Regulation Mechanism Of Nitric Oxide On The Ripening And Senescence In Fruit Of Strawberry And 'Feicheng' Peach

Using sodium nitroprusside (SNP) as a nitric oxide (NO) donor, the effects of different concentrations of NO 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 fruits, including SOD, CAT and POD, were investigated.The peach fruits (Prunus persica (L.) Batsch., cv. Feicheng) were fumigated with 0,5,10 and 15μl L-1 NO for 2 h, then stored at 5 and 27℃. The effects of NO on ethylene biosynthesis and lipoxygenase (LOX) activity were studied. The cell wall enzymes and cell wall changes of peach fruits were also detected. Changes in the compositions of the total polar lipid (TPL), phospholipid (PL), monoacylglycerol (MG), diacylglycerol (DG), triacylglycerol (TG) and free fatty acid (FFA) were examined. The action mechanisms of NO to provide basic data for storage of Feicheng peaches with NO were also discussed.The results showed that NO resulting from 5μmol L-1 SNP aqueous solution obviously inhibited the increase of rot rate and relative membrane permeability and delay 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 5μmol L-1 SNP aqueous solution. But the activity of POD from strawberry after treatment was lower than that of control fruits. The activity of PME, cellulase, PPO and LOX could be significantly inhibited in the fruits treated by 5μmol L-1 SNP aqueous solution. The effect of NO from 1μmol L-1 SNP aqueous solution on delaying senescence of strawberries was not distinct. NO resulting from 10μmol L-1 SNP aqueous solution injured slightly the strawberry fruits. A mechanism that proper concentration of NO could inhibit senescence of strawberry fruits by the way of affecting the activities of softening enzymes was opened out. This also proved that NO took on dual biological effects on senescence of fruits. 5μmol L-1 SNP significantly inhibited ethylene production, the activity of ACS and ACO activities. Especially, the activity of ACS in strawberry was...