尾巨桉DH3229幼苗对硝普钠-酸铝互作的响应

Response of Eucalyptus DH3229 seedlings to SNP-acid aluminum nitrate interactions

关键词:  速生桉, 铝毒害, 一氧化氮, 缓解, 氧化胁迫

Key words:  Eucalyptus, aluminum toxicity, nitric oxide, relieve, oxidative stress

摘要:

该研究以广西林业科学研究院提供的尾巨桉DH3229幼苗为材料,以分析纯AlCl₃·6H₂O为铝(Al)的供体,以硝普钠(SNP)为一氧化氮(NO)的供体,设置3个SNP浓度(0、10、500 μmol·L^-1)和2个Al水平(0、5 mmol·L^-1),每5 d浇一次含不同浓度Al和SNP的营养液,持续20周,分析Al胁迫对幼苗生长生理特性的影响,并探讨不同浓度外源SNP施加对植物Al毒害有无缓解作用及其缓解机理。结果表明:Al施加能显著降低尾巨桉DH3229幼苗的生物量、叶片叶绿素a、总叶绿素含量、叶绿素a/b值和可溶性糖含量; Al胁迫显著增加幼苗相对电导率、MDA、SOD、游离脯氨酸含量。外源施加适量(10 μmol·L^-1)的SNP能使Al胁迫下桉树幼苗根和叶等生物量、叶片叶绿素含量以及Chl a/b显著提高,同时降低其相对电导率、MDA含量和游离脯氨酸含量。可见,SNP具有双重性,适量SNP施加可有效缓解Al对桉树生长的胁迫,高浓度(500 μmol·L^-1)SNP则产生硝化胁迫从而抑制桉树的生长

Abstract:

With Eucalyptus urophylla × E. grandis DH3229 seedlings as test material, a experiment was conducted to study nitric oxide(NO)alleviate the toxic effects of Aluminum(Al). In this experiment, E. urophylla × E. grandis DH3229 were subjected to six treatments [two levels of Al stress and three levels of sodium nitroprusside(SNP)]. In this paper, we measured four plant growth indexs(root biomass, stem biomass, leaf biomass, and root stem ratio)and nine plant physiologic indexs(chlorophyll a, chlorophyll b, chlorophyll a+b, chlorophyll a/b, MDA content, relative electrical conductivity, free proline content, soluble sugar content, and SOD content)among different treatments. We used one-way ANOVAs and Duncan multiple-range test to exam the differences between four plant growth indexs and nine plant physiologic indexs in six treatments. And then, we used principle conponent analysis(PCA)to reduce the number of dimensions without much loss of information based on similarities and differences, and we defined a limited number of “principal components” that describe independent variation structures in the data. At last, we chose an appropriate SNP content to alleviate the toxic effects of Al. The results showed that Al stress significantly inhibited root, stem, leaf biomass of seedlings, and the content of leaf chlorophyll a, chlorophyll a+b. Meanwhile, Al stress significantly increased the relative electrical conductivity, MDA, SOD and proline content. The application of 10 μmol·L^-1 SNP increased siginificantly root and leaf biomass, the content of chlorophyll a and chlorophyll b, chlorophyll a/b under Al stress; and decreased siginificantly the relative electrical conductivity, MDA and proline content. Apply an appropriate amount of SNP could effectively alleviate the toxic effects of Al on Eucalyptus seedling growth. However, high concentration of SNP could inhibit the growth of Eucalyptus seedling.