scholarly journals Is Photoprotection of PSII One of the Key Mechanisms for Drought Tolerance in Maize?

2021 ◽  
Vol 22 (24) ◽  
pp. 13490
Author(s):  
Nahidah Bashir ◽  
Habib-ur-Rehman Athar ◽  
Hazem M. Kalaji ◽  
Jacek Wróbel ◽  
Seema Mahmood ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Water Status ◽  
Electron Flow ◽  
Photosynthetic Apparatus ◽  
Kernel Weight ◽  
Stress Factors ◽  
Photochemical Quenching ◽  
Yield Attributes ◽  
Maize Hybrids

Drought is one of the most important abiotic stress factors limiting maize production worldwide. The objective of this study was to investigate whether photoprotection of PSII was associated with the degree of drought tolerance and yield in three maize hybrids (30Y87, 31R88, P3939). To do this, three maize hybrids were subjected to three cycles of drought, and we measured the activities of photosystem II (PSII) and photosystem I (PSI). In a second field experiment, three maize hybrids were subjected to drought by withholding irrigation, and plant water status, yield and yield attributes were measured. Drought stress decreased leaf water potential (ΨL) in three maize hybrids, and this reduction was more pronounced in hybrid P3939 (−40%) compared to that of 30Y87 (−30%). Yield and yield attributes of three maize hybrids were adversely affected by drought. The number of kernels and 100-kernel weight was the highest in maize hybrid 30Y87 (−56%, −6%), whereas these were lowest in hybrid P3939 (−88%, −23%). Drought stress reduced the quantum yield of PSII [Y(II)], photochemical quenching (qP), electron transport rate through PSII [ETR(II)] and NPQ, except in P3939. Among the components of NPQ, drought increased the Y(NPQ) with concomitant decrease in Y(NO) only in P3939, whereas Y(NO) increased in drought-stressed plants of hybrid 30Y87 and 31R88. However, an increase in cyclic electron flow (CEF) around PSI and Y(NPQ) in P3939 might have protected the photosynthetic machinery but it did not translate in yield. However, drought-stressed plants of 30Y87 might have sufficiently downregulated PSII to match the energy consumption in downstream biochemical processes. Thus, changes in PSII and PSI activity and development of NPQ through CEF are physiological mechanisms to protect the photosynthetic apparatus, but an appropriate balance between these physiological processes is required, without which plant productivity may decline.

scholarly journals Evaluation of saline-alkali and drought tolerance in maize varieties

2019 ◽  
Vol 48 (4) ◽  
pp. 1047-1063
Author(s):  
Huili Zhang ◽  
Chuang Yuan ◽  
Guillian Mao ◽  
Xue Gao ◽  
Liu Zhu ◽  
...  
Keyword(s):  
Cluster Analysis ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Growth And Development ◽  
Stress Condition ◽  
Stress Factors ◽  
Alkali Stress ◽  
Yield Attributes ◽  
Drought Tolerant ◽  
Maize Varieties

Saline-alkali and drought stresses are one of the abiotic stress factors that limit the normal growth and development of plants. In this work, various agronomic indexes including growth physiology and yield attributes were studied under saline-alkali and drought stress treatments. It was found that the limit of plant growth and development caused by drought stress is much higher than that of saline-alkali stress (p < 0.01). Based on the comprehensive evaluation value (D value), under saline-alkali stress condition, 36 maize varieties could be divided into four groups by cluster analysis (CA): High saline-alkali tolerance (3 varieties), medium saline-alkali tolerant(10 varieties), saline-alkali sensitive (19 varieties), high saline-alkali sensitive (4 varieties). In drought stress condition, 36 maize varieties could be divided into five groups by cluster analysis (CA): High drought-tolerance (2 varieties), medium drought-tolerant (14 varieties), low drought-tolerant (15 varieties), drought-sensitive (4 varieties), high drought-sensitive (1 variety). Therefore, this study provides a comprehensive screening of maize varieties under saline-alkali and drought stresses.

scholarly journals Grain yield and drought tolerance indices of maize hybrids

2020 ◽  
Vol 12 (2) ◽  
pp. 376-386
Author(s):  
Dorina BONEA
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Grain Yield ◽  
Negative Correlation ◽  
Stress Conditions ◽  
Stress Factors ◽  
Tolerance Index ◽  
Maize Hybrids ◽  
Significant Difference ◽  
Tolerance Indices

Drought is one of the major abiotic stress factors limiting crops production in Oltenia area, Romania. In order to study the response of six maize hybrids to drought stress, the trials were conducted in research field of ARDS Simnic – Craiova, during 2017-2018 (non-stressed conditions) and 2018-2019 (drought stress). Six tolerance indices including: abiotic tolerance index (ATI), stress susceptibility percentage index (SSPI), Stress tolerance index (STI), mean productivity (MP), relative drought index (RDI) and golden mean (GM), were utilized on the basis of grain yield. Results from analysis of variance showed that there is a significant difference in 1% of probability level among hybrids in terms of grain yield and tolerance indices. The yield in non-stress conditions (Yp) showed significant positive correlations with ATI, SSPI, STI and MP, and negative correlation with RDI and GM. The yield  in drought conditions (Ys) showed significant positive correlation with RDI and GM, and negative correlation with ATI and SSPI. None of the tolerance indices used could identify the high yielding hybrids under drought and non-stress conditions. Based on the ranking method, the hybrids ‘Felix’ and ‘P 9903’ were the most droughts tolerant. Therefore, they hybrids are recommended to be grown under drought prone areas and to be used as parents for breeding of drought tolerance in other cultivars.

scholarly journals DEHYDRIN PROFILES OF SOME IRANIAN MELON VARIETIES (Cucumis melo L. Merr) UNDER DROUGHT STRE SS CONDITIONS

2019 ◽  
Vol 18 (6) ◽  
pp. 75-84
Author(s):  
Alireza Motallebi-Azar ◽  
István Papp ◽  
Anita Szegő
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Water Content ◽  
Water Status ◽  
Field Capacity ◽  
Total Protein Content ◽  
Severe Drought ◽  
Molecular Weights ◽  
Potential Marker ◽  
Relative Water

Dehydrins are proteins that play a role in the mechanism of drought tolerance. This study aimed at establishing dehydrin profile and accumulation in four local melon varieties of Iran: Mino, Dargazi, Saveii, and Semsori, as well as in a commercial variety Honeydew. Plants were treated with drought stress by adjusting the soil water content to 75, 50, 40, 30 and 20% of field capacity (FC) by withholding water. Water status of plants was monitored based on the seedling fresh weight (FW) and relative water content of leaves (RWC). Total protein content was extracted, then heat-stable protein (HSP) fraction was isolated for each variety and water stress treatment. After SDS-PAGE of HSP, Western blotting analysis was carried out with Anti-dehydrin rabbit (primary) and Goat anti rabbit (secondary) antibodies. ANOVA results showed that with decreasing FC below 75%, FW and RWC decreased, but these changes significantly varied among genotypes. On the basis of FW and RWC data under different drought stress treatments, the following drought-tolerant ranking was established: Mino > Dargazi > Saveii and Honeydew > Semsori, from tolerant to sensitive order. Results of Western blot analysis showed that expression of some proteins with molecular weights of 19–52 kDa was induced in the studied varieties under drought stress (% FC). Expression level of the dehydrin proteins in different varieties was variable and also depending on the drought stress level applied. However, dehydrin proteins (45 and 50 kDa) showed strong expression levels in all varieties under severe drought stress (20% FC). The abundance of dehydrin proteins was higher in tolerant varieties (Mino and Dargazi) than in moderate and drought sensitive genotypes. Consequently, dehydrins represent a potential marker for selection of genotypes with enhanced drought tolerance.

scholarly journals Physiological Responses under Drought Stress of Improved Drought-Tolerant Rice Lines and their Parents

2018 ◽  
Vol 46 (2) ◽  
pp. 679-687 ◽  
Author(s):  
Preeyanuch LARKUNTHOD ◽  
Noppawan NOUNJAN ◽  
Jonaliza L SIANGLIW ◽  
Theerayut TOOJINDA ◽  
Jirawat SANITCHON ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Water Status ◽  
Physiological Responses ◽  
High Water ◽  
Recurrent Parent ◽  
Potential Candidate ◽  
Substitution Lines ◽  
Chromosome Segment Substitution Lines ◽  
Drought Tolerant

Many of the economically important rice cultivars including ‘Khao Dawk Mali 105’ (KDML105) or jasmine rice, one of the world’s famous rice exported from Thailand suffers from drought due to erratic rainfalls and limited irrigation. To improve drought tolerance and reserve genetic background of KDML105, chromosome segment substitution lines (CSSL) containing drought tolerant quantitative trait loci (DT-QTL) has been previously developed by backcrossing between KDML105 and drought tolerant donor, IR58586-F2-CA-143 (DH212). To understand the physiological responses related to drought tolerance in CSSL lines compared to parents, two CSSLs namely CSSL1-16 and CSSL1-18, respectively were used in this study. Twenty-one-d-old hydroponically grown plants were subjected to 20% PEG for 0, 7, 14 d and then recovered from stress for 3 d. The results indicated that CSSL lines especially, CSSL1-16 showed better performance under drought stress compared to their recurrent parent. Drought tolerance superior CSSL1-16 line was indicated by high water status (high relative water content and leaf water potential), good osmotic adjustment, high proline and greater membrane stability. Moreover, this line was able to resume growth after stress recovery whereas other lines/cultivar could not recover. Similarly, drought tolerant donor showed high water status suggesting that well-maintained plant water status was associated with drought tolerant trait. It could be concluded that the highest drought tolerant line was CSSL1-16 followed by DH212, CSSL1-18 and KDML105. It would be interesting to go further into introgressed section in CSSL1-16 to identify potential candidate genes in DT-QTL for breeding drought tolerant rice in the future.

Acquired tolerance of the photosynthetic apparatus to photoinhibition as a result of growing Solanum lycopersicum at moderately higher temperature and light intensity

2019 ◽  
Vol 46 (6) ◽  
pp. 555 ◽  
Author(s):  
Milena T. Gerganova ◽  
Aygyun K. Faik ◽  
Maya Y. Velitchkova
Keyword(s):  
High Temperature ◽  
Quantum Yield ◽  
Light Intensity ◽  
Electron Flow ◽  
Photosynthetic Apparatus ◽  
High Light ◽  
Cyclic Electron Flow ◽  
Photochemical Quenching ◽  
Kinetics Of ◽  
Moderately High Temperature

The kinetics of photoinhibition in detached leaves from tomato plants (Solanium lycopersicum L. cv. M82) grown for 6 days under different combinations of optimal and moderately high temperature and optimal and high light intensity were studied. The inhibition of PSII was evaluated by changes in maximal quantum yield, the coefficient of photochemical quenching and the quantum yield of PSII. The changes of PSI activity was estimated by the redox state of P700. The involvement of different possible protective processes was checked by determination of nonphotochemical quenching and cyclic electron flow around PSI. To evaluate to what extent the photosynthetic apparatus and its response to high light treatment was affected by growth conditions, the kinetics of photoinhibition in isolated thylakoid membranes were also studied. The photochemical activities of both photosystems and changes in the energy distribution and interactions between them were evaluated by means of a Clark electrode and 77 K fluorescence analysis. The data showed an increased tolerance to photoinhibition in plants grown under a combination of moderately high temperature and light intensity, which was related to the stimulation of cyclic electron flow, PSI activity and rearrangements of pigment–protein complexes, leading to a decrease in the excitation energy delivered to PSII.

scholarly journals Photosynthesis Regulation in Response to Fluctuating Light in the Secondary Endosymbiont Alga Nannochloropsis gaditana

2019 ◽  
Vol 61 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Alessandra Bellan ◽  
Francesca Bucci ◽  
Giorgio Perin ◽  
Alessandro Alboresi ◽  
Tomas Morosinotto
Keyword(s):  
Electron Transport ◽  
Electron Flow ◽  
Incident Light ◽  
Photosynthetic Apparatus ◽  
Photosynthetic Electron Transport ◽  
Thermal Dissipation ◽  
Photochemical Quenching ◽  
Nannochloropsis Gaditana ◽  
Fluctuating Light ◽  
Light Fluctuations

Abstract In nature, photosynthetic organisms are exposed to highly dynamic environmental conditions where the excitation energy and electron flow in the photosynthetic apparatus need to be continuously modulated. Fluctuations in incident light are particularly challenging because they drive oversaturation of photosynthesis with consequent oxidative stress and photoinhibition. Plants and algae have evolved several mechanisms to modulate their photosynthetic machinery to cope with light dynamics, such as thermal dissipation of excited chlorophyll states (non-photochemical quenching, NPQ) and regulation of electron transport. The regulatory mechanisms involved in the response to light dynamics have adapted during evolution, and exploring biodiversity is a valuable strategy for expanding our understanding of their biological roles. In this work, we investigated the response to fluctuating light in Nannochloropsis gaditana, a eukaryotic microalga of the phylum Heterokonta originating from a secondary endosymbiotic event. Nannochloropsis gaditana is negatively affected by light fluctuations, leading to large reductions in growth and photosynthetic electron transport. Exposure to light fluctuations specifically damages photosystem I, likely because of the ineffective regulation of electron transport in this species. The role of NPQ, also assessed using a mutant strain specifically depleted of this response, was instead found to be minor, especially in responding to the fastest light fluctuations.

scholarly journals Effects of salicylic acid, zinc and glycine betaine on morpho-physiological growth and yield of maize under drought stress

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ramadan Shemi ◽  
Rui Wang ◽  
El-Sayed M. S. Gheith ◽  
Hafiz Athar Hussain ◽  
Saddam Hussain ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Antioxidant Enzymes ◽  
Drought Stress ◽  
Gas Exchange ◽  
Drought Tolerance ◽  
Glycine Betaine ◽  
Field Capacity ◽  
Yield Attributes ◽  
Chlorophyll Contents ◽  
Water Conditions

AbstractDrought is one of the major environmental stresses that negatively affect the maize (Zea mays L.) growth and production throughout the world. Foliar applications of plant growth regulators, micronutrients or osmoprotectants for stimulating drought-tolerance in plants have been intensively reported. A controlled pot experiment was conducted to study the relative efficacy of salicylic acid (SA), zinc (Zn), and glycine betaine (GB) foliar applications on morphology, chlorophyll contents, relative water content (RWC), gas-exchange attributes, activities of antioxidant enzymes, accumulations of reactive oxygen species (ROS) and osmolytes, and yield attributes of maize plants exposed to two soil water conditions (85% field capacity: well-watered, 50% field capacity: drought stress) during critical growth stages. Drought stress significantly reduced the morphological parameters, yield and its components, RWC, chlorophyll contents, and gas-exchange parameters except for intercellular CO2 concentration, compared with well water conditions. However, the foliar applications considerably enhanced all the above parameters under drought. Drought stress significantly (p < 0.05) increased the hydrogen peroxide and superoxide anion contents, and enhanced the lipid peroxidation rate measured in terms of malonaldehyde (MDA) content. However, ROS and MDA contents were substantially decreased by foliar applications under drought stress. Antioxidant enzymes activity, proline content, and the soluble sugar were increased by foliar treatments under both well-watered and drought-stressed conditions. Overall, the application of GB was the most effective among all compounds to enhance the drought tolerance in maize through reduced levels of ROS, increased activities of antioxidant enzymes and higher accumulation of osmolytes contents.

Evaluation of wild barley species as possible sources of drought tolerance for arid environments

2017 ◽  
Vol 16 (3) ◽  
pp. 209-217 ◽  
Author(s):  
Mohammad Barati ◽  
Mohammad Mahdi Majidi ◽  
Fateme Mostafavi ◽  
Aghafakhr Mirlohi ◽  
Maryam Safari ◽  
...  
Keyword(s):  
Drought Stress ◽  
Drought Tolerance ◽  
Wild Species ◽  
Wild Barley ◽  
Principal Component ◽  
Kernel Weight ◽  
Stress Conditions ◽  
Wild Plants ◽  
Arid Environments ◽  
Barley Genotypes

AbstractIn this study, agro-morphological and yield-related traits associated with drought tolerance in 80 barley genotypes belonging to 15 wild species together with the cultivated one, and their potential to improve adaptation to different levels of drought stress conditions (moisture environments) were studied. There was significant genetic variation among the genotypes and species for all of the measured traits, as well as differential responses of genotypes across environments. The results indicated high variation for grain yield (GY) under drought stress among the genotypes, and that some of the wild genotypes had consistently superior specific adaptation to the water stress conditions. The genotypes belong to wild barley species, especially Hordeum murinum and Hordeum marinum had lower GY but relatively higher yield stability under different environments. Traits such as number of seed per plant and hundred kernel weight were positively correlated with GY in all of the environments. High negative correlation between GY and days to ripening was observed only under intense drought environment, showing drought escape as a strategy of wild plants under highly stressed conditions. Grouping of the genotypes by principal component analysis completely separated cultivated barley and its progenitor (Hordeum vulgare ssp. spontaneum) from other wild genotypes; however, the other wild species were slightly separated from each other. In addition, the Iranian and foreign genotypes did not completely separate from each other. The identified wild barley genotypes with favourable characters and high drought tolerance could be used in genetic studies and barley improvement programmes especially for drought stress.

scholarly journals Screening of Onion (Allium cepa L.) Genotypes for Drought Tolerance Using Physiological and Yield Based Indices Through Multivariate Analysis

2021 ◽  
Vol 12 ◽  
Author(s):  
Pranjali A. Gedam ◽  
A. Thangasamy ◽  
Dhananjay V. Shirsat ◽  
Sourav Ghosh ◽  
K. P. Bhagat ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Enzyme Activity ◽  
Drought Stress ◽  
Drought Tolerance ◽  
Antioxidant Enzyme ◽  
Leaf Area ◽  
Antioxidant Enzyme Activity ◽  
Yield Attributes ◽  
Highly Sensitive ◽  
Bulb Yield

Drought is a leading abiotic constraints for onion production globally. Breeding by using unique genetic resources for drought tolerance is a vital mitigation strategy. With a total of 100 onion genotypes were screened for drought tolerance using multivariate analysis. The experiment was conducted in a controlled rainout shelter for 2 years 2017–2018 and 2018–2019 in a randomized block design with three replications and two treatments (control and drought stress). The plant was exposed to drought stress during the bulb development stage (i.e., 50–75 days after transplanting). The genotypes were screened on the basis of the drought tolerance efficiency (DTE), percent bulb yield reduction, and results of multivariate analysis viz. hierarchical cluster analysis by Ward’s method, discriminate analysis and principal component analysis. The analysis of variance indicated significant differences among the tested genotypes and treatments for all the parameters studied, viz. phenotypic, physiological, biochemical, and yield attributes. Bulb yield was strongly positively correlated with membrane stability index (MSI), relative water content (RWC), total chlorophyll content, antioxidant enzyme activity, and leaf area under drought stress. The genotypes were categorized into five groups namely, highly tolerant, tolerant, intermediate, sensitive, and highly sensitive based on genetic distance. Under drought conditions, clusters II and IV contained highly tolerant and highly sensitive genotypes, respectively. Tolerant genotypes, viz. Acc. 1656, Acc. 1658, W-009, and W-085, had higher DTE (&gt;90%), fewer yield losses (&lt;20%), and performed superiorly for different traits under drought stress. Acc. 1627 and Acc. 1639 were found to be highly drought-sensitive genotypes, with more than 70% yield loss. In biplot, the tolerant genotypes (Acc. 1656, Acc. 1658, W-085, W-009, W-397, W-396, W-414, and W-448) were positively associated with bulb yield, DTE, RWC, MSI, leaf area, and antioxidant enzyme activity under drought stress. The study thus identified tolerant genotypes with favorable adaptive traits that may be useful in onion breeding program for drought tolerance.

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