Physiological Mechanism of Drought-Resistant Rice Coping with Drought Stress

Abstract Drought stress is one of major threats to rice production. The weakening of leaf photosynthesis due to drought is the main reason for the reduction of grain yield, but its mechanism is still obscure. The objectives of this study were to reveal the physiological mechanism of drought stress affecting photosynthetic capacity and grain yield. Pot experiments were conducted with three rice cultivars, Hanyou113 (HY113), Huanghuazhan (HHZ) and Zhonghan3 (ZH3) under four water management treatments (traditional flooding (CK), mild drought stress (LD), moderate drought stress (MD) and severe drought stress (HD)) in 2013 and 2014. Compared with CK, grain yield was significantly reduced by 14.9%, 30.8% and 12.8% in HY113, HHZ and ZH3 under mild drought stress, 32.9%, 33.7% and 22.9% in HY113, HHZ and ZH3 under moderate drought stress and 53.6%, 45.6% and 30.7% in HY113, HHZ and ZH3 under severe drought stress, respectively. The photosynthetic rate (Pn) decreased by 49.0% from 20.0 to 10.2 µmol m-2 s-1 in HY113, and 67.6% from 23.4 to 7.58 µmol m-2 s-1 in HHZ, and 39.3% from 23.4 to 14.2 in ZH3. The Pn of HHZ was similar to that of ZH3 under CK conditions. The yield reduction of drought-resistant cultivars was smaller than that of conventional cultivars. Maintaining leaf water potentia (LWP), Pn, photosystem II (PSII) original light energy conversion efficiency, non–photochemical quenching coefficient (NPQ), and increasing in the ratio of photochemical reaction energy in fluorescence and antioxidant enzyme activity, is the physiological basis to achieve a relatively high photosynthesis. These traits could be the target for breeder to developing drought-tolerant varieties.

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Phedimus Aizoon L. Responds to Drought Stress: Growth, Physiological Changes and Mechanism of Drought Resistance

10.21203/rs.3.rs-132688/v1 ◽

2020 ◽

Author(s):

Yuhang Liu ◽

Zhongqun He ◽

Yongdong Xie ◽

Lihong Su ◽

Ruijie Zhang ◽

...

Keyword(s):

Drought Stress ◽

Drought Resistance ◽

Soluble Sugar ◽

Severe Drought ◽

Physiological Changes ◽

Moderate Drought ◽

Negative Effect ◽

Mda Content ◽

Maximum Water ◽

Mild Drought

Abstract A pot experiment was conducted to investigate the growth, physiological changes and mechanism of drought resistance of Phedimus aizoon L. under different levels of water content .CK: 75% ~ 80% of the MWHC (maximum water holding capacity), Mild drought: 55% ~ 60%, Moderate drought: 40% ~ 45%, Severe drought: 20% ~ 25%.We observed that the plants grew normally in the first two treatments, even the mild drought promoted the growth of the roots. In the last two treatments, drought stress had a significant negative effect on plant growth, at the same time, Phedimus aizoon L. also made positive physiological response to cope with the drought: The aboveground part of the plant (leaf, plant height, stem diameter) was smaller, the waxy layer of the leaves was thickened, the stomata of the leaves were closed during the day, and only a few stomata were opened at night, which proved that the dark reaction cycle metabolism mode of the plant was transformed from C3 cycle to CAM pathway. The activity of antioxidant enzymes (SOD, POD and CAT) was continuously increased to alleviate the damage caused by drought. To ensure the relative stability of osmotic potential, the contents of osmoregulation substances such as proline, soluble sugar, soluble protein and trehalose increased correspondingly. But plants have limited regulatory power, with aggravation of drought stress degree and extension of stress time, the MDA content and electrolyte leakage of leaves increased continuously. Observed under electron microscope,the morphology of chloroplast and mitochondria changed and the membrane structure was destroyed. The plant's photosynthetic and respiratory mechanisms are destroyed and the plant gradually die.

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Exogenous salicylic acid-induced drought stress tolerance in wheat (Triticum aestivum L.) grown under hydroponic culture

PLoS ONE ◽

10.1371/journal.pone.0260556 ◽

2021 ◽

Vol 16 (12) ◽

pp. e0260556

Author(s):

Ali Ahmad ◽

Zubair Aslam ◽

Maliha Naz ◽

Sadam Hussain ◽

Talha Javed ◽

...

Keyword(s):

Salicylic Acid ◽

Drought Stress ◽

Root Length ◽

Shoot Length ◽

Water Deficit Stress ◽

Wheat Crop ◽

Severe Drought ◽

Drought Condition ◽

Moderate Drought ◽

Mild Drought

Wheat is an important cereal crop, which is adversely affected by water deficit stress. The effect of induced stress can be reduced by the application of salicylic acid (SA). With the objective to combat drought stress in wheat, an experiment was conducted in greenhouse under hydroponic conditions. The treatments consisted of (a) no drought (DD0 = 0 MPa), mild drought (DD1 = -0.40 MPa) and severe drought (DD2 = -0.60 MPa) by applying PEG-8000, (b) two contrasting wheat varieties Barani-17 (drought tolerant) and Anaj-17 (drought-sensitive), and (c) foliar treatments of salicylic acid (0, 50 mM, 75 mM, and 100 mM). Evaluation of wheat plants regarding biochemical, physiological, and morphological attributes were rendered after harvesting of plants. Statistically, maximum shoot and root fresh and dry weights (18.77, 11.15 and 1.99, 1.81 g, respectively) were recorded in cultivar Barani-17 under no drought condition with the application of SA (100 mM). While, minimum shoot and root fresh and dry weights (6.65, 3.14 and 0.73, 0.61 g, respectively) were recorded in cultivar Anaj-2017 under mild drought stress without SA application. The maximum shoot length (68.0 cm) was observed in cultivar Barani-2017 under no drought condition with the application of SA (100 mM). While, maximum root length (59.67 cm) was recorded in cultivar Anaj-17 under moderate drought stress without application of SA. Further, minimum shoot length (28.67 cm) was recorded in Anaj-17 under moderate drought stress without SA application. Minimum root length (38.67 cm) was recorded in cultivar Barani-17 under no drought condition without SA application. Furthermore, maximum physio-biochemical traits, including membrane stability index (MSI), chlorophyl content, photosynthetic rates, stomatal conductance, antioxidant enzymatic activities and relative water content (RWC) were found highest in cultivar Barani-17 under no drought stress and SA application at 100 mM. However, minimum values of these traits were recorded in cultivar Anaj-17 under severe drought stress without SA application. Our results also demonstrated that under severe drought, application of SA at 100 mM significantly increased leaf nitrogen (N), phosphrus (P) and potassium (K) contents and cultivar Barani-17 demonstrated significantly higher values than Anaj-17. The obtained results also indicated that the cultivation of wheat under drought stress conditions noticeably declines the morphological, physiological, and biochemical attributes of the plants. However, the exogenous application of SA had a positive impact on wheat crop for enhancing its productivity.

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The Effect of Different Drought Stress on Antioxidant Enzymes and Lipid Peroxidation on Zoysia japonica

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.518-523.5489 ◽

2012 ◽

Vol 518-523 ◽

pp. 5489-5492

Author(s):

Zhong Lin Chen ◽

Su Nan Xu ◽

Yue Li ◽

Shi Xie ◽

Li Xia Fan ◽

...

Keyword(s):

Lipid Peroxidation ◽

Drought Stress ◽

Field Capacity ◽

Guaiacol Peroxidase ◽

Severe Drought ◽

Zoysia Japonica ◽

Sod Activity ◽

Moderate Drought ◽

Mda Content ◽

Mild Drought

The objective of this study was to understand the effects of mild, moderate and severe drought stress on zoysiagrass(Zoysia japonica). Superoxide dismutase (SOD), guaiacol peroxidase (POD), catalase (CAT), and malondialdehyde (MDA) content were investigated. Mild drought(60%-70% of field capacity), moderate drought(45%-55% of field capacity), and severe drought (25%-35% of field capacity) were remained for 16 days. A gradual increase was observed in SOD activity of Zoysiagrass from 1 to13 days of drought stress in all treatments. POD and CAT activity, and lipid peroxidation increased in all treatments, and maximum change was happened in severe drought group. Severe drought has more serious damage to Zoysia japonica than mild drought and moderate drough. This suggests that Zoysiagrass has excellent drought tolerance and its ability to survive in the drought environment is very strong.

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Drought resistance mechanisms of Phedimus aizoon L.

Scientific Reports ◽

10.1038/s41598-021-93118-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Yuhang Liu ◽

Zhongqun He ◽

Yongdong Xie ◽

Lihong Su ◽

Ruijie Zhang ◽

...

Keyword(s):

Drought Stress ◽

Soluble Sugars ◽

Resistance Mechanisms ◽

Severe Drought ◽

Available Water Content ◽

Drought Tolerant ◽

Moderate Drought ◽

Leaf Anatomical Structure ◽

Physiological Indexes ◽

Mild Drought

AbstractPhedimus aizoon L. is a drought-resistant Chinese herbal medicine and vegetable. However, its drought tolerant limit and the mechanism of drought tolerance are unknown, which restricts the promotion of water-saving cultivation of Phedimus aizoon L. in arid areas. To solve the above problem, we carried out a 30-day-long drought stress experiment in pots that presented different soil water contents and were divided into four groups: control check, 75–80% of the maximum water-holding capacity (MWHC); mild drought, 55–60%; moderate drought, 40–45%; and severe drought, 20–25%. The dynamic changes in both plant physiological indexes from 10 to 30 days and leaf anatomical structure on the 30th day of stress were recorded. The results show that Phedimus aizoon L. grew normally under mild drought stress for 30 days, but the growth of the plants became inhibited after 20 days of severe drought and after 30 days of moderate drought. At the same time, Phedimus aizoon L. physiologically responded to cope with drought stress: the growth of the root system accelerated, the waxy layer of the leaves thickened, and the dark reactions of the plants transformed from those of the C3 cycle to CAM. The activity of antioxidant enzymes (SOD, POD and CAT) continuously increased to alleviate the damage caused by drought stress. To ensure the relative stability of the osmotic potential, the contents of osmoregulatory substances such as proline, soluble sugars, soluble protein and trehalose increased correspondingly. Although Phedimus aizoon L. has strong drought stress resistance, our experimental results show that the soil available water content should not be less than 27% during cultivation.

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Enhancement of drought tolerance in diverse Vicia faba cultivars by inoculation with plant growth-promoting rhizobacteria under newly reclaimed soil conditions

Scientific Reports ◽

10.1038/s41598-021-02847-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Elsayed Mansour ◽

Hany A. M. Mahgoub ◽

Samir A. Mahgoub ◽

El-Sayed E. A. El-Sobky ◽

Mohamed I. Abdul-Hamid ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Plant Growth ◽

Plant Growth Promoting Rhizobacteria ◽

Severe Drought ◽

Drought Conditions ◽

Moderate Drought ◽

Plant Growth Promoting ◽

Growth Promoting ◽

Effects Of Drought

AbstractWater deficit has devastating impacts on legume production, particularly with the current abrupt climate changes in arid environments. The application of plant growth-promoting rhizobacteria (PGPR) is an effective approach for producing natural nitrogen and attenuating the detrimental effects of drought stress. This study investigated the influence of inoculation with the PGPR Rhizobium leguminosarum biovar viciae (USDA 2435) and Pseudomonas putida (RA MTCC5279) solely or in combination on the physio-biochemical and agronomic traits of five diverse Vicia faba cultivars under well-watered (100% crop evapotranspiration [ETc]), moderate drought (75% ETc), and severe drought (50% ETc) conditions in newly reclaimed poor-fertility sandy soil. Drought stress substantially reduced the expression of photosynthetic pigments and water relation parameters. In contrast, antioxidant enzyme activities and osmoprotectants were considerably increased in plants under drought stress compared with those in well-watered plants. These adverse effects of drought stress reduced crop water productivity (CWP) and seed yield‐related traits. However, the application of PGPR, particularly a consortium of both strains, improved these parameters and increased seed yield and CWP. The evaluated cultivars displayed varied tolerance to drought stress: Giza-843 and Giza-716 had the highest tolerance under well-watered and moderate drought conditions, whereas Giza-843 and Sakha-4 were more tolerant under severe drought conditions. Thus, co-inoculation of drought-tolerant cultivars with R. leguminosarum and P. putida enhanced their tolerance and increased their yield and CWP under water-deficit stress conditions. This study showed for the first time that the combined use of R. leguminosarum and P. putida is a promising and ecofriendly strategy for increasing drought tolerance in legume crops.

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Assessment of Genetic Diversity for Drought, Heat and Combined Drought and Heat Stress Tolerance in Early Maturing Maize Landraces

Plants ◽

10.3390/plants8110518 ◽

2019 ◽

Vol 8 (11) ◽

pp. 518 ◽

Cited By ~ 7

Author(s):

Nelimor ◽

Badu-Apraku ◽

Tetteh ◽

N’guetta

Keyword(s):

Climate Change ◽

Heat Stress ◽

Drought Stress ◽

Grain Yield ◽

Yield Potential ◽

Yield Reduction ◽

International Institute ◽

Improvement Program ◽

Maize Varieties ◽

Drought And Heat Stress

Climate change is expected to aggravate the effects of drought, heat and combined drought and heat stresses. An important step in developing ‘climate smart’ maize varieties is to identify germplasm with good levels of tolerance to the abiotic stresses. The primary objective of this study was to identify landraces with combined high yield potential and desirable secondary traits under drought, heat and combined drought and heat stresses. Thirty-three landraces from Burkina Faso (6), Ghana (6) and Togo (21), and three drought-tolerant populations/varieties from the Maize Improvement Program at the International Institute of Tropical Agriculture were evaluated under three conditions, namely managed drought stress, heat stress and combined drought and heat stress, with optimal growing conditions as control, for two years. The phenotypic and genetic correlations between grain yield of the different treatments were very weak, suggesting the presence of independent genetic control of yield to these stresses. However, grain yield under heat and combined drought and heat stresses were highly and positively correlated, indicating that heat-tolerant genotypes would most likely tolerate combined drought and stress. Yield reduction averaged 46% under managed drought stress, 55% under heat stress, and 66% under combined drought and heat stress, which reflected hypo-additive effect of drought and heat stress on grain yield of the maize accessions. Accession GH-3505 was highly tolerant to drought, while GH-4859 and TZm-1353 were tolerant to the three stresses. These landrace accessions can be invaluable sources of genes/alleles for breeding for adaptation of maize to climate change.

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Water Deficit Irrigation Impacts on Antioxidant Metabolism Associated with Freezing Tolerance in Creeping Bentgrass

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.140.4.323 ◽

2015 ◽

Vol 140 (4) ◽

pp. 323-332 ◽

Cited By ~ 3

Author(s):

Li-Juan Zhang ◽

Tian-Xiu Zhong ◽

Li-Xin Xu ◽

Lie-bao Han ◽

Xunzhong Zhang

Keyword(s):

Drought Stress ◽

Cold Acclimation ◽

Water Deficit ◽

Freezing Tolerance ◽

Deficit Irrigation ◽

Creeping Bentgrass ◽

Guaiacol Peroxidase ◽

Severe Drought ◽

Antioxidant Metabolism ◽

Mild Drought

Soil water deficit impacts cold acclimation and freezing tolerance in creeping bentgrass (Agrostis stolonifera L.), but the mechanisms underlying have not been well understood. The objectives of this study were to investigate the effects of deficit irrigation before and during cold acclimation on osmoprotectants, antioxidant metabolism, and freezing tolerance in creeping bentgrass. The grass was subjected to three-soil moisture levels: well-watered [100% container capacity (CC)], deficit irrigation induced-mild drought stress (60% CC), and severe drought stress (30% CC) for 35 days including 14 days at 24/20 °C (day/night) and then 21 days under cold acclimation treatment (2 °C) in growth chambers. Leaf proline and total soluble sugar (TSS) levels were higher in the grass under mild drought stress relative to that under severe drought stress. Superoxide (O2−·), hydrogen peroxide (H2O2), and malondialdehyde (MDA) content were higher in the grass under severe drought relative to that under well-watered and mild drought stress at day 35. Mild drought stress increased catalase (CAT) and guaiacol peroxidase (POD) activity, induced new isoforms and increased band intensities of superoxide dismutase (SOD), CAT, and POD during cold acclimation (days 14 to 35). No differences in osmoprotectants, antioxidant metabolism, and freezing tolerance were found between mild drought and well-watered treatments. The results of this study suggest deficit irrigation-induced mild drought stress in late fall and winter could induce accumulation of osmoprotectants and improve antioxidant metabolism, and freezing tolerance, but severe drought stress could reduce freezing tolerance of creeping bentgrass in the region with limited precipitation.

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Conditioned soils reveal plant-selected microbial communities that impact plant drought response

Scientific Reports ◽

10.1038/s41598-021-00593-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Samantha J. Monohon ◽

Daniel K. Manter ◽

Jorge M. Vivanco

Keyword(s):

Drought Stress ◽

Microbial Communities ◽

Plant Biomass ◽

Microbial Community Composition ◽

Defense Responses ◽

Severe Drought ◽

Plant Tolerance ◽

Abiotic Stress Response ◽

Two Generations ◽

Drought Resistant

AbstractRhizobacterial communities can contribute to plant trait expression and performance, including plant tolerance against abiotic stresses such as drought. The conditioning of microbial communities related to disease resistance over generations has been shown to develop suppressive soils which aid in plant defense responses. Here, we applied this concept for the development of drought resistant soils. We hypothesized that soils conditioned under severe drought stress and tomato cultivation over two generations, will allow for plant selection of rhizobacterial communities that provide plants with improved drought resistant traits. Surprisingly, the plants treated with a drought-conditioned microbial inoculant showed significantly decreased plant biomass in two generations of growth. Microbial community composition was significantly different between the inoculated and control soils within each generation (i.e., microbial history effect) and for the inoculated soils between generations (i.e., conditioning effect). These findings indicate a substantial effect of conditioning soils on the abiotic stress response and microbial recruitment of tomato plants undergoing drought stress.

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Effects of mild and severe drought stress on the biomass, phenolic compounds production and photochemical activity of Aloe vera (L.) Burm.f.

Acta agriculturae Slovenica ◽

10.14720/aas.2018.111.2.19 ◽

2018 ◽

Vol 111 (2) ◽

pp. 463 ◽

Cited By ~ 2

Author(s):

Ghader HABIBI

Keyword(s):

Drought Stress ◽

Secondary Metabolite ◽

Soluble Sugars ◽

Compatible Solutes ◽

Aloe Vera ◽

Photochemical Activity ◽

Leaf Biomass ◽

Total Phenolic ◽

Severe Drought ◽

Mild Drought

In this study, the biomass, compatible solutes, PSII functioning and phenolic profiles of Aloe vera (<a title="Carl Linnaeus" href="https://en.wikipedia.org/wiki/Carl_Linnaeus">L.</a>) <a title="" href="https://en.wikipedia.org/wiki/Nicolaas_Laurens_Burman">Burm.f.</a> leaves were investigated at different time intervals after drought stress (20, 40 and 80 % of the field capacity). While the impaired ability of leaves for synthesis of assimilates caused growth inhibition in A. vera under severe drought stress, we observed that the content of proline, soluble sugars, total phenolic and flavonoids tended to increase in plants treated with mild drought stress. Under mild drought stress, the increased leaf thickness correlated with the higher productivity in terms of leaf biomass and gel production. Also, mild drought stress enhanced photochemical activity in Aloe leaves, and changed the entire quantity of secondary metabolite of vanillic acid produced, which may be considered to obtain better growth and considerable secondary metabolite of the medicinal Aloe plants treated with mild drought stress.

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Analysis of tolerance indices for germplasm evaluation in safflower (Carthamus tinctorius L.) subjected to terminal drought stress

South Asian Journal of Experimental Biology ◽

10.38150/sajeb.5(5).p156-161 ◽

2016 ◽

Vol 5 (5) ◽

pp. 156-161

Author(s):

Mehdi Savadkohi Mahforojaki ◽

Reza Talebi ◽

Sayyed Saeid Pourdad

Keyword(s):

Drought Stress ◽

Grain Yield ◽

Block Design ◽

Moisture Stress ◽

Carthamus Tinctorius ◽

Yield Reduction ◽

Potential Yield ◽

Terminal Drought ◽

Terminal Drought Stress ◽

Tolerance Indices

In order to evaluate quantitative drought resistance criteria in some safflower genotypes, fiftheen genotypes were evaluated both under moisture stress and non-stress field environments using a randomized complete block design for each environment. The genotypes showed significant differences in grain yield and other traits. Grain yield under irrigated conditions was adversely correlated with water deficit condition, suggesting that high potential yield under optimal conditions does not necessarily result in improved yield under stress conditions. Genotypes G64, G92 and PI253527 showed lower yield reduction than the average of other genotypes. Surprisingly, most of the genotypes showed more than 30% yield reduction under drought stress. The positive correlation between TOL and irrigated yield (Yp) and the negative correlation between TOL and yield under stress (Ys) suggest that selection based on TOL will result in reduced yield under well-watered conditions. We conclude that GMP and STI are able to discriminate tolerant group of genotypes under both environments. Therefore, genotypes G47, G64, G42 and S411 are superior genotypes for both environments. Genotypes S310 , S149 and Almaneriz are more suitable for non-moisture stress than moisture-stress environment.

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