Alteration of ethylene synthesis in cucumber seedlings by triadimefon

Abstract

Etiolated cucumber seedlings grown from seeds pretreated with 5 μg∙mL−1triadimefon (1-(4-chlorophenoxy)-3,3 dimethyl-1-(1H-1,2,4-triazol-1-yl)-2-butanone) exhibited a marked reduction in both ethylene (C2H4) production and endogenous 1-aminocyclopropane-1-carboxylic acid (ACC) levels. Most of this reduction could be accounted for by a twofold drop in C2H4 production and fivefold drop in ACC content of root tissue. Roots of control seedlings efficiently converted exogenous ACC to C2H4, but the ability of triadimefon-treated roots to convert ACC to C2H4 was impaired. However, triadimefon-treated shoots and cotyledons were nearly twice as efficient in utilizing exogenous ACC and metabolizing it to C2H4 as control tissues.