THE EFFECTS OF THE HERBICIDE QUINCLORAC ON SHOOT GROWTH IN TOMATO IS ALLEVIATED BY INHIBITORS OF ETHYLENE BIOSYNTHESIS AND BY THE PRESENCE OF AN ANTISENSE CONSTRUCT TO THE 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID(ACC) SYNTHASE GENE IN TRANSGENIC PLANTS

Reduction of shoot growth, leaf epinasty and chlorosis in young tomato plants (Lycopersicon esculentum Mill. cv. Hellfrucht/Fruhstamm) treat ed hydroponically with 10(-7) M of the herbicide quinclorac were parti ally compensated when the plants were simultaneously sprayed with sali cyclic acid or the oxime ether derivative PACME. Since salicyclic acid and PACME are known inhibitors of ethylene biosynthesis, it is sugges ted that this pathway is implicated in quinclorac action. Further supp ort for this hypothesis was obtained in experiments with transgenic to mato plants containing an antisense gene to 1-aminocyclopropane-1-carb oxylic acid (ACC) synthase in ethylene biosynthesis. When quinclorac w as applied via the root antisense plants showed reduced phenotypical a lterations compared to those of wild-type plants.