THE EFFECT ON CD CONTENTS AND ETHYLENE BIOSYNTHESIS IN TOMATO PLANTS OF ADDING CADMIUM SULFATE TO SOIL

An experiment was carried out with increasing concentrations of Cd in soil on tomato (Lycopersicon esculentum Mill.) plants. The Cd contents of soil and in tomato roots, leaves and fruit have been determined during the growing cycle. The effect of Cd on ethylene production has been investigated by monitoring hormone biosynthesis in whole fruit during different ripening stages. Furthermore, 1-Aminocyclopropane-1-carboxylic acid (ACC) content, ACC synthase activity in vitro and Ethylene-Forming Enzyme (EFE) activity in vivo have been studied after incubation of fruit discs at different Cd concentrations. A clear relationship existed between Cd in the soil and its concentration in the leaves. Roots showed the highest Cd concentration, whereas fruit did not accumulate the element. Ethylene evolution of whole fruit was not affected by the Cd treatment. High Cd concentration (80 ug mL-1) induced a slight increase of EFE activity in fruit discs.