Leaf lipids of Ribes nigrum: a plant containing 16 : 3, alpha-18 : 3, gamma-18 : 3 and 18 : 4 fatty acids

The glycerolipid composition of Ribes nigrum (blackcurrant) leaves was dete rmined. The total fatty acid composition was unusual in that alpha -linolen ic acid (alpha -18:3) occurred together with cis-7,10,13-hexadecatrienoic a cid (16:3) and lower amounts of stearidonic acid (18:4) and gamma -linoleni c acid (gamma -18:3). Monogalactosyldiacylglycerol contained the highest pr oportion of 16:3 with less in digalactosyldiacylglycerol. gamma -18:3 and 1 8:4 were present in all lipids and 18:4 was always greater than gamma -18:3 . The highest percentages of gamma -18:3 and 18:4 were in phosphatidylcholi ne, but phosphatidylglycerol was particularly low in these acids. In summar y, the lipid composition was largely typical of 16:3 plants but there was a minor contribution typical of 18:4 plants. The possibility of three pathwa ys for glycolipid biosynthesis is discussed.