FRUIT-GROWTH AND BIOMASS ALLOCATION TO THE FRUITS IN CUCUMBER .1. EFFECT OF FRUIT LOAD AND TEMPERATURE

Cucumber plants were grown at 18-degrees-C or 25-degrees-C and with four intensities of fruit removal to analyse the effects of temperature and the number and weight of fruits on fruit growth and biomass allocation to the fruits. Increasing the number of fruits per plant increased the total fruit growth at the expense of the vegetative growth. The daily biomass allocation to the fruits showed a saturation type relationship with the total fruit weight on a plant. With the same number or weight of fruits on a plant, the biomass allocation to the fruits was greater at 25-degrees-C than at 18-degrees-C. When the number of fruits on a plant was not manually restricted, temperature had only a slight effect on the biomass allocation because there were less fruits on a plant at 25-degrees-C than at 18-degrees-C. With increasing number of fruits per plant or decreasing temperature the growth rate of the individual fruits decreased, resulting in an increase in the growing period from anthesis until harvest of the individual fruits. The dry-matter percentage of the fruits decreased with increasing number of fruits on a plant and with increasing temperature. The fruit fresh weight production increased with increasing temperature, but fruit dry weight production was hardly affected.