METHYL JASMONATE VAPOR INCREASES THE DEVELOPMENTALLY CONTROLLED SYNTHESIS OF ALKALOIDS IN CATHARANTHUS AND CINCHONA SEEDLINGS

Shortly after germination,;alkaloids are rapidly synthesized in seedli ngs of both Catharanthus roseus L.G. Don and Cinchona ledgeriana Moens . The effect of low-level, atmospheric methyl jasmonate on this develo pmentally controlled process was studied. In both species, about 1 p.p .m. of methyl jasmonate vapor significantly enhanced alkaloid synthesi s during germination, resulting in a doubling of alkaloid content in s eedlings. Treatment with methyl jasmonate resulted in increased alloca tion of alkaloid precursors and in enhanced enzyme activities in alkal oid biosynthesis. The ability of methyl jasmonate to increase alkaloid biosynthesis decreased with age of the seedlings. Susceptibility of t he process to methyl jasmonate was confined to a narrow time interval where the developmentally regulated onset of alkaloid synthesis occurr ed. When methyl jasmonate was applied at rater developmental stages, i ts ability to enhance alkaloid content in the seedlings declined sharp ly.