Effects of Exogenous Sodium Nitroprusside on AsA-GSH Circulation Metabolism in Mitochondria of Young Loquat Fruits under Low Temperature Stress
The effects of exogenous nitric oxide donor SNP(sodium nitroprusside)on antioxidant systems in young loquat(Eriobotrya japonica Lindl.cv.Zaozhong No.6)fruit mitochondria under low temperature stress were investigated in this study.The antioxidant content and antioxidant enzyme activity of mitochondrion of young loquat fruits were determined after pretreated with different concentrations of SNP and cold stress under-3 ℃.The results indicated that the concentrations of hydrogen peroxide(H2O2)and malondialdehyde(MDA)of young loquat fruits treated with 0.2 or 0.5 mmol/L SNP were lower than those in the CK while the content of reduced glutathione(GSH)and ascorbate(AsA),the activities of ascorbate peroxidase(APX,EC 1.11.1.11),glutathione reductase(GR,EC 1.6.4.2),dehydroascorbate reductase(DHAR,EC 1.8.5.1)and monodehydroascorbate reductase(MDHAR,EC 1.6.5.4)were higher than those in the CK.However,the effect of higher concentrations of SNP(1.0 mmol/L)treatment on antioxidant capacity of young fruits was not obvious.Appropriate exogenous NO treatment enhanced the cold-resistant capacity of mitochondrion of young loquat fruits by raising the concentrations of GSH and AsA,the activities of APX,GR,DHAR and MDHAR,reducing the concentrations of H2O2 and MDA.And it reduced the damages that cells suffered from low temperature press,enhanced the cold-resistance capability of the young loquat fruits under low temperature stress.