气体交换与荧光同步测量估算植物光合电子流的分配  

Discussion on simultaneous measurements of leaf gas exchange and chlorophyll fluorescence for estimating photosynthetic electron allocation

作　　者：康华靖[1,2,3,4] 李红[4] 陶月良[5] 张海利[4] 权伟[4] 欧阳竹[1,2,3] 

机构地区：[1]中国科学研究院地理科学与资源研究所生态网络观测与模拟重点实验室,北京100101 [2]中国科学研究院禹城综合试验站,北京100101 [3]中国科学研究院研究生院,北京100049 [4]温州科技职业学院,温州325006 [5]温州大学生命与环境科学学院,温州325026

出　　处：《生态学报》2015年第4期1217-1224,共8页Acta Ecologica Sinica

基　　金：国家高技术研究发展计划(863计划)项目(2013AA102903);中国科学院地理科学与资源研究所"一三五"战略科技计划项目(2012ZD004);浙江省教育厅项目(Y201327619)

摘　　要：光合电子流分配是植物光合控制的一个重要环节。然而,传统电子流分配的计算方法存在诸多问题尚未引起人们的注意,如:(1)低估了光呼吸每释放一个CO2分子所消耗的电子数;(2)混淆了相对电子传递速率和绝对电子传递速率;(3)忽略了除碳同化和光呼吸外的其他电子流分配途径;(4)难以准确获取光下暗呼吸速率值,从而导致碳同化电子流(JC)及光呼吸速率(Rp)的不准确估算等。以小麦和大豆气体交换与荧光同步测量数据为例,结果表明大豆电子传递速率与碳同化两者对光强的响应一致性较好,同时达到最大值;而小麦的一致性相对较差,说明电子传递速率和碳同化并非完全一致,推测认为有可能与作物对同化产物输出的模式不同有关。通过光呼吸速率换算出的电子流(12×Rp)与实际测量电子流(ΔJO)之间存在较大的差异;另外,传统方法估算出的光呼吸速率(估算值)与光呼吸测量值之间也存在较大差异,分析认为这主要是由于绝对光合速率与相对电子传递速率之间差异造成。The thylakoid electron （ e- ） transport chain in plant chloroplasts is pivotal in coordinating the fluctuating supply of absorbed light energy with the varying demands of the photosynthetic metabolism. Photosynthetic electron allocation plays a key role in regulation of the photosynthetic metabolic processes. However, according to the bioch-emical process, there are some deficiencies in the current method ： （ 1 ） the electron number required for one oxygenation cycle was underestimated ; （2） the relative electron transport rate and the absolute electron transport rate were confused ; （ 3 ） some electrons via PS 11 were used to CO2 assimilation and photorespiration, whereas others associated with electron-consuming processes （e.g. O2 acceptor cycle or water-water cycle） were ignored; （4） mitochondrial respiration in the light （Ra） was difficult to obtain, which led to inaccurate estimation of carboxylative reaction electron flow （ Jc ） and photorespiration rate （ Rp ）. Simultaneous measurements of leaf gas exchange and chlorophyll fluorescence for wheat and bean were measured in this study. The results revealed that the electron transport rate and CO2 assimilation synchronously reached the maximum values through fitting the rapid light curves and light response curve of plant photosynthesis in bean, but not in wheat. It＇s concluded that the difference seemed to be attributed to assimilation product output pattern. The difference of the electron allocations between the calculated values from photorespiration rate （12 × Rp ） and the measured ones （△J0 ）, and the difference of photorespiration rate between the estimation by traditional method （Eq.5） and the measurement, were all demonstrated that the difference between the relative electron transport rate and absolute electron transport rate.

关 键 词：气体交换 荧光 电子流分配 碳同化 光呼吸 光下暗呼吸 

分 类 号：Q945.11[生物学—植物学]