The effect of methyl jasmonate on ethylene production and CO2 evolution in Jonagold apples

Abstract

Apples cv. Jonagold were harvested at the beginning of October and stored at 0°C until treatment between the beginning of December and the end of January. Methyl jasmonate (JA-Me) at the concentration of l,0, 0,5, 0,1, 0,05, and 0,01% in lanolin paste were applied to the surface ofintact apples. During five days from treatment, samples of cortex with skin (area about 2,0 cm²) were cut off at a depth of about 2 mm and used for determination of ethylene production, ACC oxidase activity and respiration determined as CO₂ evolution. The production of endogenous ethylene was highest at mid-January ( 100, 280, and 250 nl/g*h at December, mid-January, and the end of January, respectively). During December and at the beginning of January, JA-Me initially ( 1 -2 days after treatment) stimulated ethylene production and then the production was inhibited. The lower concentration of JA-Me caused initially the greater stimulation and then Iower inhibition of ethylene production. However, at the time of maximum production of endogenous ethylene (mid-January) and later. stimulatory effect of JA-Me disappeared. The effect of various concentrations and time of application of JA-Me on ACC oxidase activity had similar trend as endogenous ethylene production. Methyl jasmonate stimulated respiration and this effect was dependent on JA-Me concentration and independent on time of application. The metabolic significance of these findings is discussed.