The Role of Electrical Potential in Light-Induced Swelling and Shrinkage of Thylakoid Membranes

Abstract

Light-induced conformational change of thylakoids was widely studied in the 60’,-70’s[l][2]. Recently, the curiosity to understand the regulatory process of photosynthesis in vivo[3] has led people to work on this topic again[4][5]. It has been demonstrated that the shrinkage of thylakoids is induced by ΔpK and osmotic movement of weak organic acids across thylakoid membrane[2][6]. However, it has not been reported hitherto that the electrical potential involves in the light-induced conformational change of thylakoids. Electrical potential formation of thylakoid membranes under light has been studied for many years[7]. But the regulation of photosynthetic electron transport by electrical potential was not identified until 80’s[8][9]. In this paper, we studied the effects of electrical potential on light-induced conformational change of thylakoids, and found that a decline of electrical potential will induce or increase the light-induced shrinkage of thylakoid in medium without or with weak organic acids.