GUM FORMATION BY METHYL JASMONATE IN TULIP SHOOTS IS STIMULATED BY ETHYLENE

The promotive effect of methyl jasmonate (JA-Me) on the induction of g um in tulip shoots (Tulipa gesneriana L. cvs. Gudoshnik and Apeldoorn) was studied in the presence of ethylene. Gum formation in the stem an d the basal part of the leaves was induced by JA-Me (1% w/w in lanolin ) and stimulated strongly by the simultaneous application of 1 or 5 mM 1-aminocyclopropane-1-carboxylic acid (ACC). JA-Me at a concentration of 0.1% did not induce gum, but that together with ACC at a concentra tion of 1 or 5 mM induced it substantially. Although JA-Me stimulated ethylene production substantially in the stem of intact tulips, etheph on (1% w/w) or ACC (1 or 5 mM) did not induce gum formation in tulip s hoots. JA-Me induced gum formation in tulip shoots even in the presenc e of aminooxyacetic acid or cobalt ions. Moreover, gum formation was a lso observed in the cut shoot applied with JA-Me as a solution at conc entrations of 0.23 mM or more. These results strongly suggest that JA- Me is required for gum formation in tulip shoots, and ethylene probabl y makes the tissues of shoots sensitive to JA-Me.