外源NO对低温胁迫下湿地松幼苗抗性的影响

Effects of Exogenous NO on the Resistance of Pinus elliottii Seedlings to Low Temperature Stress

本试验以湿地松幼苗为试验材料,在人工模拟环境条件下,以硝普钠(SNP)为NO供体,试验研究了外源NO对低温胁迫下湿地松幼苗生长生理的影响。结果表明:与常温(16~25℃)对照处理相比,在低温(4~10℃)处理下,苗木高径生长增量显著下降,叶片叶绿素含量降低,相对电导率、MDA含量、H_(2)O_(2)含量及SOD、POD、CAT活性明显升高。低温下幼苗叶面喷施0~800μmol·L^(-1)SNP,3周后表现为随着SNP浓度增加,叶绿素含量,SOD、POD、CAT活性及可溶性糖、可溶性蛋白、游离脯氨酸含量先上升后下降,相对电导率、MDA含量先下降后上升,而H_(2)O_(2)含量则逐渐增加。利用苗高增量、地径增量、叶绿素含量、相对电导率、丙二醛含量等5个指标作为评价指数和因子分析综合评价法对供试不同浓度NO处理下的幼苗耐低温能力评价结果即SNP浓度(μmol·L^(-1))为:400>800>200>100>0;外源NO对湿地松幼苗耐低温性具有低促高抑作用,最佳使用浓度为400μmol·L^(-1)SNP。

In this experiment,the effect of exogenous NO on the growth and physiology of Pinus elliottii seedlings under low temperature stress were analyzed by using sodium nitroprusside(SNP)as NO donor in the artificial simulated environmental conditions.The results showed that compared with the normal temperature(25℃/16℃)control treatment,the increment of seedling height and diameter growth decreased significantly,the chlorophyll content in leaves decreased,and the relative conductivity,MDA content,H_(2)O_(2)content and SOD,POD,CAT activity increased significantly under low temperature(10℃/4℃)treatment.Seedlings were sprayed with 0~800μmol·L^(-1)SNP under low temperature treatment.After 3 weeks,with the increase of SNP concentration,chlorophyll content,SOD,POD,CAT activity and soluble sugar,soluble protein,free proline content increased first and then decreased,relative conductivity and MDA content decreased first and then increased,while H_(2)O_(2)content increased gradually.The five indexes of seedling height increment,ground diameter increment,chlorophyll content,relative conductivity and malondialdehyde content were used as evaluation indexes.Through factor analysis,the low temperature tolerance of seedlings under different concentrations of NO treatment was:400μmol·L^(-1)SNP>800μmol·L^(-1)SNP>200μmol·L^(-1)SNP>100μmol·L^(-1)SNP>0μmol·L^(-1)SNP.The results showed that exogenous NO had low promotion but high inhibition effects on low temperature tolerance of P.elliottii seedlings,and the optimal concentration was 400μmol·L^(-1)SNP.