Putrescine accumulation in wounded green banana fruit

The concentrations of putrescine (Put) and ethylene, and the effects of biosynthesis inhibitors on the production of polyamines and ethylene were examined in wounded pulp tissue of green banana fruit. The Put concentration in the sliced banana fruit, and the arginine decarboxylase (ADC, EC 4.1.1.19) activity increased with the increase of ethylene evolution. Difluoromethylarginine (DFMA) suppressed Put accumulation by 72% while difluoromethylornithine (DFMO) had no effect on the Put content. Methylglyoxal bis(guanylhydrazone) (MGBG) decreased ethylene production and suppressed Put accumulation. Aminooxyacetic acid (AOA) and norbornadiene (NBD) also depressed Put accumulation. These findings suggest that ethylene produced in the wounded pulp tissue affects the induction of ADC and the accumulation of Put.