Photosystem I shows a higher tolerance to sorbitol-induced osmotic stress than photosystem II in the intertidal macro-algae Ulva prolifera (Chlorophyta)
Photosystem I shows a higher tolerance to sorbitol-induced osmotic stress than photosystem II in the intertidal macro-algae Ulva prolifera (Chlorophyta)
复制标题
在潮间带大型藻类石莼（绿藻）中，光系统 I 对山梨醇诱导的渗透胁迫具有比光系统 II 更高的耐受性
DOI：
10.1111/ppl.12188
复制
发表时间：
2014-10-01
影响因子：
6.4
通讯作者：
Wang, Guangce
中科院分区：
文献类型：
--
作者：
Gao, Shan;Zheng, Zhenbing;Wang, Guangce
耐脱水的潮间带大型藻类石莼（Ulva prolifera）的光合性能受到山梨醇诱导的渗透胁迫的显著影响。我们的研究结果表明，光合活性随着山梨醇浓度的增加而显著降低。尽管光系统I（PS I）和光系统II（PS II）的部分活性在复水30分钟后能够恢复，但PS II活性比PS I下降得更快。在4M山梨醇浓度下，PS II的活性几乎为0，而PS I的活性仍约为正常水平的三分之一。在1M和2M山梨醇长时间处理后，PS I和PS II的活性缓慢下降，这表明中等浓度的山梨醇对PS I和PS II的影响是渐进的。有趣的是，在这些条件下，对中等渗透胁迫会出现非光化学猝灭增加的情况，而在严重渗透胁迫下则显著下降。这些结果表明，石莼的光保护也可由中等渗透胁迫诱导。此外，PS I的氧化受到渗透胁迫的显著影响。用高浓度山梨醇处理的叶状体中的P700（+）在光系统II被3 -（3,4 - 二氯苯基）- 1,1 - 二甲基脲（DCMU）抑制的情况下仍可被还原，但不能被完全氧化。这一现象可能是由于在含DCMU的海水中复水时，由于受体侧限制（Y(NA)）导致PS I中非光化学能量耗散的量子产率较高所致。
The photosynthetic performance of the desiccation-tolerant, intertidal macro-algae Ulva prolifera was significantly affected by sorbitol-induced osmotic stress. Our results showed that photosynthetic activity decreased significantly with increases in sorbitol concentration. Although the partial activity of both photosystem I (PS I) and photosystem II (PS II) was able to recover after 30min of rehydration, the activity of PS II decreased more rapidly than PS I. At 4M sorbitol concentration, the activity of PS II was almost 0 while that of PS I was still at about one third of normal levels. Following prolonged treatment with 1 and 2M sorbitol, the activity of PS I and PS II decreased slowly, suggesting that the effects of moderate concentrations of sorbitol on PS I and PS II were gradual. Interestingly, an increase in non-photochemical quenching occurred under these conditions in response to moderate osmotic stress, whereas it declined significantly under severe osmotic stress. These results suggest that photoprotection in U. prolifera could also be induced by moderate osmotic stress. In addition, the oxidation of PS I was significantly affected by osmotic stress. P700(+) in the thalli treated with high concentrations of sorbitol could still be reduced, as PS II was inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), but it could not be fully oxidized. This observation may be caused by the higher quantum yield of non-photochemical energy dissipation in PS I due to acceptor-side limitation (Y(NA)) during rehydration in seawater containing DCMU.