Low Temperature-Induced GA₃ Sensitivity of Wheat. IV. Comparison of Low Temperature Effects on the Phospholipids of Aleurone Tissue of Dwarf and Tall Wheat

Abstract

Low temperature effects on the phospholipids of F₆ Rht 3/rht 3 isogenic lines of wheat were studied. Significant low-temperature-induced (5°C) augmentation in the phospholipids of the dwarf selection were detected. More specifically, a 20 h-5°C preincubation enhanced considerably the levels of phosphatidylinositol, phosphatidylcholine and phosphatidylethanolamine in the aleurone tissue of the dwarf selection. In addition, these changes displayed a very close temporal relationship with the low- temperature-induced increase in gibberellic acid (GA₃) sensitivity. In the case of the tall selection, only the imbibition of water was required to initiate the synthesis of major phospholipids of its aleurone tissue and low temperature preincubation had no effect on either the phospholipids or their fatty acid constituents. These results are discussed in the light of the hypotheses that GA₃ receptor sites are membrane-based lipids and that the Rht gene causes an aberration in the phospholipid metabolism of the aleurone tissue which can be corrected by low temperature.