The effects of nitrate on sprouting of grapevine buds and changes in amino acid concentration

Abstract

The effect of potassium nitrate (KNO3) on sprouting of dormant grapevine buds were examined. KNO3 clearly hastened bud sprouting when applied to the plant in the field and also to the cuttings of the branch in the laboratory. Free amino acids were extracted from the buds and stems and quantified during the process of sprouting with or without application of KNO3. The concentrations of total free amino acids in the buds and the stems more or less increased during the sprouting and the increases were promoted by exogenous application of KNO3. Major amino acids such as Gln, Glu, Arg, Pro and Ala changed characteristically during the process and were affected by application of KNO3. Gln decreased in the stems although it increased in the buds and the increase was accelerated with KNO3. However, Ala changed in the reverse manner. We discussed some probable enzymes relating to amino acid metabolism.