Low Temperature-Induced GA(3) Sensitivity of Wheat : II. Changes in Lipids Associated with the Low Temperature-Induced GA(3) Sensisivity of Isolated Aleurone of Kite.

Exposure of isolated aleurone tissue from the wheat (Triticum aestivum) variety Kite which contains the Rht2 allele, to low temperature (5 degrees C) for 20 h prior to addition of exogenous GA(3), resulted in significant changes in the content of lipids, especially phospholipids. Significant low temperature-induced changes in both the head group and acyl contents of two phospholipids, phosphatidylcholine and phosphatidylethanolamine, were detected. More importantly, these changes displayed a very close temporal relationship with the low temperature-induced increase in GA(3) sensitivity. Further, this relationship was paralleled by a highly significant correlation between the changes in the phospholipids and the changes in alpha-amylase production. These results underline the possibility that the GA(3) receptor sites are membrane-based lipids.