EFFECT OF METHYL JASMONATE ON ETHYLENE BIOSYNTHESIS AND STOMATAL CLOSURE IN OLIVE LEAVES

The influence of methyl jasmonate (MeJA) on ethylene production and 1-aminocyclopropane-1-carboxylic acid (ACC) and malonyl-ACC (MACC) contents in olive leaf discs and detached leaves was investigated. In leaf discs, both ACC content and ethylene-forming enzyme (EFE) activity were clearly stimulated by 45 muM MeJA. In detached leaves MeJA treatment increased ACC content with no clear increase in ethylene production. When detached leaves were incubated with MeJA (45 muM) and ACC (1 mM), the total endogenous ACC content was significantly lower than that of leaves incubated only with ACC (1 mM). These data could be explained on the basis that MeJA caused stomatal closure, and hence reduced ACC uptake.