外源NO对NaCl胁迫下棉苗主要形态和相关生理性状的影响

Effects of Exogenous Nitric Oxide on Main Growth and Physiological Characteristics of Seedlings of Cotton Under NaCl Stress

【目的】研究不同浓度外源NO供体硝普钠(SNP)对不同NaCl胁迫程度下棉苗生长和叶片生理性状的影响。【方法】采用水培处理,试验设2个NaCl水平(50和100 mmol.L-1),各NaCl水平下设4个SNP浓度(0、50、100和200μmol.L-1),同时设对照(0 mmol.L-1NaCl,0μmol.L-1SNP),处理10 d后测定棉苗形态指标和叶片主要生理指标。【结果】NaCl胁迫抑制棉苗生长;外源NO供体SNP进一步抑制NaCl胁迫下棉苗节间伸长,显著降低植株含水量,尤其是根和茎的含水量;SNP处理显著增加轻度盐胁迫(50 mmol.L-1NaCl)下棉苗比叶重,50—200μmol.L-1SNP处理下比叶重增加10%—18%;SNP处理提高了高盐(100 mmol.L-1NaCl)胁迫下棉苗叶片可溶性蛋白含量和叶绿素a/b值,显著提高了叶绿素a、b含量,以50μmol.L-1SNP处理效果最显著,叶绿素a、b分别增加10.9%和9.8%;SNP显著提高了NaCl胁迫下叶片SOD活性和POD活性,降低了CAT活性。【结论】外源NO能够抑制棉苗节间伸长,缓解高浓度NaCl胁迫下棉苗叶绿素的降解,增强叶片抗氧化能力,改善叶质。本试验条件下,SNP对棉苗盐胁迫的缓解作用以50—100μmol.L-1为宜,高浓度(200μmol.L-1)SNP处理加剧了盐胁迫对棉苗的伤害。

[ Objective] The purpose of this study is to clarify the effects of nitric oxide （NO） on cotton seedlings growth and leaf physiological characteristics under NaCI stress. [Method] In a hydroponic experiment, two NaC1 concentrations （50 mmol·L^-1 and 100mmol·L^-1）, four sodium nitroprusside （SNP） concentrations （0, 50, 100 and 200 umol·L^-1） for each NaC1 level were designed, and at the same time a conventional culture was set. The growth and leaves physiological characteristics of cotton seedlings were measured after 10 days of treatment. [ Result ] The results showed that the treatment of NaCI stress inhibited the growth of cotton seedlings. The internodes of the cotton seedlings under NaC1 stress were inhibited further by SNP which is an exogenous nitric oxide donor. The relative water content of cotton seedlings, especially the relative water content of the stem and root were decreased in SNP treatments under NaCI stress. The treatments of SNP added in 100 rnmol-LI NaC1 stress increased the contents of soluble protein and chlorophyll, and the ratio of chlorophyll a/b, the effects of 50 pmol-L~ SNP was the best. Under both of the NaC1 stresses, SNP improved the activities of SOD and POD significantly, while the activities of CAT decreased. [Conclusion] Under this experimental condition, exogenous nitric oxide inhibited internodes elongated, alleviated chlorophyll degradation, enhanced antioxidant capacity and improved leaves quality of cotton seedlings under NaCI stress. The SNP concentration from 50mmol·L^-1 to 100mmol·L^-1 could alleviate NaCl stress for cotton seedlings, the cotton seedlings under NaCI stress were seriously injured by high concentrations （200umol·L^-1 ） of SNP.