Effects of sulphur dioxide fumigation on lipid biosynthesis in pine needles

Abstract

Pine needle tissues were shown to incorporate acetate [1- 14C] into phospho-, galacto- and neutral lipids. The major incorporation of the label among these lipids was always in the phosphatidyl choline (PC) fraction. The amount of label among the other lipid fractions varied depending on the age and source of the needle tissues (lodgepole or jack pine). In general, the biosynthesis of these lipids was more efficient in the developing than in the fully developed tissues. Treatment of the needle tissues with either gaseous or aqueous SO 2 markedly inhibited their lipid biosynthesis. These effects were more pronounced in the developing than in the fully developed needles. Fumigation with gaseous SO 2 showed that SO 2 concentration and length of exposure determine the extent to which the lipid biosynthetic capacity of the tissues is affected. Lipid biosynthetic capacity was partially or completely recovered when plants were removed from the SO 2 environment. Plants exposed to moderate SO 2 concentrations (0.18–0.20 ppm) for a period of 24 hr recovered faster than those exposed to near lethal SO 2 concentrations (0.34–0.37 ppm) for only 1 hr.