The Pattern and Control of Phospholipid Metabolism in Wheat Aleurone Tissue

Abstract

Phospholipid synthesis in wheat aleurone tissue was found to be induced by imbibition. Radiotracer experiments using [Me-¹⁴C]choline precursor showed that the synthesized phospholipid was located in the microsomal fraction of the tissue. The most active period of phospholipid synthesis was during the first day of germination before 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 increased the rate of phospholipid breakdown. Abscisic acid (ABA) also induced phospholipid breakdown, and ABA did not inhibit the GA₃-induced breakdown. The relationship of phospholipid synthesis and membrane formation to the induction of hydrolase production by GA₃ is discussed.