THE LONG-TERM EFFECT OF COLD ON THE METABOLISM OF WINTER-WHEAT SEEDLINGS .2. COMPOSITION OF FATTY-ACIDS OF PHOSPHOLIPIDS

1. In seedlings of winter and spring (controls) wheat the changes in t he composition of phospholipid fatty acids induced by long-term cold t reatment and by subsequent adaptation to 20-degrees-C are examined. 2. In both genotypes grown at 2-degrees-C, as compared to 20-degrees-C, linolenic acid (18:3) was increased and oleic (18:1) and linoleic acid s (18:2) decreased in content, and the ratio of 18:3/18: 2 also increa sed. 3. In the winter variety, during growth at 20-degrees-C, changes in 18:3/18:2 ratio were small but at 2-degrees-C, after a cold treatme nt sufficient for vernalization (56 days), rapid decrease in the ratio was observed. This change however, did not influence the double bond index (DBI). 4. After 4 days adaptation to 20-degrees-C winter wheat s eedlings, subjected to prior cold treatment, retained a fatty acid com position resembling that formed in the cold. In the spring variety 2 d ays adaptation to 20-degrees-C caused changes in fatty acid compositio n characteristic for seedlings grown at 20-degrees-C.