Lipid Composition and Carbon Turnover of Wheat Leaf Oleosomes

Abstract

Oleosomes from wheat flag leaves consist mainly of triacylglycerols (50–60% by weight) and esters (15–40% by weight). Analysis of oleosome, leaf total and leaf wax lipids, and of the fatty acid composition of some individual lipid classes, indicated that there are at least two pools of triacylglycerols in the leaf and that oleosome lipids form a significant proportion of leaf total lipid. Only about 0.05% of the radioactivity incorporated by flag leaves treated with [¹⁴C]–CO₂ was found in the fatty acids of triacylglycerols and esters. Over a period of 48 h the amount of radioactivity in these fractions, as a fraction of the leaf total radioactivity, increased. This suggests that the oleosome lipids are not involved in the short-term storage of products of photosynthesis. The function of wheat leaf oleosomes remains to be identified.