Respiratory activity and mitochondrial membrane associated with fruit senescence in postharvest peaches in response to UV-C treatment.

The effect of 3.0kJ/m(2) ultraviolet-C (UV-C) treatment on respiratory activity and mitochondrial membrane associated with fruit senescence in peach fruit stored at 20°C for 8days was investigated. UV-C treatment could reduce senescence development, as evidenced by higher fruit firmness due to inhibition of respiration rate via reducing succinic dehydrogenase and cytochrome C oxidase activity. Meanwhile, the activities of superoxide dismutase, catalase and ascorbate peroxidase in the UV-C-treated fruit were much higher than those in control fruit, resulting in lower levels of superoxide radicals (O2(-)) and hydrogen peroxide (H2O2). In addition, this treatment maintained a higher level of mitochondrial membrane fluidity and inhibited opening of mitochondrial permeability transition pore. Our results suggest that the induction of antioxidant enzymes to scavenge O2(-) and H2O2 by UV-C treatment was associated with the maintenance of mitochondrial membrane integrity, which also played an important role in senescence retardation in peach fruit.