Some Properties of Mitochondria from Irradiated Tomato Fruit

SUMMARY — Homestead tomato fruit were irradiated with 300 Krad of 60 Co gamma rays at three stages of maturity–mature‐green, 2 and 6 days from color break. Though oxygen consumption by mitochondrial preparations was greatly suppressed immediately after irradiation it increased to a maximum during the following 2 days and then declined similarily to nonirradiated fruit. Oxygen consumption was reduced considerably during ripening of the nonirradiated and irradiated 6 day breakers. Mitochondria from irradiated fruit exhibited lower P/O ratios than from nonirradiated fruit. A considerable reduction was less pronounced with the 2 and 6 day breakers. In vitro irradiation of mitochondrial preparations indicated no differences in activity with doses up to 100 Krad, but at 150 and 300 Krad, the activity decreased by 50 and 90%, respectively.