Abstract
This study investigated causes of increased susceptibility to excess moisture injury during the fruit developmental stage compared with vegetative stage in tomato plants. Dry matter, distribution patterns of photosynthates and bleeding rate in tomato plants under transient waterlogged condition were investigated. After whole shoots of tomato were exposed to 13CO2 for 5 hours, the tomato plants were waterlogged for 43 hours. The waterlogged treatment did not affect the distribution of newly fixed carbon to the roots during either stage of the tomato plant. Only 2% of assimilates translocated to the roots during the fruit developmental stage under waterlogged condition. The bleeding rate was lower in both stages following waterlogged treatment. The bleeding rate per unit root dry mass was lower during the fruit developmental stage compared with that at the vegetative stage. Therefore, it is suggested that relatively low distribution rate of photosynthate to the root, which is natural during the fruit developmental stage, and the greater decline in root activity would be factors promoting increased susceptibility of tomato to excess moisture injury.
