Effects Of Salicylic Acid On Respiratory Pathway Of Huang-guan Pear (P. Pyrifolia. Cv. Whangkeumbae)

Huang-guan pear(P,pyrifolia,cv.Whangkeumbae)were used as the experiment material with different concentrations of SA solution.The effects of SA on respiration had been studied.Measurement of respiratory intensity of respiration,content of superoxide anion,while respiratory intensity and activities of key enzymes were studied at Embden-Meyerhof-Parnas pathway(EMP),Tricarboxyfic-acid-cycle pathway(TCA), Phosphopentose pathway(PPP)and electron transport respiratory chain.Relationships among content of superoxide anion(O₂^?),respiratory intensity of each respiratory pathway and respiratory intensity of respiration were studied,relationships between each respiratory pathway and respiratory enzyme were investigated,which provides the theoretical foundation for change of nutrition components and storage of post-harvest fruit.The main results were as follows:1.SA at different concentration decreased the respiratory intensity of respiration of Huang-guan pear.SA at 0.02mmol/L and 0.2mmol/L had significant effect,respiratory intensity of respiration was decreased by 35%when it is treated with 2h,and rate of respiration was reduced by 45%when it is treated 24h.2.SA at different concentration decreased content of O₂^?of Huang-guan pear.SA at 0.02mmol/L and 0.2mmol/L had significant effect.A positive correlationship was found between content of O₂^?and respiratory intensity of respiration.3.The respiratory intensity of EMP,TCA,PPP was decreased significantly,and enzyme activities of Phosphohexoisomerase,succinic dehydrogenase, Glucose-6-phosphate dehydrogenase and 6-Phosphogluconate dehydrogenas with 0.02 mmol/L SA.The trend in respiratory intensity of EMP,TCA,PPP was coincided with the enzyme activities of EMP,TCA,PPP,and respiratory intensity of EMP,TCA,PPP was positive correlation with enzyme activities of EMP,TCA,PPP.4.SA at different concentration decreased the respiratory intensity of alternative pathway,while Cytochrome pathway was decreased and lower than that of control at 2h after the treatment,and then increased and higher than that of control at 6h and 10h after the treatment,but then decreased and lower than that of control,and SA at 0.02mmol/L had significant effect.Respiratory intensity of Cytochrome pathway was positive correlated with Cytochrome oxidase.5.SA at different concentration regulated of respiratory intensity of each glucose metabolism by enzyme activity of relevant-respiratory pathway,respiratory intensity of alternative way was regulated by respiratory intensity of EMP,TCA,PPP,while Cytochrome Pathway was regulated by activity of Cytochrome Oxidase.6.Huang-guan pear fruit discs were treated by Different concentrations of SA solution, rate of respiration was regulated by content of O₂^?,respiratory substrate,rate of EMP,PPP and alternative pathway.