Glycerolipid Synthesis in Avena Leaves during Greening of Etiolated Seedlings IV. Effect of Light on Fatty Acid Desaturation

Etiolated Avena sativa L. leaves were fed with l-¹⁴C]acetatefor 20 h in the dark and labeled fatty acids in glycerolipidswere chased during 24 h in the light (greening condition) orin the dark, to determine the light effect on the fatty aciddesaturation. Oleate decrease in phosphatidylcholine was thesame in the light and in the dark, showing that oleate desaturationis independent of light (or greening). Linoleate desaturationin galactolipids, especially in monogalactosyl diacylglycerol,was enhanced by light and palmitate desaturation to hexadecenoatein phosphatidylglycerol was strictly light-dependent. (Received May 11, 1983; Accepted August 16, 1983)