EFFECTS OF NOVEL OXIME ETHER DERIVATIVES OF AMINOOXYACETIC ACID ON ETHYLENE FORMATION IN LEAVES OF OILSEED RAPE AND BARLEY AND ON CARNATIONFLOWER SENESCENCE

New derivatives of aminooxyacetic acid were tested for their ability t o inhibit ethylene formation in higher plants. Treatments with {[(isop ropylidene)-amino]oxy -acetic acid-2-(methoxy)-2-oxoethyl ester, {[(is o-propylidene)-amino]oxy}-acetic acid-2-(hexyloxy)-2-oxoethyl ester or {[(cyclohexylidene)-amino]oxy}-acetic acid-2-(isopropyloxy)-2-oxoethy l ester reduced ethylene evolution by leaf discs of oilseed rape and d rought-stressed barley leaves. The new compounds delayed senescence of cut carnation flowers. The endogenous levels of 1-aminocyclopropane-1 -carboxylic acid (ACC) and its N-malonyl conjugate were also reduced i n the leaf discs of oilseed rape. This suggests that a step in the bio synthesis of ethylene, prior to the formation of ACC, is inhibited by these new compounds. A lag phase in response suggests that these compo unds have to be activated most likely by the production of metabolites with a free aminooxy group.