菠菜叶绿体光系统Ⅱ反应中心D1／D2／cyt　b559长寿命荧光组分的来源  

Origin of Long-Lifetime Fluorescence Components for Photosystem Ⅱ Reaction Center D1/D2/cyt b599 Complex from the Chloroplasts of Spinach

作　　者：于振宝[1] 匡廷云[1] 唐崇钦[1] 彭德川[1] 汤佩松[1] 李成勇[1] 

机构地区：[1]中国科学院植物研究所光合室,中国科学院动物研究所生物膜与膜工程国家重点实验室

出　　处：《植物生理学报（0257-4829)》1994年第1期17-22,共6页Acta Phytophysiologica Sinica

摘　　要：通过多频相位调制法测得菠菜叶绿体光系统Ⅱ（ＰＳⅡ）反应中心Ｄ１／Ｄ２／ｃｙｔｂ５５９复合物的荧光衰减包括４个组分，其寿命分别大约为１、６、２４和７３ｎｓ，所占整个荧光的比例依次为５％、３４％、３５％和２６％。而寿命为６ｎｓ的组分来源于与电荷分离不相关的ｃｈｌａ分子，寿命为１ｎｓ的组分所占的比例很小，其来源不清楚。其中两个长寿命组分都与样品的光化学活性相关，但彼此又是不相关的，很可能来源于电荷分离后的两个不同的重组过程。Time-resolved fluorescence measurements by multi-frequency phasemodulation method suggest that D1/ D2/cyt b559 photosystem Ⅱ reaction center cmplex has four fluorescence components with lifetimes of about 1. 0, 6. 0, 24 and 73 ns, which form 0. 05, 0. 34, 0. 35 and 0. 26 respectively of the total fluorescence yield (Table 1). The 6. 0 ns fluorescence component corresponds to chlorophyll a which is energctically uncoupled fromcharge separation. The origin of the 1. 0 ns comPOnent, which accounted for a very small fraction, remains nuclear.The effects of various treatments on fluorescence decay have been studied.Light treatment caused the fractional yields of two long-lifetime components (24 and 73 ns ) to decrease at samerate. (Fig. 2). Unfolding of the reaction center complex in the presence of 3 mol urea/L caused similar effects (Table 2 ). These results suggest that both of the two long-lifetime components are related to the photochemicalactivities of the reaction center. The result about the PH effect on fluorescence decays shows that, from PH 7. 2 to pH 3. 5, the 73 ns comPOnent is very sensitive to pH value, while the 24 ns component is not (Fig. 3). The difference implies that the two long-lifetime comPOnents may come from different photochemical processes, the 24 ns component from the recombination of P680+. Pheo-, and the 73 ns component from that of Ch1 670+. Pheo-.

关 键 词：菠菜 光合系统 叶绿体 反应中心 

分 类 号：S636.101[农业科学—蔬菜学]