PUTRESCINE CONTROL OF PEROXIDASE-ACTIVITY IN THE INDUCTIVE PHASE OF ROOTING IN POPLAR SHOOTS IN-VITRO, AND THE ADVERSARY EFFECT OF SPERMIDINE

Poplar shoots raised in vitro rooted by 100 % in the presence of an au xin while in its absence they did not root. Putrescine, however, and t he inhibitor of spermidine synthase, cyclohexylamine (CHA), which favo urs putrescine accumulation, were able to promote up to 40 % rooting i n the absence of auxin. The inhibitory effect of aminoguanidine (AG), which inhibits diamine oxidase, indicated that the catabolic pathway o f putrescine was involved in the rooting process. The inductive phase of rooting in poplar shoots was characterized by an increase of peroxi dase activity followed by a rapid decrease. Putrescine and CHA favoure d this variation. AG and spermidine had adversary effects.