盐胁迫下NO对玉米幼苗生理特性的影响

Enhancement of exogenous nitric oxide to maize seedlings' resistance to salt stress

为探讨外源一氧化氮（NO）供体和清除剂对玉米幼苗抗盐性的影响,用50 mmol/L的NaCl浇灌4叶期的玉米幼苗造成盐害,同时加入10~100μmol/L的NO生成剂硝普钠（SNP）或清除剂CPTIO。试验结果表明,加入NO供体SNP可以提高玉米叶片中NO的含量,降低超氧阴离子的产生速率,降低叶片脂氧合酶活性（LOX）、丙二醛（MDA）含量和相对电导率,提高叶片相对含水量、延缓叶绿素的降解和提高植株干重;在SNP不同的使用浓度中,以40μmol/L的SNP效果最好,当SNP浓度过低和过高时均达不到理想的效果。当NO被CPTIO清除后则加速玉米的受害程度。因此适当浓度NO能够减轻玉米受盐胁迫的伤害。

To investigate whether maize（Zea mays L. ）seedlings＇ tolerance to salt stress could be enhanced by exogenous nitric oxide, stress was made to maize seedlings at 4 - leaf stage with 50 mmol/L of NaCl, and meanwhile various content of NO donor sodium nitroprusside（SNP） and NO scavenger CPTIO （2 - （4 - Car- boxyphenyl） - 4, 4, 5, 5 - tetramethylimidazoline - 1 - oxyl - 3 - oxide potassium salt） were added. The resuits showed that,with its concentration at 10-100 μmol/L SNP, the NO donor, could increase significantly the content of nitric oxide （NO）, chlorophyll and relative water content in leaves, but decreased the super oxid- tase redicals generating rate and LOX activities of leaves, meanwhile the content of malondiadehyde （MDA） and relative conductance were reduced but the dry weight of maize seedling was increased, and 40μmol/L SNP had the most satisfactory effectt, while higher or lower SNP content had no such satisfactory effect. The stress to the growth of maize was accelerated when NO was eliminated by NO scavenger （CPTIO）. So it could be coneluded that proper content of NO could enhance maize seedlings＇ resistance to salt stress. While the effect was distinctly different when treated with 10--100 μmol/L NO scavenger CPTIO. These results suggested that the propriety NO content can enhance maize seedlings＇ resistance to salt stress.