CHARACTERISTICS OF THE INDUCTION OF THE ETHYLENE BY CADMIUM IN DETACHED RICE LEAVES

The effect of cadmium on the production of ethylene in detached rice l eaves was investigated. Cadmium promoted the production of ethylene in detached rice leaves under both light and dark conditions. Cadmium st imulated the production of ethylene shortly after its application. The stimulatory effect of cadmium resulted from the enhancement of the co nversion of 1-aminocyclo-propane-1-carboxylic acid to ethylene. Cadmiu m also induced the accumulation of putrescine and spermine in detached rice leaves. Both D-arginine and alpha-methylornithine, inhibitors of the biosynthesis of putrescine, reduced the level of putrescine and t he production of ethylene induced by cadmium. Since polyamines were fo und to promote the production of ethylene in detached rice leaves (Che n et al. Plant Cell Physiol. 32: 813-817, 1991), the accumulated polya mines may also be responsible, at least in part, for the observed incr ease in production of ethylene in cadmium-treated rice leaves.