Water Stress Treatments Research Articles

Water Stress Affected Seed Accumulation of Non-reducing Soluble Sugars and Germination Performance of Three Chickpea Cultivars

Background: Water stress may alter the seed chemical composition and cause changes in the concentrations of non reducing soluble sugars in seeds and germination performance of chickpea. We evaluated the effect of water stress during chickpea seed development on seed (i) accumulation of non-reducing soluble sugars, and (ii) vigour and germination. Methods: Three chickpea cultivars (Desi-K, Saina-K and ICCV-K) were subjected to two water regimes (water stress- withholding irrigation after flowering and non-stressed- irrigation at 3-day intervals throughout the crop growth) in a completely randomized design with three replications. Seed size, viability, sugars content, solute leakage, germination percentage and mean germination time were determined from seeds harvested at physiological maturity. Result: Water stress increased the raffinose seed content of Saina-K and Desi-K, decreased the raffinose seed content in ICCV-K, but had no effect on sucrose and stachyose content. Electrical conductivity (EC) increased with water stress in all cultivars, but the increase was greater in ICCV-K (57%) compared to Desi-K (18%) and Saina-K (12%). Non-stressed seeds had larger seed size, higher seed viability and germination percentage and lower EC and mean germination time than stressed seeds. Clearly, sufficient water at seed development stage is crucial for productivity of subsequent crops as it affects seed quality. However, we recommend further studies using a wide range of water stress treatments and chickpea cultivars with different seed size, seed color and seed coat texture.

Photo-oxidative stress leading to oxylipin accumulation may trigger drought-induced leaf abscission in olive trees.

Olive trees shed their leaves under severe drought as a defence mechanism. Foliar drought-induced abscission is a programmed process occurring in a differentiated cell layer at the base of the petiole. Considering the antioxidant properties of vitamin E and its interplay with lipid peroxidation-derived jasmonates in abiotic stress responses, we hypothesized about their possible role in abscission signaling by forming a jasmonates-increasing basipetal gradient along the leaf up to the abscission zone. We exposed young olives trees to water withdrawal for 21 days, after which five leaf sections, from the apex to the petiole, were sampled on both attached and detached leaves of irrigated and water-stressed trees. We found that prolonged drought stress resulted in a sharp reduction in the photosystem II efficiency, chlorophyll and vitamin E contents in leaves, leading to photo-oxidative stress, reflected by the increase in lipid peroxidation. In addition, the content of chloroplast-derived oxylipins and phytohormones, such as jasmonoyl-isoleucine and salicylic acid, increased. At the same time, α-tocopherol decreased in the petiole of water-stressed attached leaves, suggesting a conditioning for the abscission process to occur. Although no differences were observed in petioles from attached and detached leaves, the dropped ones showed higher oxidative stress in the leaf blade. It is concluded that redox signaling through oxylipins accumulation may trigger leaf abscission in drought-stressed olive trees. Mechanical stress is, however, additionally needed to execute leaf abscission once the abscission zone is properly conditioned. This article is protected by copyright. All rights reserved.

Effects of water stress on starch synthesis and accumulation of two rice cultivars at different growth stages.

Rice is a water intensive crop and soil water conditions affect rice yield and quality. However, there is limited research on the starch synthesis and accumulation of rice under different soil water conditions at different growth stages. Thus, a pot experiment was conducted to explore the effects of IR72 (indica) and Nanjing (NJ) 9108 (japonica) rice cultivars under flood-irrigated treatment (CK, 0 kPa), light water stress treatment (L, -20 ± 5 kPa), moderate water stress treatment (M, -40 ± 5 kPa) and severe water stress treatment (S, -60 ± 5 kPa) on the starch synthesis and accumulation and rice yield at booting stage (T1), flowering stage (T2) and filling stage (T3), respectively. Under LT treatment, the total soluble sugar and sucrose contents of both cultivars decreased while the amylose and total starch contents increased. Starch synthesis-related enzyme activities and their peak activities at mid-late growth stage increased as well. However, applying MT and ST treatments produced the opposite effects. The 1000-grain weight of both cultivars increased under LT treatment while the seed setting rate increased only under LT3 treatment. Compared with CK, water stress at booting stage decreased grain yield. The principal component analysis (PCA) showed that LT3 got the highest comprehensive score while ST1 got lowest for both cultivars. Furthermore, the comprehensive score of both cultivars under the same water stress treatment followed the trend of T3 > T2 > T1, and NJ 9108 had a better drought-resistant ability than IR72. Compared with CK, the grain yield under LT3 increased by 11.59% for IR72 and 16.01% for NJ 9108, respectively. Overall, these results suggested that light water stress at filling stage could be an effective method to enhance starch synthesis-related enzyme activities, promote starch synthesis and accumulation and increase grain yield.

Influence of Silicon on Tolerance to Water Deficit of Peach Trees

Water deficit in young fruit trees can reduce growth and future orchard productivity. Exogenous silicon (Si) applications have been associated with induced resistance to biotic and abiotic stresses such as water deficit, but the role of Si in fruit trees is still largely unexplored. The aim of the study was to evaluate the effect of Si applications on water status and gas exchange of young peach trees. This study comprises two experiments arranged in a factorial design with two water regimens (well-irrigated or water-stressed) and three Si concentrations (0, 10, or 20 mg⋅L−1 in the first experiment; 0, 20, or 40 mg⋅L−1 in the second experiment). Si applications via foliar spray were performed weekly after the water regimens were clearly established. Tree water status (midday stem water potential), and gas exchange parameters (CO2 assimilation, leaf transpiration, stomatal conductance, leaf water use efficiency) were measured. Si application at 10 or 20 mg⋅L−1 improved water status of water-stressed trees without affecting gas exchange, but 40 mg⋅L−1 reduced CO2 assimilation. Thus, foliar applications of Si could be a promising strategy for nonirrigated, nonbearing orchards to maintain their water status during dry periods and/or improve their recovery from water deficit.

Effect of Water Deficit on Germination, Growth and Biochemical Responses of Four Potentially Invasive Ornamental Grass Species

Ornamental plant species introduced into new environments can exhibit an invasive potential and adaptability to abiotic stress factors. In this study, the drought stress responses of four potentially invasive ornamental grass species (Cymbopogon citratus, Cortaderia selloana, Pennisetum alopecuroides and P. setaceum) were analysed. Several seed germination parameters were determined under increasing polyethylene glycol (PEG 6000) concentrations. Additionally, plants in the vegetative stage were subjected to intermediate and severe water stress treatments for four weeks. All species registered high germination rates in control conditions (no stress treatment), even at high PEG concentrations, except C. citratus, which did not germinate at -1 MPa osmotic potential. Upon applying the water stress treatments, P. alopecuroides plants showed the highest tolerance, and C. citratus appeared the most susceptible to drought. Stress-induced changes in several biochemical markers (photosynthetic pigments, osmolytes, antioxidant compounds, root and shoot Na+ and K+ contents), highlighted different responses depending on the species and the stress treatments. Basically, drought tolerance seems to depend to a large extent on the active transport of Na+ and K+ cations to the aerial part of the plants, contributing to osmotic adjustment in all four species and, in the case of the most tolerant P. alopecuroides, on the increasing root K+ concentration under water deficit conditions. The study shows the invasive potential of all species, except C. citratus, in dry areas such as the Mediterranean region, especially in the current climate change scenario. Particular attention should be given to P. alopecuroides, which is widely commercialised in Europe as ornamental.

Effect of Different Priming Methods on Seed Viability and Seedling Growth of Upland Rice under Drought Stress

This study aims to determine the effect of different priming methods on the viability and early growth of upland rice under drought stress. Priming is an important approach to improve the resistance of upland rice plants to drought stress from the germination phase to growth, especially on sub-optimal land. There are several efficient priming methods as seed pretreatment to increase germination and tolerance to drought stress. An effective priming method is needed to increase the germination and growth of upland rice seedlings for application in dryland agriculture. Therefore, an experiment was conducted at the Seed laboratory of Pangkep State Polytechnic of Agriculture, Indonesia, from September to October of 2022 to investigate the effect of several priming methods on the germination and growth of upland rice seedlings under drought stress. The experiment consisted of 2 stages, germination testing and seedling growth phase testing with the addition of water stress treatment. Experiment 1 was conducted in a completely randomized design (CRD) with four replications, including Control (no priming), Osmopriming with 15% and 20% PEG solution, Redox Priming with 3% and 6% H2O2 solution, and Organic Priming using 50% and 75% Moringa leaf extract. Experiment 2 was conducted using a two-factor of factorial in Randomized Block design (RBD) with three replications. The first factor is the Seedling results of stage 1 experiments (selected the best of each priming method) includes 4 treatments each Control treatment, Osmopriming with 15% PEG solution, Redox Priming with 3% H2O2 solution, and Organic Priming with 50% Moringa Leaf Extract. The second factor is the level of Drought Stress conducted by 100%, 60%, and 30% of Field Capacity. The results showed that the priming method with Osmopriming 15% PEG solution gave the best results on Seed germination percentage (87.5%) followed by Organic priming with 50% Moringa Leaf Extract (SGP 85%). Under drought stress conditions with 30% field capacity, the highest increase in proline levels was observed with H2O2 redox priming 3% (10.3 µ-mol. g-1 ), while the average root growth of all primed seedlings showed better root growth than seeds without priming treatment. Seed priming gives better results on the growth and physiological activities of upland rice at several levels of drought stress, in the early growth phase of seedlings

The Effects of Meteorological Factors on Grain Yield of Foxtail Millet (Setaria italica Beauv.) under Different Water Supply Conditions

Meteorological factors have significant impacts on crop yield. To account for the impact of meteorological factors on foxtail millet (Setaria italica Beauv.) production in different water conditions, a total of 38 collected varieties were grown in nine seasons from 2011 to 2020 (except 2016) under well-watered (WW) and water-stressed (WS) conditions. The results showed that there was a large seasonal variation in GY; the variation ranged from 4.92 t ha−1 to 6.95 t ha−1 under the WW treatment and from 3.50 t ha−1 to 5.77 t ha−1 under the WS treatment. The impacts of meteorological factors on foxtail millet under the WW and WS treatments were different; sunshine duration during the whole stage, vegetative stage and reproductive stage had the greatest impact under the WW treatment, while under the WS treatment, sunshine duration and the diurnal temperature range during the whole stage and reproductive stage were the greatest impact factors on grain yield. This work could help us in high-yield foxtail millet cultivation and breeding.

A river basin spatial model to quantitively advance understanding of riverine tree response dynamics to water availability and hydrological management

Ecological condition continues to decline in arid and semi-arid river basins globally due to hydrological over-abstraction combined with changing climatic conditions. Whilst provision of water for the environment has been a primary approach to alleviate ecological decline, how to accurately monitor changes in riverine trees at fine spatial and temporal scales, remains a substantial challenge. This is further complicated by constantly changing water availability across expansive river basins with varying climatic zones. Within, we combine rare, fine-scale, high frequency temporal in-situ field collected data with machine learning and remote sensing, to provide a robust model that enables broadscale monitoring of physiological tree water stress response to environmental changes via actual evapotranspiration (ET). Physiological variation of Eucalyptus camaldulensis (River Red Gum) and E. largiflorens (Black Box) trees across 10 study locations in the southern Murray-Darling Basin, Australia, was captured instantaneously using sap flow sensors, substantially reducing tree response lags encountered by monitoring visual canopy changes. Actual ET measurement of both species was used to bias correct a national spatial ET product where a Random Forest model was trained using continuous timeseries of in-situ data of up to four years. Precise monthly AMLETT (Australia-wide Machine Learning ET for Trees) ET outputs in 30 m pixel resolution from 2012 to 2021, were derived by incorporating additional remote sensing layers such as soil moisture, land surface temperature, radiation and EVI and NDVI in the Random Forest model. Landsat and Sentinal-2 correlation results between in-situ ET and AMLETT ET returned R2 of 0.94 (RMSE 6.63 mm period−1) and 0.92 (RMSE 6.89 mm period−1), respectively. In comparison, correlation between in-situ ET and a national ET product returned R2 of 0.44 (RMSE 34.08 mm period−1) highlighting the need for bias correction to generate accurate absolute ET values. The AMLETT method presented here, enhances environmental management in river basins worldwide. Such robust broadscale monitoring can inform water accounting and importantly, assist decisions on where to prioritize water for the environment to restore and protect key ecological assets and preserve floodplain and riparian ecological function.

Hyperspectral monitoring on proline content in winter wheat under water stress

Frequent occurrence of drought disaster will seriously affect the growth and development of winter wheat (Triticum aestivum). We set different water stress treatments (80%, 60%, 45%, 35%, 30% of field water capacity) to simulate the severity of drought disaster. We measured free proline content (Pro) of winter wheat, and investigated the responses of Pro to canopy spectral reflectance under water stress. Three methods, i.e., correlation analysis and stepwise multiple linear regression (CA+SMLR), partial least squares and stepwise multiple linear regression (PLS+SMLR), and successive projections algorithm (SPA) were used to extract the hyperspectral cha-racteristic region and characteristic band of proline. Furthermore, partial least square regression (PLSR) and multiple linear regression (MLR) methods were used to establish the predicted models. The results showed that Pro content of winter wheat was higher under water stress, and that the spectral reflectance of canopy changed regularly in different bands, indicating that Pro content of winter wheat was sensitive to water stress. The content of Pro was highly correlated with the red edge of canopy spectral reflectance, with the 754, 756 and 761 nm bands being sensitive to Pro change. The PLSR model performed good, followed by the MLR model, both showing good predictive ability and high model accuracy. In general, it was feasible to monitor Pro content of winter wheat by hyperspectral technique.

Targeted water stress treatments and the anti-tyrosinase activity of Greyia radlkoferi

Targeted water stress treatments and the anti-tyrosinase activity of <i>Greyia radlkoferi</i>

Cyclopia subternata growth, yield, proline and relative water content in response to water deficit stress

Cyclopia, generally known as honeybush, and belonging to the Fabaceae family, originates from the Cape Floristic Region of the Eastern Cape and Western Cape provinces of South Africa. Currently, 6 honeybush species are commercially cultivated but, to date, there have been limited trials attempting to study their agronomic water demand. A pot trial was conducted where Cyclopia subternata plants were cultivated on different soil types (Stellenbosch granite, Stellenbosch shale and Stellenbosch clovelly) and subjected to three different water-deficit stress levels (well-watered, semi-stressed and stressed). Remarkably, irrigation treatments and soil types did not significantly affect the growth of the plants. However, the well-watered treatment consistently had higher yields compared to the other two treatments. The water-stressed (semi-stressed and stressed) treatments had lower relative water contents (RWC) with higher concentrations of proline, which signify water stress, compared to the control treatment. Higher proline and lower RWC contents found in this study are indications of water stress.

Provenance influences seed germination and phenotypic responses to water restriction in the endemic Beilschmiedia miersii (Gay) Kosterm

The higher drought intensity recorded in the last decades in the Mediterranean zone of Chile increased the level of threats of the endemic Beilschmiedia miersii (Gay) Kosterm and has raised concern about its capacity to face drought. In this study, we assessed the effect of seed provenance and mother tree on seed germination traits, seedling growth, biomass allocation, presence of cotyledons, and survival responses of B. miersii cultivated under two water treatments (well-watered versus water stress. Average pre-dawn plant water potentials of −0.9 and −4.5 MPa, respectively). The germination stage of this trial showed significant differences in germination capacity, germination energy, and the maximum value of Czabator. Provenances from the southern range of the species, with higher precipitation (Cantillana and El Arbol) had a better germination performance, however, once germinated, the ability of the seedlings to survive in the nursery was high only in two of the five provenances under study. The coastal and interior provenances with lower precipitations (El Pobre, Longotoma, and Antumapu) were not able to survive to the seedling stage (&amp;lt;5% survival). Seedling growth and survival varied significantly between the two remaining provenances and the two watering treatments. The provenance El Arbol, exhibited a higher survival, growth, presence of cotyledons, and biomass traits. This provenance also exhibited a higher presence of cotyledons in both watering treatments and an unaltered root to shoot ratio between the well-watered and the water stress treatments. Our results suggests that there is important phenotypic variation for seed germination and seedling survival associated to the provenance origin, emphasizing the importance of a nursery-evaluation phase before the beginning of restoration projects at the landscape level.

Effect of Post-Drought Rehydration on Winter Wheat Fluorescence and Photosynthetic Indices under Different Levels of Nitrogen Application

Studying the response of winter wheat to post-drought rehydration is conducive to understanding the efficient utilization of water-saving technology, such as regulating deficit irrigation and increasing water use efficiency. The controlled condition experiment in the rain shelter was conducted in 2020. The two water stress treatments, including post-drought rehydration at the jointing and heading stages, were combined with high nitrogen (N) (250 kg/hm2), low N (125 kg/hm2), and no N (0 kg/hm2, control). The effects of post-drought rehydration on the relative chlorophyll content (SPAD), major fluorescence parameters, and photosynthetic indexes of winter wheat were determined. The results showed that post-drought rehydration increased the SPAD value, the efficiency of light energy conversion, maximum potential photo-electron transport, and the photosynthetic indices and decreased the photochemical quenching coefficient. Among them, the compensatory effect of rehydration at the heading stage on SPAD, fluorescence parameters, and photosynthetic indexes was more significant (p &lt; 0.05), and the winter wheat needed a recovery process after rehydration. Increased application of N fertilizer can alleviate the effects of water stress on the fluorescence parameters and photosynthetic properties of flag leaf and promote the degree of the response of fluorescence parameters and photosynthetic properties to rehydration. The specific effects were as follows: high N &gt; low N &gt; no N application. As a result, winter wheat had a certain compensatory effect of rehydration after timely drought stress; the compensatory effect of rehydration could be enhanced under the condition of increasing N application.

Iris lactea var. chinensis plant drought tolerance depends on the response of proline metabolism, transcription factors, transporters and the ROS-scavenging system

BackgroundIris lactea var. chinensis, a perennial herbaceous species, is widely distributed and has good drought tolerance traits. However, there is little information in public databases concerning this herb, so it is difficult to understand the mechanism underlying its drought tolerance.ResultsIn this study, we used Illumina sequencing technology to conduct an RNA sequencing (RNA-seq) analysis of I. lactea var. chinensis plants under water-stressed conditions and rehydration to explore the potential mechanisms involved in plant drought tolerance. The resulting de novo assembled transcriptome revealed 126,979 unigenes, of which 44,247 were successfully annotated. Among these, 1187 differentially expressed genes (DEGs) were identified from a comparison of the water-stressed treatment and the control (CK) treatment (T/CK); there were 481 upregulated genes and 706 downregulated genes. Additionally, 275 DEGs were identified in the comparison of the rehydration treatment and the water-stressed treatment (R/T). Based on Quantitative Real-time Polymerase Chain Reaction (qRT-PCR) analysis, the expression levels of eight randomly selected unigenes were consistent with the transcriptomic data under water-stressed and rehydration treatment, as well as in the CK. According to Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, proline metabolism-related DEGs, including those involved in the ‘proline catabolic process’, the ‘proline metabolic process’, and ‘arginine and proline metabolism’, may play important roles in plant drought tolerance. Additionally, these DEGs encoded 43 transcription factors (TFs), 46 transporters, and 22 reactive oxygen species (ROS)-scavenging system-related proteins. Biochemical analysis and histochemical detection showed that proline and ROS were accumulated under water-stressed conditions, which is consistent with the result of the transcriptomic analysis.ConclusionsIn summary, our transcriptomic data revealed that the drought tolerance of I. lactea var. chinensis depends on proline metabolism, the action of TFs and transporters, and a strong ROS-scavenging system. The related genes found in this study could help us understand the mechanisms underlying the drought tolerance of I. lactea var. chinensis.

Physiological strategies for handling summer water stress differ among co-existing species and between juvenile and mature trees

Determining tree response to climate stress is critical for predicting changes in forest carbon dynamics as well as tree mortality. In temperate deciduous forests, describing this response is complicated by the complex diversity of leaf and wood characteristics among co-existing species. Furthermore, because of the inherent logistical limitations of measuring mature forest trees, many carbon models and stress-response studies are informed by physiological data collected from juvenile trees (seedlings or saplings). However, the extent to which juvenile and mature trees differ in their physiological responses to water stress is not well documented under natural conditions. The majority of carbon sequestered in a forest is in mature trees; therefore, direct canopy measurements comparing responses to climate in juvenile and mature trees would allow us to more accurately predict changes in ecosystem carbon uptake. Here, we present data describing the physiological responses to summer water stress in juvenile trees of six temperate deciduous species. Our results indicate that species exhibited variation and plasticity in stress hydraulic parameters yet maintained similar rates of carbon uptake. We demonstrate how integrative photosynthetic parameters, such as photosynthetic capacity and quantum efficiency of photosystem II, are beneficial for wholistically displaying physiological responses at the leaf level. We further compared seasonal patterns of leaf water potential during decreasing soil water availability between the juvenile trees and co-existing mature trees of the same species. Our data reveal that while some species remain static in their hydraulic behavior from the juvenile to adult stage, other species are dynamic between life stages. Models, as well as experimental studies examining tree response to stressors, should plan for plasticity in physiological parameters among co-existing species, and should further allow variability between life stages for particular species. The capacity to effectively inform models from data collected in mature trees will inevitably lead to improved predictions of tree mortality and forest carbon trajectories.

Effect of Recurrent Salt and Drought Stress Treatments on the Endangered Halophyte Limonium angustebracteatum Erben

Limonium angustebracteatum is an endemic halophyte from the Spanish Mediterranean coastal salt marshes. To investigate this species' ability to cope with recurrent drought and salt stress, one-year-old plants were subjected to two salt stress treatments (watering with 0.5 and 1 M NaCl solutions), one water stress treatment (complete irrigation withholding), or watered with non-saline water for the control, across three phases: first stress (30 days), recovery from both stresses (15 days), and second stress (15 days). Growth and biochemical parameters were determined after each period. The plants showed high salt tolerance but were sensitive to water deficit, as shown by the decrease in leaf fresh weight and water content, root water content, and photosynthetic pigments levels in response to the first water stress; then, they were restored to the respective control values upon recovery. Salt tolerance was partly based on the accumulation of Na+, Cl- and Ca2+ in the roots and predominantly in the leaves; ion levels also decreased to control values during recovery. Organic osmolytes (proline and total soluble sugars), oxidative stress markers (malondialdehyde and H2O2), and antioxidant compounds (total phenolic compounds and flavonoids) increased by various degrees under the first salt and water stress treatments, and declined after recovery. The analysed variables increased again, but generally to a lesser extent, during the second stress phase, suggesting the occurrence of stress acclimation acquired by the activation of defence mechanisms during the first stress period.

Study on the Yield and Yield Contributing Characters of Aus Rice Varieties in Various Soil Moisture Levels

The experiment was conducted at the Plant Physiology Laboratory (central laboratory) and Shade house of Field Laboratory of Agricultural Botany Department, Sher-e-Bangla Agricultural University, Dhaka, Bangladesh under a field experiment was also carried out on yield contributing parameters. There were three rice genotypes namely BRRI dhan55 (V1), BR6976-2B-15 (V2) and tolerant check Hashikalmi (V3) and seven water stress were imposed as treatments. The treatments were arranged for 0 days of water stress (control) irrigated continuously throughout the experimental period (T0). When the seedlings were 20 days old, water deficit was imposed for seven days (T1), when the seedlings were 35 days old, water deficit was imposed for seven days (T2), when the seedlings were 55 days old, water deficit was imposed for seven days (T3), when the seedlings were 75 days old, water deficit was imposed for seven days (T4). When the seedlings were 95 days old, water deficit was imposed for seven days (T5) and when the seedlings were 115 days old, water deficit was imposed for seven days (T6). BRRI dhan55 and Hashikalmi produced the highest tillers, grains, number of spikelets and yield. The grain sterility percentage is much higher in BR6976-2B-15 due to water stress treatment compared to other genotypes. Grain yield was the highest in BRRI dhan55 and Hashikalmi and gradually decreased with increased water stress treatment compared to other genotypes. Decreased grain yield per plant under water stress treatment reduction of tillers, panicle, filled grains, root, shoot, spikelet/panicle, panicle dry matter content, and with other causes. The harvest index was decreased due to water stress conditions in all the genotypes while less affected in BRRI dhan55 and Hashikalmi.

Os efeitos de diferentes aplicações de filmes de partículas em amendoeiras

ABSTRACT: Particle film applications have become common in agriculture today given the understanding of the effects of limiting high temperatures and solar radiation on plant physiology. This study was conducted to compare the effects of different particle materials on some physiological and fruit quality attributes of almonds. To achieve this, two non-transparent white solid and three transparent aqueous particle film materials were applied by foliar spraying on deficit irrigated almond trees (cv. Ferragnes). Membrane injury (MI), relative water content (RWC), the SPAD chlorophyll index, leaf temperature and some macro- and micro-nutrient contents were examined in addition to fruit sizes, weights, total oils and fatty acid compositions. The applied treatments significantly influenced the evaluated parameters, which indicated reduced stress and improved fruit quality. MI was found to be from 42.8 to 73.9%, RWC varied from 76.8 to 92.9%, and the K/Na ratio ranged between 103.3 and 521.0. As a result of this study, it was concluded that the observed improvements were due to the effects of the evaluated materials and that particle film applications can be beneficial in alleviating heat, light and water stress in almond trees.

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

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

Identifying Drought-Tolerant Impatiens Genotypes by Using Water Stress Treatment

The drought-tolerant Impatiens genotypes are known for their resistance to limited or stressed water. The study aimed to identify drought-tolerance of Impatiens clones. The experiment used a split-plot design replicated three times, with the water stress treatment as the main plot and Impatiens clones as subplots. The main plot consists of 100% and 60% of field capacity. The subplots consist of five Impatiens clones, 17.12; 12; 33.3; 40 B and Impatiens cv of Impala Agrihorti as a control. The results showed that 60% field capacity decreased morphological and physiological traits. Still, the drought-tolerant clones were less affected by the stress and produced more flowers than the others. The most drought-tolerant Impatiens was clone 12. The mechanism of drought tolerance Impatiens was by stomatal closure when the humidity in the growing medium was decreasing. The stomata closure did not significantly reduce the fresh and dry weight in drought-tolerant plants, but it affected the delay in flower initiation. The plant accumulated assimilate for plant height and diameter growth but is not sufficient for generative initiation. They assimilate in the vegetative phase and can be used as sources for flower formation, which show no significant decrease in the number of flowers. The study implies that the drought-tolerant Impatiens clones can be used as genotype sources for drought-tolerant or can be released as new varieties of Impatiens for landscape plants with the superiority in having drought tolerant.