外源NO对棉花幼苗重度镉胁迫的缓解效应

为探讨外源一氧化氮(NO)对棉花幼苗重度镉(Cd)胁迫的缓解效应,以农大棉601号为试验材料,采用水培方法,研究了不同浓度(50、100、200μmol/L)硝普钠(SNP,NO供体)对重度Cd胁迫(75μmol/L)下棉花幼苗生长的影响。结果表明,Cd处理下棉苗株高、叶面积较CK(不添加CdCl_2和SNP)显著下降40.9%、31.9%,干物质积累量、组织含水量仅为CK的34.3%、33.2%,光合速率显著下降。重度Cd胁迫下添加低浓度外源NO(50、100μmol/L),棉花幼苗株高、叶面积较T0处理(75μmol/L CdCl_2)稍有增加(P0.05),叶绿素含量比T0处理(75μmol/L CdCl_2)分别增加4.5%、15.5%(P0.05),光合速率分别增加36.6%、27.9%(P0.05),其他指标均无显著增加;而添加高浓度NO(200μmol/L)下棉苗干物质积累量、根冠比、组织含水量、叶绿素含量均低于T0处理。因此认为,外源NO对重度Cd胁迫下棉苗生长的缓解效果不显著。

Mitigative Effects of Exogenous NO on Cotton Seedlings under Severe Cd Stress

To investigate the relieving effects of exogenous nitric oxide (NO) on cotton seedlings under severe Cd stress,Nongdamian No.601 was used as test material to study the effects of different concentrations (50,100,200 μmol/L) of sodium nitroprusside (SNP,the donor of NO) on cotton seedlings under severe Cd stress(75 μmol/L)using hydroponics method.The results showed that under severe Cd stress,the plant height and leaf area of cotton seedling were significantly decreased by 40.9％ and 31.9％ compared with CK(without CdCl2 and SNP);dry matter accumulation and tissue water content were only 34.3％ and 33.2％ of CK;photosynthetic rates declined significantly.Under severe Cd stress,compared with T0 treatment (75 μmol/L CdCl2),for the treatments with 50 and 100 μmol/L NO,the plant height and leaves area increased slightly(P ＞ 0.05),chlorophyll contents increased by 4.5％ and 15.5％ respectively (P ＞ 0.05),photosynthetic rate increased by 36.6％ and 27.9％ (P ＞ 0.05),and other indexes did not change significantly;however,for the treatments with 200 μmol/L NO,the dry matter accumulation,root/shoot ratio,tissue water content,and chlorophyll content decreased.Therefore,the relieving effects of exogenous NO on the growth of cotton seedlings under severe Cd stress were not significant.