The Effect of Temperature and Carbon Metabolism on Sucrose Uptake by Detached Tomato Fruits

The effect of temperature on sucrose uptake, and changes inlevels of starch, hexoses and sucrose in detached tomato fruitswas used to investigate the role of the sink in regulation ofcarbon import. Sucrose uptake was lower at 5 °C and greaterat 40 °C than at 25 °C. Conversion of radioactive componentsto starch was lower at both 5 °C and 40 °C than at 25°C, while the levels of non-radioactive starch was similarat all three temperatures. There was a depletion of glucoseand fructose in fruits at 40 °C. Uptake of sucrose froman agar medium by detached tomato fruits was negatively correlatedwith initial sucrose content of the fruit. The results indicatethat carbon import by tomato fruits is largely determined bysucrose levels which can be affected by metabolic activity. Lycopersicon esculentum L., tomato, fruit, sucrose uptake, temperature, carbon metabolism