Amino acids in kiwifruit 2. Distribution of 14C-leaf photosynthate among free amino acids during fruit maturation

摘要

Abstract The incorporation of 14C-leaf photosynthate into the free amino acids of the maturing fruit and fruit stalk of kiwifruit (Actinidia deliciosa) was investigated. In February 14C in the fruit core was found mainly in glutamine, and in the inner and outer cortex in glutamine and aspartic acid. Higher amounts of radioactivity were found in aspartic acid of the outer cortex than in other tissues. Increasing amounts of radioactivity were apportioned to arginine in the core at the stem end of the fruit during a 48-h period. As the fruit matured, increasing amounts of radioactivity in the core were found in glutamic acid. In the fruit stalk, 14C was found predominantly in glutamic acid, glutamine, and aspartic acid. The results indicated that: (1) arginine is synthesised in situ in the fruit and fruit stalk; (2) asparagine is likely to be synthesised early in fruit development; and (3) glutamic acid, serine, γ-aminobutyric acid, and alanine are likely to be transported from the leaf to the fruit.