Drought Stress
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2021 ◽  
Vol 311 ◽  
pp. 108693
Hongxia Zhang ◽  
Xinrong Li ◽  
Dexin Guan ◽  
Anzhi Wang ◽  
Fenghui Yuan ◽  

Phyton ◽  
2022 ◽  
Vol 91 (3) ◽  
pp. 633-649
M. Rafiqul Islam ◽  
M. Shahinur Islam ◽  
Nurunnaher Akter ◽  
Mohammed Mohi-Ud-Din ◽  
Mohammad Golam Mostofa

2021 ◽  
Vol 11 (1) ◽  
Samantha J. Monohon ◽  
Daniel K. Manter ◽  
Jorge M. Vivanco

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.

2021 ◽  
Vol 21 (1) ◽  
Mehdi Rahimi ◽  
Mojtaba Kordrostami ◽  
Fereshteh Mohamadhasani ◽  
Sanam Safaei Chaeikar

Abstract Background Abiotic and biotic stresses induce oxidative processes in plant cells that this process starts with the production of ROSs which cause damage to the proteins. Therefore, plants have increased their antioxidant activity to defend against this oxidative stress to be able to handle stress better. In this research, 14 different tea accessions in a randomized complete block design with two replications were evaluated in two normal and drought stress conditions, and their antioxidant activity was measured by DPPH-free radicals’ assay and gene expression analysis. Results The results of gene expression analysis showed that the 100 and 399 accessions and Bazri cultivar had high values for most of the antioxidant enzymes, ascorbate peroxidase, superoxide dismutase, catalase, and peroxidase under drought stress conditions while the 278 and 276 accessions had the lowest amount of antioxidant enzymes in the same situation. Results showed that the IC50 of the BHT combination was 90.12 μg/ ml. Also, The IC50 of accessions ranged from 218 to 261 μg/ml and 201–264 μg/ml at normal and drought stress conditions, respectively. The 100 and 399 accessions showed the lowest IC50 under normal and drought stress conditions, while 278 and 276 accessions had the highest value for IC50. The antioxidant activity of tea accession extracts under normal conditions was ranged from 25 to 69% for accessions 278 and 100, respectively. While, the antioxidant activities of extracts under drought stress condition was 12 to 83% for accessions 276 and 100, respectively. So, according to the results, 100 and 399 accessions exhibited the least IC50 and more antioxidant activity under drought stress conditions and were identified as stress-tolerant accessions. However, 278 and 276 accessions did not show much antioxidant activity and were recognized as sensitive accessions under drought stress conditions. Conclusions These results demonstrate that total phenol content, antioxidant activity, and the oxygen-scavenging system can be used as a descriptor for identifying drought-tolerant accessions.

Nadiyah M. Alabdallah ◽  
Md. Mahadi Hasan ◽  
Abdalrhaman M. Salih ◽  
S.S. Roushdy ◽  
Aisha S. Al-Shammari ◽  

Drought stress is a significant abiotic stressor that has a negative impact on crop production and global food security systems. Drought stress was applied to eggplant seedlings with various field capacities (FC), 80% FC as control, 50% FC, 35% FC, and 20% FC. AgNPs were synthesised from green chemical methods, whereas different concentrations of AgNPs (0, 0.1, 0.2, 0.5 µmol) were applied exogenously on drought-stressed eggplants. Drought stress decreased the growth parameters (plant height, fresh mass, dry mass, leaf area), photosynthetic pigments (Chl a, Chl b, carotenoids), and protein content while increased the proline, hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>), malondialdehyde (MDA) content, and activity of the antioxidant enzymes, i.e., superoxide dismutase (SOD) and catalase (CAT). AgNPs restricted proline accumulation and reduced H<sub>2</sub>O<sub>2,</sub> MDA content by upregulating the antioxidant enzymes. Overall, the current study’s findings indicated that AgNPs are an effective eco-friendly and low-cost application for plant growth under drought stress, with the potential to mitigate the impact of drought on plants.

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2282
Kyung-Hee Kim ◽  
Jae Yoon Kim

Wheat starch is one of the most important components in wheat grain and is extensively used as the main source in bread, noodles, and cookies. The wheat endosperm is composed of about 70% starch, so differences in the quality and quantity of starch affect the flour processing characteristics. Investigations on starch composition, structure, morphology, molecular markers, and transformations are providing new and efficient techniques that can improve the quality of bread wheat. Additionally, wheat starch composition and quality are varied due to genetics and environmental factors. Starch is more sensitive to heat and drought stress compared to storage proteins. These stresses also have a great influence on the grain filling period and anthesis, and, consequently, a negative effect on starch synthesis. Sucrose metabolizing and starch synthesis enzymes are suppressed under heat and drought stress during the grain filling period. Therefore, it is important to illustrate starch and sucrose mechanisms during plant responses in the grain filling period. In recent years, most of these quality traits have been investigated through genetic modification studies. This is an attractive approach to improve functional properties in wheat starch. The new information collected from hybrid and transgenic plants is expected to help develop novel starch for understanding wheat starch biosynthesis and commercial use. Wheat transformation research using plant genetic engineering technology is the main purpose of continuously controlling and analyzing the properties of wheat starch. The aim of this paper is to review the structure, biosynthesis mechanism, quality, and response to heat and drought stress of wheat starch. Additionally, molecular markers and transformation studies are reviewed to elucidate starch quality in wheat.

Hu Sun ◽  
Qi Shi ◽  
Ning-Yu Liu ◽  
Shi-Bao Zhang ◽  
Wei Huang

Fluctuating light (FL) and drought stress usually occur concomitantly. However, whether drought stress affects photosynthetic performance under FL remains unknown. Here, we measured gas exchange, chlorophyll fluorescence, and P700 redox state under FL in drought-stressed tomato (Solanum lycopersicum) seedlings. Drought stress significantly affected stomatal opening and mesophyll conductance after transition from low to high light and thus delayed photosynthetic induction under FL. Therefore, drought stress exacerbated the loss of carbon gain under FL. Furthermore, restriction of CO2 fixation under drought stress aggravated the over-reduction of photosystem I (PSI) upon transition from low to high light. The resulting stronger FL-induced PSI photoinhibition significantly supressed linear electron flow and PSI photoprotection. These results indicated that drought stress not only affected gas exchange under FL but also accelerated FL-induced photoinhibition of PSI. Furthermore, drought stress enhanced relative cyclic electron flow in FL, which partially compensated for restricted CO2 fixation and thus favored PSI photoprotection under FL. Therefore, drought stress has large effects on photosynthetic dark and light reactions under FL.

2021 ◽  
Hanifeh Seyed Hajizadeh ◽  
Sahar Azizi ◽  
Farzad Rasouli ◽  
Volkan Okatan

Abstract Drought is a major abiotic stress that prevents plant growth and efficiency. Silicon increases drought tolerance by regulating the biosynthesis and acumulation of some osmolits.This study was conducted to modulate dought stress induced by Polyethylene glycol (PEG) in two genotypes of damasks by nano silicon dioxide (nSiO2). The experiment included three levels of nSiO2 (0, 50 and 100 mg L-1) and PEG (0, 25, 50, 75 and 100 g L-1) added to culture medium. Drought stress decreased protein content while Maragheh genotype under normal conditios and treating with 100 mg L-1 nSiO2 had the highest protein content. Under severe drought stress Maragheh genotype had stronger membrane stability index (MSI) than Kashan genotype and explants treated with 100 mg L-1 nSiO2 had the highest MSI in control plants. Contrary to the negative effects of drought, plants treated with 100 mg L−1 nSiO2 maintained more of their photosynthetic parameters in comparison with other treatments and showed higher amount of protein and proline in Maragheh rather than kashan genotype. Drought stress reduced the values of Fm, Fv/Fm, and Fv. In general, under drought stress, treatment with nSiO2 increased the mentioned characteristics before. It also improved water deficit tolerance through enhancing in the activity of antioxidant enzymes such as catalase, peroxidase, guaiacol peroxidase and superoxide dismutase while the amount of lipid peroxidation and hydrogen peroxide decreased. The results showed that Maragheh genotype may be more stronger in counter with water deficit by improving in water balance, antioxidant enzyme activities, and membrane stability.

Yihong Wang ◽  
Zhengyan Yang ◽  
Xin Chen ◽  
Dan Han ◽  
Jing Han ◽  

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