In vitro effects of monoterpenes on chloroplast membranes.

A chloroplast preparation was extracted from squash (Cucurbita pepo (L.) var. Senator). Enrichment of intact chloroplasts was achieved by continuous free-flow electrophoresis. The addition of monoterpenes, detergent and free fatty acids changed the elecrophoretic separation pattern characteristically. Monoterpene-dependent degradation of envelope membranes could be prevented by addition of α-tocopherol prior to monoterpene incubation.Photosynthetic electron transport of photosystem II was completely inhibited by β-pinene, Triton X-100 and linolenic acid. Inhibition could be modulated by addition of α-tocopherol or lecithin (phosphatidylcholine) either before or after inhibition by monoterpenes and detergent.Percentage reconstitution of photosynthetic electron transport inhibited by β-pinene depended on light conditions and incubation time.