Carbon Translocation in the Tomato: Effects of Fruit Temperature on Carbon Metabolism and the Rate of Translocation1

Abstract

The effects of fruit temperature on the rate of carbon translocation and on the contents of the major carbon metabolites in the experimental fruits were investigated. Carbon import, which was inversely proportional to fruit size, was inhibited by fruit cooling (5°C and enhanced by fruit warming (35°C) when compared with controls (25°C); furthermore, there was net export of carbon from the largest cooled fruits. The carbon translocation rates were related both to the rates of accumulation or depletion of starch and insoluble residue and to the concentration of sucrose in the fruit. The possible dependence of the rate of translocation on a gradient of sucrose concentration between source and sink is discussed.