Investigating primary sites of damage in photosystem II in response to high temperature

2015 ◽  
Vol 20 (4) ◽  
pp. 304-309
Author(s):  
Divya Agrawal ◽  
Anjana Jajoo
Keyword(s):  
High Temperature ◽  
Photosystem Ii

Changes in photosynthesis, chlorophyll fluorescence, and antioxidant enzymes of mulberry (Morus ssp.) in response to salinity and high-temperature stress

Biologia ◽  
2013 ◽  
Vol 68 (3) ◽  
Author(s):  
Cui Yu ◽  
Shujun Huang ◽  
Xingming Hu ◽  
Wen Deng ◽  
Chao Xiong ◽  
...  
Keyword(s):  
Antioxidant Enzymes ◽  
High Temperature ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Peroxidase Activity ◽  
High Temperature Stress ◽  
The Other ◽  
Fluorescence Parameters ◽  
Photosystem Ii Photochemistry ◽  
Chl Fluorescence

AbstractPhotosynthesis, chlorophyll (Chl) fluorescence, and antioxidant enzymes were measured in the mulberry (Morus spp.) cultivars Da 10, Hongguo 2, Anza 1, and Taiwan 72C002, which were subjected to salinity and high-temperature stress (STS; 0.1%, 0.3%, and 0.5% NaCl concentrations, 34.5°C–40.5°C/27.8°C–29.2°C day/night temperatures). Control plants were watered with 1 L of full-strength Hoagland’s nutrient solution with no added NaCl. Net photosynthetic rate (P N), stomatal conductance (g s), and effective quantum yield of photosystem II photochemistry (ΦPSII) increased in Anza 1 and Taiwan 72C002 under 0.1% STS but decreased in Da 10 and Hongguo 2 compared with the control. However, all the above parameters, including Chl content, maximum quantum yield of photosystem II photochemistry (Fv/Fm), nonphotochemical quenching (NPQ), and maximum carboxylation velocity of Rubisco (V cmax, decreased in Taiwan 72C002, Honggua 2, and Da 10 under 0.3% and 0.5% STS, suggesting that photoinhibition occurred under severe STS. Under STS, there were no significant changes in P N, Fv/Fm, ΦPSII, ascorbate peroxidase (APX) activity, superoxide dismutase (SOD) activity, catalase activity, superoxide anion radical (O2−) content, malondialdehyde (MDA) content, soluble sugar content (SSC), and leaf biomass in Anza 1 even at 0.5% STS, showing that Anza 1 displays high resistance to STS. In addition, peroxidase activity was significantly higher in Anza 1 than in the other mulberry cultivars. Significant adverse effects of severe salinity on photosynthesis and Chl fluorescence parameters were observed in Da 10. Additionally, SOD, peroxidase, and APX activities were lower in Da 10, whereas O2− and MDA contents were higher in comparison with the other mulberry cultivars under 0.3% and 0.5% STS, suggesting that Da 10 had low resistance to STS. These results show that 0.1% STS had a positive effect on photosynthesis and Chl fluorescence parameters in Anza 1 and Taiwan 72C002, and higher peroxidase activity can to a certain extent explain the higher STS tolerance in Anza 1. Damages to DSM photosystems might be related to lower SOD, POD, and APX activities, which resulted in the accumulation of reactive oxygen species.

Effect of Reducing Nitric Oxide in Rumex K-1 Leaves on the Photoprotection of Photosystem II Under High Temperature with Strong Light

2016 ◽  
Vol 35 (4) ◽  
pp. 1118-1125 ◽  
Author(s):  
Xingkai Che ◽  
Zishan Zhang ◽  
Liqiao Jin ◽  
Meijun Liu ◽  
Yuting Li ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
High Temperature ◽  
Photosystem Ii ◽  
Strong Light
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