Effects of Lipids and Their Related Compounds on the Chloroplast Functions

Abstract

Effects of lipids and their related compounds on the chloroplast functions were investigated. Whole lipids, i.e. methyl linolenate, monogalactosyldiglyceride, and lecithin induced only a slight effect on the photochemical activities; electron transport, H⁺ uptake, and cyclic photophosphorylation. Lecithin alone stimulated significantly O₂ evolution. On the con-trary, the lipid-hydrolysis products, i.e. linolenic acid, monogalactosylmonoglyceride, and lysolecithin caused a strong inhibition of all the photoactivities tested. They showed two different modes of inhibition, which arise probably from a situation whether the lipids affect coupling factor or not besides the membrane part in thylakoid. Peroxidized methyl linolenate and α-tocopherol were also examined and the effect of lipid oxidation was discussed.