Free Methionine Levels in rin and Normal Isogenic Tomato Fruits Ripened in the Field or in Storage

Abstract

Free methionine levels in rin and normal tomato fruits were determined microbiologically. Similar levels (1750 mug/100 g fresh weight) for mature green fruits of both rin and a normal isogenic line suggest that the lack of ripening of rin fruits is not due to low methionine levels. Methionine levels of mature green rin and normal fruits were 1750 mug/ 100 g fresh weight. Normal fruits ripened either on or off the vine were 2860 and 2500 mug/100 g fresh weight, respectively. The rin fruits which were left on the plant or held in air at 20 C until soft and yellow were significantly lower in methionine than C(2)H(4)-treated rin fruits or any normal fruits. Harvested rin and normal fruits held at 20 C in continuously applied ethylene (10 mul/l) had higher methionine levels than comparable air controls; levels in treated rin fruits were significantly higher than those in normal fruits.