Popis: |
Pretreatment of 3-day-old maize seedlings with spermidine induces an enhancement of ethylene production from roots compared to control tissues with no effect on 1-aminocyclopropane-1-carboxylate oxidase activity and 1-aminocyclopropane-1-carboxylic acid level, accompanied by a strong inhibition of root growth. Inhibitors of ethylene synthesis, cobalt chloride and aminoethoxy-vinylglycine, markedly inhibited ethylene production in both control and spermidine-pretreated roots. The decrease in ethylene production did not result in reversing the inhibition of root growth induced by spermidine. Results suggest that the stimulation of ethylene by spermidine, probably due to more available S -adenosylmethionine, is not responsible for the inhibitory effect of spermidine on root growth. This statement is substantiated by the ineffectiveness of silver thiosulfate, a known inhibitor of ethylene action, to remove spermidine-mediated inhibition of root growth. |