一氧化氮参与调节盐胁迫诱导的玉米幼苗脱落酸积累

Involvement of Nitric Oxide in Regulation of Salt Stress-induced ABA Accumulation in Maize Seedling

以三叶一心期的玉米幼苗为实验材料,研究了盐胁迫下玉米幼苗根尖和叶片中一氧化氮(NO)和脱落酸(ABA)积累之间的关系。结果表明,盐胁迫下玉米幼苗NO和ABA的含量均增加,用NO供体硝普钠(sodiumnitroprusside,SNP)处理时,ABA含量亦增加,且累积的时间较盐胁迫下早。用NO合成的抑制剂L-NAME(Nω-nitro-L-argininemethylesterhydrochloride)和NaN3处理时,可减弱盐胁迫诱导的ABA含量的增加,用NO清除剂cPTIO处理时,这种盐胁迫诱导的ABA增加减少。推测盐胁迫下产生的NO参与调节ABA的积累及逆境下植物的防御反应。

Possible regulation of salt stress-induced ABA accumulation by nitric oxide （NO） in maize seedling was investigated. Both NO and ABA contents of maize leaves and root tips were increased in response to salt stress （Figs. 1, 2）. Similar to the effects of salt stress, ABA contents of maize leaves and root tips were increased after the treatment of maize leaves with sodium nitroprusside （SNP, a nitric oxide donor） alone （Fig.3）. Compared to the salt stress-induced ABA accumulation, this SNP-induced ABA increase was much faster, suggesting that NO may be an intermediate signal from salt stress to ABA accumulation. When NO production inhibitors L-NAME and NaN3 treatments were applied, salt stress-induced ABA accumulation was lowered （Fig.4）. Treatment with NO scavenger cPTIO also inhibited the salt stress-induced ABA increase （Fig. 5）. From these results it is deduced that NO is involved in regulation of ABA accumulation under salt stress.