scholarly journals Salt Stress Inhibits the Repair of Photodamaged Photosystem II by Suppressing the Transcription and Translation of psbA Genes in Synechocystis

2002 ◽  
Vol 130 (3) ◽  
pp. 1443-1453 ◽  
Author(s):  
S. I. Allakhverdiev
Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 272 ◽  
Author(s):  
Chiu-Yueh Lan ◽  
Kuan-Hung Lin ◽  
Wen-Dar Huang ◽  
Chang-Chang Chen

Wheat is a staple food worldwide, but its productivity is reduced by salt stress. In this study, the mitigative effects of 22 μM selenium (Se) on seedlings of the wheat (Triticum aestivum L.) cultivar Taichung SEL. 2 were investigated under different salt stress levels (0, 100, 200, 300, and 400 mM NaCl). Results of the antioxidative capacity showed that catalase (CAT) activity, non-enzymatic antioxidants (total phenols, total flavonoids, and anthocyanins), 1,1-Diphenyl-2-Picryl-Hydrazyl (DPPH) radical-scavenging activity, and the reducing power of Se-treated seedlings were enhanced under saline conditions. The more-stabilized chlorophyll fluorescence parameters (maximal quantum yield of photosystem II (Fv/Fm), minimal chlorophyll fluorescence (F0), effective quantum yield of photosystem II (ΦPSII), quantum yield of regulated energy dissipation of photosystem II (Y(NPQ)), and quantum yield of non-regulated energy dissipation of photosystem II (Y(NO)) and the less-extensive degradation of photosynthetic pigments (total chlorophyll and carotenoids) in Se-treated seedlings were also observed under salt stress. The elongation of shoots and roots of Se-treated seedling was also preserved under salt stress. Protection of these physiological traits in Se-treated seedlings might have contributed to stable growth observed under salt stress. The present study showed the protective effect of Se on the growth and physiological traits of wheat seedlings under salt stress.


2020 ◽  
Vol 21 (17) ◽  
pp. 6036
Author(s):  
Qiushuo Song ◽  
Madhumita Joshi ◽  
Vijay Joshi

Watermelon (Citrullus lanatus L.) is a widely popular vegetable fruit crop for human consumption. Soil salinity is among the most critical problems for agricultural production, food security, and sustainability. The transcriptomic and the primary molecular mechanisms that underlie the salt-induced responses in watermelon plants remain uncertain. In this study, the photosynthetic efficiency of photosystem II, free amino acids, and transcriptome profiles of watermelon seedlings exposed to short-term salt stress (300 mM NaCl) were analyzed to identify the genes and pathways associated with response to salt stress. We observed that the maximal photochemical efficiency of photosystem II decreased in salt-stressed plants. Most free amino acids in the leaves of salt-stressed plants increased many folds, while the percent distribution of glutamate and glutamine relative to the amino acid pool decreased. Transcriptome analysis revealed 7622 differentially expressed genes (DEGs) under salt stress, of which 4055 were up-regulated. The GO analysis showed that the molecular function term “transcription factor (TF) activity” was enriched. The assembled transcriptome demonstrated up-regulation of 240 and down-regulation of 194 differentially expressed TFs, of which the members of ERF, WRKY, NAC bHLH, and MYB-related families were over-represented. The functional significance of DEGs associated with endocytosis, amino acid metabolism, nitrogen metabolism, photosynthesis, and hormonal pathways in response to salt stress are discussed. The findings from this study provide novel insights into the salt tolerance mechanism in watermelon.


2019 ◽  
Vol 57 (2) ◽  
pp. 564-571 ◽  
Author(s):  
Y.-Y. GUO ◽  
H.-S. NIE ◽  
H.-Y. YU ◽  
D.-S. KONG ◽  
J.-Y. WU

Author(s):  
Jônatas R. M. de Sousa ◽  
Hans R. Gheyi ◽  
Marcos E. B. Brito ◽  
Claudivan F. de Lacerda ◽  
Francisco V. da Silva ◽  
...  

ABSTRACT This study aimed to evaluate the salt tolerance of 'Mimo do Céu' orange grafted onto three rootstocks using physiological parameters such as maximum quantum efficiency of photosystem II (PSII) and the production of fruits. It also evaluated the effectiveness of increased nitrogen (N) fertilization in reducing the effects of salt stress. Two concomitant experiments were carried out under controlled conditions, using drainage lysimeters. The Experiment I evaluated the effects of the application of five levels of saline water on three combinations of scion-rootstocks grafted with 'Mimo de Ceu' orange, in a randomized block design with three replicates in a 5 x 3 factorial scheme. The Experiment II evaluated the application of two N levels (100 and 200% of recommendation) in three scion-rootstock combinations irrigated with water of electrical conductivity of 3.0 dS m-1, in a 3 x 2 factorial scheme, with three replicates. The maximum quantum efficiency of PSII was inhibited in citrus plants under salt stress. 'Mimo do Ceu' orange grafted onto 'Common' Rangpur lime has higher yield potential. The increase in N dose did not reduce the deleterious effects of water salinity on fruit production.


2012 ◽  
Vol 34 (4) ◽  
pp. 1245-1255 ◽  
Author(s):  
Cicero Cartaxo de Lucena ◽  
Dalmo Lopes de Siqueira ◽  
Hermínia Emilia Prieto Martinez ◽  
Paulo Roberto Cecon

This study evaluated the tolerance of mango cultivars 'Haden', 'Palmer', 'Tommy Atkins' and 'Uba' grafted on rootstock 'Imbú' to salt stress using chlorophyll fluorescence. Plants were grown in modified Hoagland solution containing 0, 15, 30, and 45 mmol L-1 NaCl. At 97 days the parameters of the chlorophyll fluorescence (F0, Fm, Fv, F0/Fm, Fv/Fm, Fv'/Fm', ΦPSII = [(Fm'-Fs)/(Fm')], D = (1- Fv'/Fm') and ETR = (ΦPSII×PPF×0,84×0,5) were determined. At 100 days, the leaf emission and leaf area, toxicity and leaf abscission indexes were determined. In all cultivars evaluated, in different degree, there were decreases in photochemical efficiency of photosystem II, enhanced concentrations from 15 mmol L-1 NaCl. The decreases in the potential quantum yield of photosystem II (Fv/Fm) were 27.9, 18.7, 20.5, and 27.4%, for cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba', respectively, when grown in 45 mmol L-1 NaCl. It was found decreases in leaf emission and mean leaf area in all cultivars from 15 mmol L-1 NaCl. There were increases in leaf toxicity of 33.0, 67.5, 41.6 and 80.8% and in leaf abscission of 71.8, 29.2, 32.5, and 67.9% for the cultivars 'Haden', 'Palmer', 'Tommy Atkins', and 'Uba' respectively, when grown in 45 mmol L-1 NaCl. Leaf toxicity and leaf abscission were not observed in 15 mmol L-1 NaCl. The decrease in Fv/Fm ratio were accompanied by decreasing in leaf emission and increased leaf toxicity index, showing, therefore, the potential of chlorophyll fluorescence in the early detection of salt stress in mango tree.


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