Effect of Electron Beam Irradiation on Ripening and Ethylene Production of Tomato Fruits Harvested at Different Mature Stages

Abstract:

The goal was to study the effect of electron beam （e-beam） irradiation on postharvest ripening and storage quality of climacteric fruits. Tomato fruits harvested at green，pink and red stages of ripeness were exposed to 0，0.4，and 1.0 kGy e-beam irradiation by linear accelerator （10 MeV，10 kW），and held as shelf-life storage （20±1 ℃，50% RH） for 14 days. The red color index of tomato，ethylene production，expression of ACC synthetase （ACS2） gene and ACC oxidase （ACO1） gene，storage quality were measured termly. Our results indicated that：red turning of tomato skin was suppressed by e-beam irradiation in a dose dependent manner. The red color indexes were declined with irradiation dose increase. E-beam irradiation showed no significant effects on weight loss，wrinkling and decay of tomato fruits during shelf-life time of 14 days. The effects of e-beam irradiation on ethylene production，expression of ACS2 gene and ACO1 gene were varied with mature stages of harvested tomato fruits. For tomatoes harvested at green stage，production of ethylene and expression of ACS2 gene and ACO1 gene were inhibited by e-beam irradiation. For tomatoes harvested at red stage，production of ethylene was promoted by e-beam irradiation. But effects of e-beam irradiation on expression of ACS2 gene and ACO1 gene for tomatoes harvested at red stage were varied with irradiation dose，and the tomatoes irradiated by 1.0 kGy e-beam showed lower expression level of ACS2 gene and ACO1 gene.