Response of Endogenous Nitric Oxide and Jasmonate Acid to Low Temperature Stress in Young Loquat Fruits

Container seedlings of three-year-old loquat were treated with Nitric oxide (NO) production inhibitors L-NAME, NaN₃ and NO scavenger cPTIO to investigate the effects of endogenous NO and Jasmonate acid (JA) content on young loquat (Eriobotrya japonica cv. Zaozhong No.6) fruits under low temperature stress and determine the signal transduction relationship between endogenous NO and JA.Results showed that induced the endogenous NO and JA content of young loquat fruits to increase by low temperature stress.NO scavenger and NO production inhibitors treatment inhibited the activities of CAT,POD and SOD.Meanwhile,NO scavenger and NO production inhibitors treatment increased the contents of H₂O₂ and MDA in young loquat fruits under low temperature stress,which enhanced lipid peroxidation.The injury of young loquat fruits was aggravated by low temperature stress.NO scavenger and NO production inhibitors treatment decreased the activities of LOX and AOS in young loquat fruits under low temperature stress,and the pathway of JA biosynthesis was restrained.The endogenous JA content of young loquat fruits was closely related to the changes in endogenous NO content.There may be a signal cross between NO and JA in response to low temperature stress in young loquat fruits.