LIPID-COMPOSITION OF ENVELOPES, PROLAMELLAR BODIES AND OTHER PLASTID MEMBRANES IN ETIOLATED, GREEN AND GREENING WHEAT LEAVES

Comparative studies of lipid composition were made on prolamellar bodies, envelopes and other plastid membranes separately extracted from etiolated, green or greening (intermittent or continuous light) wheat (Triticum sativum L.) leaves. The different membrane fractions were examined by EM. The major lipid was digalactosyldiglyceride in the envelopes and prolamellar bodies and monogalactosyldiglyceride in stroma lamellae and grana. Phosphatidylcholine represented 60% of total phospholipids in the envelopes, 30% in prolamellar bodies and 14% in grana. All types of envelopes had the same lipid proportions. For all lipids the lowest fatty acid unsaturation was always found in the envelope membranes. The relative amount of trans-.DELTA.3-hexadecenoic acid in the phosphatidylglycerol of envelopes increased from 4% (etioplasts) to an average of 15% (etiochloroplasts and chloroplasts).