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 matu rity, when it has practically reached full size. Respiratory activity is high a few days after fruit-set and then falls progressively. Ethyl ene 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 developm ent. We show that treatment with propylene has no effect on the post-h arvest maturation of pepper, although treatment with silver thiosulpha te (STS) increases respiratory intensity and ethylene production due t o the stress caused which, in turn, causes an increase in ACC levels a fter treatment. All these results lead to the conclusion that pepper b ehaves like a non-climacteric fruit during maturation, and that matura tion is not regulated by ethylene.