Abstract: Using sodium nitroprusside (SNP) as a nitric oxide (NO) donor, the effects of different concentrations of nitric oxide treatment on physiological index of post-harvest strawberry (Fengxiang), including ethylene production rate, respiration rate, vitamin C (Vc), soluble protein, the rate of water loss, rot and relative conductivity, and the activities of relevant enzymes from the fruit, including SOD, CAT and POD, were investigated. The results showed that NO resulting from 5 μmol·L-1 SNP aqueous solution obviously inhibited ethylene production rate, respiration rate, the increase of rot rate and relative membrane permeability and delayed the decrease of the ratio of soluble solids/acids, vitamin C and soluble proteins. The activity of CAT obviously increased during the storage and the decrease of activity of SOD was delayed during the later storage for the strawberry treated with 5 μmol·L-1 SNP aqueous solution. But the activity of POD from strawberry after treatment was lower than that of control fruit. NO resulting from 10 μmol·L-1 SNP aqueous solution injured slightly the fruit. The effect of NO from 1 μmol·L-1 SNP aqueous solution on delaying senescence of strawberries was not distinct. These have proved the relationship between inhibition of NO on senescence of fruit, and opened up the mechanism that NO protected the structural integrity of cell wall.

Key words: Strawberry (Fragaria ananassa), Sodium nitroprusside, Nitric oxide, Post-harvest, Physiological index