NONINVOLVEMENT OF ACC AND ACC OXIDASE ACTIVITY IN PEPPER FRUIT RIPENING

Pepper of the variety California shows sigmoid-type growth curves and changes of colour, which are characteristic of the fruit reaching maturity, when it has practically reached full size. Respiratory activity is high a few days after fruit-set and then falls progressively. Ethylene production and 1-aminocyclopropane-1-carboxylic acid (ACC) levels remain low throughout fruit development and maturation, while ethylene-forming enzyme (EFE) activity gradually falls throughout the development. We show that treatment with propylene has no effect on the post-harvest maturation of pepper, although treatment with silver thiosulphate (STS) increases respiratory intensity and ethylene production due to the stress caused which, in turn, causes an increase in ACC levels after treatment. All these results lead to the conclusion that pepper behaves like a non-climacteric fruit during maturation, and that maturation is not regulated by ethylene.