Amino acids in the bleeding sap of the grapevine. I

Daily changes in the soluble nitrogen complement

Abstract

By two-directional paper chromatography the amino acid composition of the bleeding sap of Vitis vinifera L. cv. Vigne de Michel was determined, and their daily fluctuation followed during 7 days of the bleeding period, It was shown that the free amides and aminoacids composition changes quanti and qualitatively during the succesive days of exudation prior to the bud burst of the pruned plants. Glutamine, glutamic and aspartic acids, and eventually arginine, in that order, were the most abundant nitrogenous compounds. In addition, ten more amino acids were determined. The total soluble nitrogen content showed three peaks, one on the Ist, one on the 5th, and one on the 7th day (in increasing order). Such changes were in dependent of the daily exuded sap. In another cultivar, e.g., Malbeck, grown under different conditions, it was shown again that glutamine and glutamic acid were the dominant soluble N compounds.

The possible causes accounting for the daily changes observed were discussed.