在两个品种大豆叶绿体膜中,Mg~(2+)诱导荧光改变与类囊体膜表面电荷的关系

用“冀北1号”和“丰收黄”两个品种大豆的叶绿体膜,测定了不同 Mg~(2+)浓度对它们的光诱导 chla 可变荧光及电泳速度的影响。虽然将这两种叶绿体膜悬于相同的低盐介质中,其光诱导可变荧光产率彼此不同,但它们的可变荧光产率与电泳迁移率则是彼此相关的,在这两种大豆的叶绿体膜中,Mg~(2+)诱导荧光产率增加和电泳迁移率下降的浓度曲线均呈现出类似的动力学变化。Mg~(2+)诱导上述两种现象所需要的最适浓度亦大抵相同。这些实验结果说明:Mg~(2+)诱导激发能在两个光系统之间分配的改变与其诱导类囊体膜表面静电性质的变化是密切相关的。文中讨论了膜表面蛋白质的羧基在 Mg~(2+)诱导效应中的可能作用。

Mg~(2+)INDUCED FLUORESCENCE CHANGE IN RELATION TO THYLAKOID SURFACE ELECTRIC CHARGE IN TWO VARIETIES OF SOYBEAN CHLOROPLASTS

The effects of Mg~(2+)concentration on chlorophyll a light-in-duced variable fluorescence and electrophoretic velocity of chloroplasts obtained from two varieties of soybean(Ji-pei No.1 and Feng-Shou Yellow)were recorded.The light induced vari- able fluorescence yield and the electropboretic mobility of two kinds of chloroplasts in the suspending medium containing low level of salt differs from each other.But, the fluorescence yield of chloroplast membranes from two varieties of soybean is relative to that of electrophoretic mobility.The pattern of kinetic change of Mg~(2+)induced va- riable fluorescence intensity is similar to that of electrophoretic mobility.The optimum concentrations of Mg~(3+)required for the effect on chlorophyll fluorescence and the ele- ctrophoretic velocity change are also similar.These results indicate that Mg~(2+)induced excitation energy distribution change between the two photosystems is intimately re- lated to Mg~(2+)-induced alteration of thylakoid membrane surface electrostatic property. The possible role of carboxyl group of proteins on Mg~(2+)-induced effects has been dis- cussed in this paper.