The Pattern and Control of Phospholipid Metabolism in Wheat Aleurone Tissue

Phospholipid synthesis in wheat aleurone tissue was found tobe induced by imbibition. Radiotracer experiments using [Me-¹⁴C]cholineprecursor showed that the synthesized phospholipid was locatedin the microsomal fraction of the tissue. The most active periodof phospholipid synthesis was during the first day of germinationbefore gibberellic acid (GA₃) responses were evident. GA₃ was,in fact, without effect upon the rate of phospholipid synthesis,but evidence is presented which indicates that the hormone increasedthe rate of phospholipid breakdown. Abscisic acid (ABA) alsoinduced phospholipid breakdown, and ABA did not inhibit theGA₃-induced breakdown. The relationship of phospholipid synthesisand membrane formation to the induction of hydrolase productionby GA₃ is discussed.