutions to reduce the drought induce yield losses in wheat. Planting method affects wheat yield by changing the soil water status and root growth. This 2-year study was designed to evaluate the impact of various planting methods along-with water irrigation deficit regimes at different growth stages on wheat yield and net returns. The experiments were conducted in a randomized complete block design with three replications using two-way factorial arrangements. The experiment consisted of five planting methods (PM) viz. conventional broadcasting-PM, ridge-PM, bed-furrow-PM, gap-chat-PM and line-PM; and three water regimes viz., well-watered condition, mild and sever-terminal drought stress (TDS). The results revealed that wheat crop grown under bed-furrow-PM had better morphological growth under well-watered condition, and the crop grown under the same planting method performed better for morphological traits under mild-TDS and sever-TDS during both years. Irrometer Tensiometer was used to check the moisture stress level during terminal drought conditions. Better performance of wheat under mild-TDS and sever-TDS in bed-furrow-PM was the outcome of better antioxidants enzymatic and non-enzymatic activities which was later translated into better wheat yield and high net returns under water stress than other planting methods. In conclusion, bed-furrow-PM is the most suitable method for profitable wheat production in arid and semiarid region under water limited scenarios.

Plant growth-promoting rhizobacteria mediated moisture stress alleviation in the early stages of Rice (Oryza sativa L.) variety CO 51

Drought is one of the abiotic stresses that have a significant impact on agricultural growth across the world. Plant growth-promoting rhizobacteria (PGPR) inoculation in rice plants may be a viable and environmentally acceptable method of sustaining the development and yield of drought-stressed rice plants. The current study focused on the alleviation of drought in the early stages of rice variety CO 51 using PGPR isolated from the rhizosphere of xerophytes. The seeds were treated with bio inoculants and subjected to different moisture stress levels (10%, 20% and 30%) using PEG 6000. The seeds treated with bio inoculants exhibited higher germination percentage and growth traits such as shoot length root length and fresh weight, especially seeds treated with Bacillus velezensis VKSB5 (MT729963), and Bacillus altitudinis MLSB2 (MT729964) over uninoculated plants. This was found to be due to the increased proline accumulation and antioxidant activity in these seedlings, which plays a major role in drought alleviation by altering the osmotic potential and by its ROS scavenging mechanism. Hence this study provides evidence for the effective drought ameliorating ability of these cultures during the initial growth stages of rice. Further studies can contribute to the development of effective bio-inoculants for the mitigation of drought in rice.

Quantifying the Effects of Drought Using the Crop Moisture Stress as an Indicator of Maize and Sunflower Yield Reduction in Serbia

The drought in Serbia in the summer of 2017 heavily affected agricultural production, decreasing yields of maize, sunflower, soybean, and sugar beet. Monitoring moisture levels in crops can provide timely information about potential risk within a growing season, thus helping to create an early warning system for various stakeholders. The purpose of this study was to quantify the level of moisture stress in crops during summer and the consequences that it can have on yields. For that, maize and sunflower yield data provided by an agricultural company were used at specific parcels in the Backa region of Vojvodina province (Serbia) for 2017, 2018, 2019, and 2020. The crop moisture level was estimated at each parcel by calculating the normalized difference moisture index (NDMI) from Sentinel-2 data during the summer months (June–July–August). Based on the average NDMI value in July, the new crop moisture stress (CMS) index was introduced. The results showed that the CMS values at a specific parcel could be used for within-season estimation of maize and sunflower yield and the assessment of drought effects. The CMS index was tested for the current growing season of 2022 as an early warning system for yield reduction, demonstrating the potential to be included in a platform for digital agriculture, such as AgroSens, which is operational in Serbia.

Physiological Screening of Green Gram (Vigna radiata L.) Varieties by Seedling Germination Traits Under PEG Induced Drought Stress

Pulses play an important role in Indian diet due to higher protein content. Among the pulses, green gram (Vigna radiata L.) is one of the leguminous crops with high nutritional value, short growing period and soil fertility restoration by biological nitrogen fixation. Drought stress is one of the major constraints for pulse production which negatively affects its growth and production. The present experiment was performed with the objective of studying the seedling germination traits differences in five mung bean genotypes namely, MH421, VBN2, VBN4, CO8 and CO(Gg)912 under water deficit environment. It was done at laboratory conditions using various concentration of PEG 6000 as 5%, 10%, 15%, 18%, 21%. Using this level of moisture stress, 5 green gram genotypes were screened for their drought stress and the following parameters such as radicle length, shoot length, plant height, germination percentage and seed vigour were noted. By observing physiological traits of different genotypes under stress condition and founded that VBN 2 has drought tolerant ability.

Effect of Watering Schedules on Seed Germination of Two Major Agroforestry Species Dalbergia sissoo and Gmelina arborea

Aims: Water is an important natural resource supporting life and growth of plants heavily relies on water availability throughout its life cycle. Moisture stress is a major limiting factor in forest crops leading to unsuccessful seed germination. This study investigates the impact of moisture stress on the seed germination of two important agroforestry species Dalbergia sissoo and Gmelina arborea through manipulating watering schedules after sowing seeds.
 Study Design: Two independent experiments for Dalbergia sissoo and Gmelina arborea were designed in a Completely Randomized Block Design (CRBD) with six treatments and three replications for each treatment
 Place of Study: Faculty of Forestry, Birsa Agricultural University, Ranchi.
 Methodology: The complete experiment was carried inside a temporary polyhouse where the experimental materials were exposed to the six different watering schedule treatments. The first irrigation for all the treatments were started at the same time. The data recorded during the experiment were subjected to analysis of variance (ANOVA) for statistical significance and difference among treatments were determined by Duncan’s Multiple range test at (P = .05) level. 
 Results: Significant differences were observed among the treatments and the results show that with increasing level of moisture stress, the germination performance in both species is highly reduced both in terms of germination percentage and germination energy.
 Conclusion: Daily watering to the seeds can help to achieve maximum and early seed germination as evident from data of germination energy with maximum values recorded for the treatments with daily watering schedule.

Investigation of Resilience Characteristics of Unbound Granular Materials for Sustainable Pavements

In this study, a comprehensive laboratory testing program was designed to study the resilience characteristics of unbound granular materials (aggregate base coarse) using the repeated load triaxial test (RLTT). During the experimental program, the resilient modulus of unbound granular material was examined using different moisture content levels, material gradation using Fuller’s equation, and stress levels. The results show that the moisture content, material gradation, and stress level have a major influence on the resilient modulus of unbound granular materials. Furthermore, a linear model has been developed between moisture content and the resilient modulus. The model significantly predicts the change in resilient modulus by changing moisture content. The study also aimed to improve the modified Uzan model by adding the effect of moisture content. An improved modified Uzan stress moisture model has been developed, which shows a strong relationship between the resilient modulus, stress, and moisture content. This study can be used as a benchmark for validating other numerical data.