Effects Of Exogenous Salicylic Acid On Pipening And Senescence Of Yali Pear And Whangkeumbae Fruit

Yali and Whangkeumbae pear were used as the expefiment materia,exogenous SA at different concentrations treated tree body one month before harvest,(Ommol/L, 0.02mmol/L,0.2mmol/L,2.0mmol/LSA).respiratory intensity and ethylene synthesis of two cultivars fruit had been studied on ripening and senescence,the inhibitory effect of SA on respiratory intensity and ethylene synthesis of two cultivars had also been research to reveal the regulation mechanism of SA on fruit ripening and senescence.The main results were as follows:1.Ethephon could improve the Yali pear fruit respiratory intensity during fruit ripening and senescence,treated used ethephon,the respiratory intensity higher than control,the respiratory intensity significantly increased of fruit,not significantly on Whangkeumbae pear.2.Different concentrations of exogenous SA could decreased the respiratory intensity of fruit on ripening and senescence.0.02mmol/L SA had the dramatic effect on decreased the respiratory intensity of Yali fruit,while 0.2mmol/L SA had the significant effect on reduced the respiratory intensity of Whangkeumbae fruit.3.Different concentrations of exogenous SA solution could decreased the ethylene production rate of fruit ripening and senescence.0.2 mmol/LSA significantly decreased the ethylene production rate of the two cultivars,0.02 mmol/LSA had the remarkable effect on decreased the ethylene production rate.4.Different concentrations of exogenous SA could decreased ACC content of Yali pear.treatment compared to control reached significant level,0.2 mmol/L SA was the optimal treatment.Different treatments reached significant level of Whangkeumbae pear. 0.02 mmol/L SA was the optimal treatment on inhibition,2.0 mmol/L SA treatment promote generation of the ACC content prophase,and then inhibitory effect seven days later.5.Different concentrations of exogenous SA could inhibit the activity of ACC oxidase and ACC synthase on Yali pear.0.02 mmol/L SA was the optimal treatment.While 0.2 mmol/L SA was the optimal treatment of Whangkeumbae pear.6.Different concentrations of exogenous SA solution could inhibit LOX activity.0.02 mmol/L SA was the optimal treatment of Yali and Whangkeumbae fruit;As to O₂^- content of fruit,0.2 mmol/L SA was the optimal treatment of Yali pear,2.0 mmol/L SA was the optimal treatment of Whangkeumbae pear prophase,0.02 mmol/L SA was the optimal treatment ten days later.7.Different concentrations of exogenous SA could improve SOD activity of Yali and Whangkeumbae fruit.0.2 mmol/L SA was the optimal treatment;0.02 mmol/L SA could improve POD activity,0.2 and 2.0 mmol/L SA could inhibit POD activity on Yali pear. while 0.2 mmol/L SA was the optimal treatment of Whangkeumbae fruit,improving POD activity.