【摘要】 利用光合气体交换和叶绿素a荧光技术测定了原位沉水和干出条件下红毛菜光合作用的日变化,结果显示与沉水藻体相比,中午干出藻体光合速率、光系统II最大光化学效率(Fv/Fm)、实际光化学效率(ΦPSⅡ)、光化学淬灭系数(qP),光响应曲线初始斜率(ɑETR)和相对电子传递速率(rETR)值下降更明显。干出藻体重新入水后,其叶绿素a荧光参数在两个小时内可以完全恢复到沉水藻体的水平。红毛菜叶绿素a、类胡萝卜素、藻红蛋白的含量在一天中并没有出现明显变化。以上结果表明红毛菜日生长在中午要经历光抑制过程,干出状态下光抑制更严重;干出和沉水藻体光合速率都可以在傍晚得以恢复;红毛菜光系统II反应中心可以通过增加热耗散和降低光合电子传递速率等策略来应对光抑制。更多还原

【Abstract】 The daily course of photosynthesis of Bangia fusco-purpurea in situ was determined by using photosynthetic gas exchange and chlorophyll a fluorescence. The results showed that its photosynthetic rate and chlorophyll a florescence parameters in the emersed algae decreased quicker than that in the submersed algae in noon. When the emersed algae was resubmersed,all chlorophyll a fluorescence parameters could recover to the levels of the submersed algae in two hours,respectively. Insignificant fluctuation of chlorophyll a,carotenoid or phycoerythrin contents was observed in daytime. All above results suggested that the photoinhibition of Bangia fusco-purpurea in situ existed at noon,and the emersed algae exhibited photoinhibition more severe than the submersed algae. The photosynthesis in both submersed and emersed algae could be recovered in evening. The reaction centers of PSⅡin Bangia fusco-purpurea could developed some strategies which contained the increase of thermal dissipation and the reduction of electron transport rate to resist photoinhibition.更多还原