NO缓解玉米幼苗盐胁迫伤害的生理机制

Physiological Mechanism for Nitric Oxide Relieving Growth Inhibition of Maize Seedling under Salt Stress

以玉米幼苗为材料,通过NO的供体硝普纳(SNP)的合成抑制剂L-NAME和NaN3、清除剂cPTIO组合处理,分析外源NO和IAA对盐胁迫下玉米幼苗生长,以及NO对盐胁迫下玉米幼苗叶片和根尖IAA含量、IOD和POD活性的影响,以探讨NO与IAA在提高植物抗盐性中的关系。结果表明,盐胁迫下,SNP和IAA均能显著促进玉米幼苗株高、主根长和侧根数的增加;SNP能显著提高玉米幼苗叶片和根尖IAA含量,降低IOD和POD活性;L-NAME和NaN3及cPTIO均能有效减弱SNP诱导的IAA含量的增加。由此可见,在盐胁迫条件下,NO信号可能位于IAA信号的上游,它通过促进玉米幼苗內源IAA的积累缓解盐胁迫对其生长的抑制。

Using maize seedlings as material,the effects of sodium nitroprusside（SNP,an exogenous nitric oxide donor）and indole acetic acid（IAA）on growth of maize seedlings as well as the effects of SNP on IAA content,IAA oxidase（IOD）and peroxidase（POD）activities in maize seedlings under salt stress were investigated.The results showed,under salt stress,the growth of maize seedlings was promoted by SNP and IAA,IAA content in leaves and root tips of maize seedlings treated with SNP was significantly increased,but IOD and POD activities decreased dramatically.NO production inhibitors Nω-nitro-L-arginine methyl hydrochloride（L-NAME）,NaN3 or NO scavenger 2-（4-carboxyphenyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt（cPTIO）inhibited the increasing effect of SNP on IAA content.These results suggested that NO alleviates the growth inhibition of maize seedling under salt stress by increasing IAA content.NO probably located in the upstream of IAA.