光波动频率影响黄瓜幼苗光合作用的机制  

Effects of changing frequency of fluctuating light on photosynthesis in cucumber seedlings

作　　者：乔美玉 张雅君 刘立安[1] 石雷[1] 马庆虎[1] 姜闯道[1] QIAO Mei Yu;ZHANG YaJun;LIU LiAn;SHI Lei;Ma QingHu;JIANG ChuangDao(Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China;University of Chinese Academy of Sciences, Beijing 100049, China)

机构地区：[1]中国科学院植物研究所中国科学院北方资源植物重点实验室,北京100093 [2]中国科学院大学,北京100049

出　　处：《中国科学：生命科学》2019年第3期280-288,共9页Scientia Sinica(Vitae)

基　　金：国家自然科学基金(批准号:31571576)资助

摘　　要：自然条件下环境光强往往是波动的,但波动光变化频率影响植物光合作用的机制尚不清楚.为了探讨植物光合作用对波动光频率的响应及机制,本文以黄瓜为材料,对植物生长、叶绿素含量、气体交换、叶绿素荧光以及抗氧化酶进行了研究.结果显示,相对于弱光(T4),强光下(T1, T2和T3)黄瓜株高、生物量、叶面积和比叶重均明显较高,但波动频率增加(T2, T3)能够导致这些参数值降低.强光与弱光处理相比其叶绿素总量较低,且随着波动光频率的提高叶绿素含量轻微下降.强光下的光合速率和气孔导度均高于弱光,不过随着强光波动频率增加,两者呈下降趋势.荧光诱导动力学的结果显示,尽管各处理间光系统Ⅱ(PSⅡ)最大光化学效率没有明显差异,但波动频率较大时黄瓜的PSⅡ的电子传递活性略有降低;而且增加强光波动频率还导致光系统Ⅱ天线转化效率(Fv′/Fm′)明显降低和非光化学猝灭(NPQ)大幅增加.此外,强光下黄瓜的酶促抗氧化系统的主要酶活性高于弱光,但波动光频率提高能够降低其活性.因此,提高波动光的频率不仅导致黄瓜光合能力下降,还导致其主要抗氧化酶的活性降低,所以增强的热耗散可能是其应对波动光下过剩激发能的重要机制.此外,本文还对黄瓜适应波动强光和稳态强光的差异进行了讨论.Plants are often exposed to fluctuating light under natural conditions, but the effects of changing frequency of fluctuating light on photosynthesis and related mechanism are not clear. In order to study the photosynthetic mechanism under fluctuating light, the changes of morphology, chlorophyll content, gas exchange, chlorophyll a fluorescence and enzymatic antioxidant system were compared in cucumber seedlings grown under different light regimes. Results showed that the plant height, biomass, leaf area and specific leaf weight were significantly higher under high light treatment(T1, T2 and T3) than those of low light treatment(T4), and these values decreased with the frequency of fluctuating light increasing(T2 and T3). Compared with low light treatment, the total chlorophyll content decreased under high light, and enhancing the frequency of fluctuating light resulted in the decrease in the chlorophyll content slightly. Photosynthetic rate and stomatal conductance in leaves grown under high light were higher than those under low light, and the levels of both parameters decreased slightly with the changing frequency of fluctuating light increasing. The results of chlorophyll a fluorescence induction kinetics showed that although there was no significant difference in the maximum quantum yield of photosystem II(PSII), the electron transport activity of PSII in cucumber leaves decreased with the increase of the changing frequency of fluctuating light. Increasing the changing frequency of fluctuating light led to an obvious decrease in antenna conversion efficiency of PSII(Fv′/Fm′) and rapid increase in non-photochemical quenching(NPQ). In addition, the activities of the major antioxidant enzymes in cucumber leaves grown under high light was higher than that under low light, yet the increase of the frequency of fluctuating light reduced their activities. Therefore, enhancing the changing frequency of fluctuating light leads to a decrease in photosynthetic rate and the activities of major antioxidant enzymes in

关 键 词：强光 波动光 光合作用 叶绿素荧光 光破坏防御 

分 类 号：S642.2[农业科学—蔬菜学]