Studies on Fruit Ripening 1. Comparisons of Ripening Parameters, Peroxidase Activity, and Peroxidase Zymograme of Normal and rin Mutant Tomatoes

Fruit of tomato (Lycopcrsicum esculentum Mill.) cv. Floradel and of an isogenic mutant rin harveted at mature-green stage were ripened at 21℃ and were measured their activity and zymograme of peroxidase at designated color stages. Ripening of Floradel tomatoes were appeared to follow a pre-determined patterns; peroxidase activity increased about three times when fruit color chranged from mature-green to breaker stage; zymograme of peroxidase changed dramatically during fruit ripening. Rin mutant did not induce peroxidase activity, respiration, and ethylene evolution; fruit color changed to yellow after 99 days; zymograme of peroxidase were not changed; isozyme b and i were not appeared in rin mutant when compared with Floradel cultivar. Failure in ripening of rin mutant is postulated that lack of some isozymes of peroxidase resulting unability to receive activator (s), then to activate peroxidase for ethylene synthesis.