The growth of young tomato fruit. I. Effects of temperature and irradiance on fruit grown in controlled environments

Abstract

The influence of temperature and irradiance on the expansion of young tomato fruit grown in controlled environment cabinets was measured using displacement transducers. Changes in growth rate were assessed at 20 min intervals over several days and related to changes in irradiance, radiation integral and temperature. The expansion rate of fruit was most closely related to temperature but the relationship was influenced by changes in water status and less so by the rate of concurrent net photosynthesis. Irradiance had effects on growth rate both through changes in plant water status, probably due to changes in transpiration rate and, when radiation integrals were low, through assimilate supply. However, in most conditions, concurrent photosynthesis appeared not to limit fruit expansion rate because plants had sufficient reserves to maintain a high fruit growth rate for at least 20 h after darkening.