枇杷幼果内源一氧化氮和茉莉酸对低温胁迫的响应

以三年生抗寒性较弱的‘早钟6号’枇杷(Eriobotrya japonica Lindl. cv. Zaozhong No.6)容器苗为材料,采用一氧化氮合成酶抑制剂L-NAME、硝酸还原酶非专一性抑制剂NaN₃和一氧化氮清除剂cPTIO处理低温胁迫下的枇杷幼果,研究其处理对枇杷幼果内源一氧化氮(Nitric oxide,NO)和茉莉酸(Jasmonate acid,JA)含量的影响,探讨枇杷幼果内源NO与JA对低温胁迫的响应及其信号转导的关系。结果表明:低温胁迫可诱导枇杷幼果内源NO和JA含量增加,采用NO清除剂和合成酶抑制剂处理均抑制了低温胁迫下的枇杷幼果中过氧化氢酶(CAT,EC 1.11.1.6)、过氧化物酶(POD,EC 1.11.1.7)和超氧化物歧化酶(SOD,EC 1.15.1.1)的活性,使过氧化氢(Hydrogen peroxide,H₂O₂)和丙二醛(Malondialdehyde,MDA)含量增加,细胞膜脂的过氧化加剧,加重了低温胁迫对幼果的伤害,导致了幼果脂氧合酶(LOX,EC 1.13.11.12)和丙二烯氧化物合成酶(AOS,EC 4.2.l.92)活性下降,内源JA生物合成受阻。细胞内源NO变化与JA含量密切相关,它们在枇杷对低温胁迫的响应中可能存在信号交叉。

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.