Effect of high temperature on cell wall modifications associated with tomato fruit ripening

Abstract

Abstract Tomato fruit (cv. ‘Sunny’) were harvested at the mature green stage and kept for 4 days at either 21°C or 40°C, then subsequently stored at 21°C. Red color development was inhibited in heated fruit, as was softening. Fourteen days after treatment, heat-stressed fruit were twice as firm as the controls. The cell wall uronide content increased in heat-exposed fruit while remaining unchanged in samples stored constantly at 21°C. Heat treatment inhibited ripening-associated cell wall modification so that 14 days after treatment, stressed fruit contained only one-third the amount of soluble polyuronides that was present in the control fruit. Furthermore, the rate of loss of cell wall galactose and arabinose was reduced in heat-stressed tomatoes. Postharvest exposure of unripe tomato fruit to high temperature appears to reduce the rate of cell wall degradation, while the synthesis of polyuronide components continues normally.