INFLUENCE OF WATER-STRESS ON ABSORPTION, TRANSLOCATION AND PHYTOTOXICITY OF FENOXAPROP-ETHYL AND IMAZAMETHABENZ-METHYL IN AVENA-FATUA

The influence of water stress on the absorption and translocation of C -14-labelled fenoxaprop-ethyl and imazamethabenz-methyl in Avena fatua L. (wild oat) was studied. The phytotoxicity to A. fatua of both herb icides with a droplet application was also examined under water stress conditions. The absorption of both fenoxaprop-ethyl and imazamethaben z-methyl was seduced by water stress when the plants were harvested wi thin 24 h after herbicide application. Up to 48 h after the applicatio n, the translocation out of the treated lamina of both herbicides, bas ed on percentage of applied C-14, was reduced under water stress condi tions. When harvested 96 h after herbicide application, however, water stress no longer significantly affected the absorption and translocat ion of either herbicide. When the herbicides were applied as individua l droplets, water stress reduced the phytotoxicity of fenoxaprop-ethyl but not that of imazamethabenz-methyl. It is concluded that the chang es in herbicide absorption and translocation may not be the major phys iological processes associated with differential whole-plant response of A. fatua to fenoxaprop-ethyl and imazamethabenz-methyl under water stress.