Chen Zhen, Lu GaoFei, Chen Shuo, Chen XiongWen
College of Life Sciences and Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, Hubei Normal University, Huangshi, Hubei, China 435002.
J Phycol. 2011 Oct;47(5):1063-71. doi: 10.1111/j.1529-8817.2011.01033.x. Epub 2011 Aug 19.
The PSII photochemical activity in a terrestrial cyanobacterium Nostoc commune Vaucher ex Bornet et Flahault during rewetting was undetectable in the dark but was immediately recognized in the light. The maximum quantum yield of PSII (Fv /Fm ) during rewetting in the light rose to 85% of the maximum within ∼30 min and slowly reached the maximum within 6 h, while with rewetting in the darkness for 6 h and then exposure to light the recovery of Fv /Fm required only ∼3 min. These results suggested that recovery of photochemical activity might depend on two processes, light dependence and light independence, and the activation of photosynthetic recovery in the initial phase was severely light dependent. The inhibitor experiments showed that the recovery of Fv /Fm was not affected by chloramphenicol (CMP), but severely inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) in the light, suggesting that the light-dependent recovery of photochemical activity did not require de novo protein synthesis but required activation of PSII associated with electron flow to plastoquinone. Furthermore, the test indicated that the lower light intensity and the red light were of benefit to its activation of photochemical activity. In an outdoor experiment of diurnal changes of photochemical activity, our results showed that PSII photochemical activity was sensitive to light fluctuation, and the nonphotochemical quenching (NPQ) was rapidly enhanced at noon. Furthermore, the test suggested that the repair of PSII by de novo protein synthesis played an important role in the acclimation of photosynthetic apparatus to high light, and the heavily cloudy day was more beneficial for maintaining high photochemical activity.
陆生蓝藻普通念珠藻（Nostoc commune Vaucher ex Bornet et Flahault）在复水过程中，其光系统II（PSII）的光化学活性在黑暗中无法检测到，但在光照下可立即被识别。在光照下复水期间，PSII的最大量子产率（Fv /Fm）在约30分钟内升至最大值的85%，并在6小时内缓慢达到最大值，而在黑暗中复水6小时后再光照，Fv /Fm的恢复仅需约3分钟。这些结果表明，光化学活性的恢复可能依赖于两个过程，即光依赖和光独立过程，并且初始阶段光合恢复的激活严重依赖光。抑制剂实验表明，Fv /Fm的恢复不受氯霉素（CMP）影响，但在光照下受到3-(3,4-二氯苯基)-1,1-二甲基脲（DCMU）的严重抑制，这表明光依赖的光化学活性恢复不需要从头合成蛋白质，但需要与向质体醌的电子流相关的PSII激活。此外，测试表明较低的光强度和红光有利于其光化学活性的激活。在光化学活性日变化的室外实验中，我们的结果表明PSII光化学活性对光波动敏感，中午非光化学猝灭（NPQ）迅速增强。此外，测试表明通过从头合成蛋白质对PSII的修复在光合机构对高光的适应中起重要作用，并且阴天更有利于维持高光化学活性。
