NO对缺氮胁迫下棉花幼苗生理生长的调控效应

【目的】探讨外源一氧化氮（Nitric oxide，NO）对氮素胁迫下棉花幼苗生长和叶片生理性状的影响，为NO的供体硝普钠（Sodium nitroprusside，SNP）调控棉花生长发育提供理论依据。【方法】采用水培处理，设置两个对照：以全营养素Hoagland营养液培养棉花幼苗为对照1（CK1），缺氮Hoagland营养液培养棉花幼苗为对照2（CK2）。在CK2的基础上，利用SNP处理棉花幼苗，设置5个处理，每个处理SNP浓度分别为50、100、200、500和1 000 μmol•L-1，研究NO对氮胁迫下棉花幼苗生理生长的调控效应。【结果】氮素胁迫对棉花幼苗产生抑制作用，导致棉苗的光合系统及蛋白质、脯氨酸含量产生变化。低浓度外源NO能明显促进氮素胁迫下棉花幼苗的生长，显著提高叶绿素、脯氨酸及可溶性蛋白含量，其中以100 μmol•L-1 SNP缓解胁迫效果最好。而高浓度的外源NO则加剧氮素胁迫对棉苗的抑制。【结论】低浓度外源NO（SNP:50—100 μmol•L-1）的确能缓解氮素胁迫对棉花幼苗造成的伤害，提高棉花幼苗对氮素胁迫的耐性。

Regulatory Effects of Exogenous Nitric Oxide on Physiological Growth of Cotton Seedlings Under Nitrogen Stress

【Objective】In order to provide a theoretical basis for regulation of SNP in cotton, the effects of NO donor sodium nitroprusside(SNP) on physiological growth of cotton seedlings were investigated under nitrogen stress. 【Method】 Two control groups were carried out in hydroponic experiment. The first control group cotton seedlings (CK1) were grown with Hoagland''s solution. The second control group cotton seedlings (CK2) were grown with Hoagland''s solution without nitrogen. Five treatment groups were designed under different SNP concentrations using as the basis. The concentrations of SNP, were 50, 100, 200, 500 and 1 000 μmol•L-1, respectively. The growth and leaves physiological characteristics of cotton seedlings under nitrogen stress were measured.【Result】Nitrogen stress inhibited the growth of cotton seedlings. Nitrogen stress changed the photosynthetic system and material content. Low concentration exogenous nitric oxide could increase cotton seedlings growth, increase the content of chlorophyll, proline and soluble protein significantly. The effect of nitrogen stress was relieved by lower concentration of NO (SNP: 100 μmol•L-1). The effect of nitrogen stress was enhanced by high concentration of NO. 【Conclusion】 Lower concentration of NO (SNP: 50-100 μmol•L-1) has a best effect on mitigating cotton seedlings’ nitrogen stress and can increase the tolerance of cotton nitrogen stress.