Research On Thylakoid Membrane Protein Complexes Of Pisum Sativum L. By Photoinduction

Chloroplast is the main organelle of plant photosynthesis and light is an essential environmental factor which plays an important role in the development of chloroplast.Studying of the light-regulated kinetics of chloroplast development is meaningful for us to know the significance contribution of light to the photosynthesis.Furthermore,it could provide some implications for the improvement of the photosynthesis efficiency and the developmental prerequisite of the chloroplast in different crops. P.sativum was adopted as experimental material in this study.The developmental course of the chloroplast was controlled by treating the seedlings with intermittent light,continuous illumination and dark.By means of BN-PAGE and BN/SDS-PAGE,we studied the packing characteristics and the expression of membrane protein complexes during the developmental course of thylakoid.The main conclusions are as follows:Fifty circulations of intermittent light(2min illumination,98min dark) promoted the expression of the specific genes which contributed to the synthesis of corresponding proteins in the seedlings of P. sativum.However,these protein complexes were few and the molecular weights were small.With the increasing illumination for 2 h,4 h,8 h,12 h,24 h and 48 h,the synthesis of protein complexes increased gradually.Furthermore,the electron transporters were packing and the thylakoid membrane was maturing gradually after the illumination.The light-induced synthesis of the PSâ… complexes was fast and exhibited a high degree of integration.The synthesis of the LHCâ…¡exhibited a close relationship with the development of thylakoid membrane during the course of illumination.This process(development of thylakoid membrane) was regulated by the light signal tightly.With the increasing of illumination,the expression of all kinds of membrane proteins was regulated by the nuclear genes and the chloroplast genes jointly.Treated seedlings with dark(60 h) after continuous illumination(less than 36 h) led to the gradual degradation of the thylakoid membrane complexes.The PSâ… complexes which exhibited a high degree of integration were sensitive to light and hydrolyzed firstly and the LHCâ…¡was almost disappeared.The development of chloroplast which was stabilized after 36 hours of illumination and dark treatment could not hydrolyze the LHCâ…¡completely.Treated seedlings with 60 hours of illumination and 60 hours of dark did not influence the development of the thylakoid membrane which exhibited similar characteristics to the common seedlings.It indicated that dark did not affect the development of thylakoid membrane after 60 hours of illumination.Our results revealed that dark can influence the initial stage during the development course of thylakoid membrane,however,the synthesis of membrane proteins and the development of thylakoid membrane were gradually stabilizing with the increasing of illumination and were not regulated by the dark later.Our results indicated that the light plays a signaling role in the development course of chloroplast besides the role of energy.