Leaf senescence in a non-yellowing mutant of Festuca pratensis : III. Total acyl lipids of leaf tissue during senescence.

The lipid compositions of leaves from Festuca pratensis cv. Rossa (yellowing) were compared with those from a non-yellowing mutant, Bf 993. The leaves of Bf 993 contained a higher level of acyl lipids on both a fresh-weight and a dry-weight basis. Diacylgalactosylglycerol, diacylgalabiosylglycerol and phosphatidylinositol were relatively enriched in the Bf 993 mutant while phosphatidylcholine was relatively reduced. There were no differences in the fatty-acid compositions of individual lipids between the two varieties. During senescence, the lipids of cv. Rossa were progressively degraded over an 8-d period. In contrast little lipid degradation was observed in the Bf 993 mutant during the first 4 d. The results support the hypothesis that the slower senescence changes of the Bf 993 mutant may be due, in part, to an altered membrane lipid composition.