叶绿素缺乏对大豆光系统Ⅱ和光能分配的影响

Effect of Chlorophyll-deficient on PSⅡ and Distribution Properties of Absorbed Light Energy in Leaves of Soybean

研究田间条件下大豆叶绿素缺乏突变体以及野生型叶片逐步展开过程中的叶绿素含量、气体交换、叶绿素荧光动力学等特性,并分析了二者在叶片展开过程中吸收光能分配的差异。结果表明:叶绿素缺乏导致突变体大豆有活性的PSⅡ反应中心数目减少,每个反应中心的光能吸收和激发能捕获增加,但是PSⅡ电子传递受阻,致使每个反应中心的激发能耗散增加。与野生型相比,突变体大豆叶片所吸收的能量中分配给热耗散的能量较多,而过剩的激发能较少;同时随着叶绿素含量降低,光合电子传递中向光呼吸分配的比例增大。

The chlorophyll contents, gas exchange and chlorophyll fluorescence kinetics were extensively studied in chlorophyll- deficient mutant soybean leaves and its wild-type from emergency to full expansion under field conditions. The difference of the absorbed light distribution between two soybean varieties during the development of leaves was also assessed. Resuits showed that chlorophyll deficient induced a decrease of PS Ⅱ reaction centers, and resulted in an increase of excited energy capture per active reaction centers. It also showed that PS Ⅱ electron transport was blocked apparently, and the energy dissipation increased per PS Ⅱ reaction centers. Compared with wildtype soybean,the mutant had less excitation energy and the fraction of absorbed light allocated to energy dissipation. Furthermore, with the deficiency of the chlorophyll content allocation of photosynthetic electron transport to photorespiration was enhanced.