摘 要

杨树是世界上适应性最强，分布最广的树种之一，是我国重要的造林绿化、工业用材树种。本选题以南林895杨为材料，进行盐胁迫研究。通过895杨呼吸及乙烯相关基因表达的监测，胁迫生理指标的测定，探讨895杨呼吸作用对盐胁迫的响应机制，并初步研究线粒体电子传递在乙烯参与抗盐胁迫响应中的调控作用，为杨树抗性分子育种提供理论基础。结果如下：

1. 200 mM和400 mM NaCl盐胁迫分别处理后，杨树叶片表现出受害程度，丙二醛和活性氧含量均与盐浓度呈正相关。
2. 200 mM和400 mM NaCl盐胁迫分别处理后，杨树叶片内乙烯合成相关基因，氰丙氨酸合酶编码基因和交替呼吸氧化酶编码基因均有上调，其中乙烯合成相关基因和氰丙氨酸合酶编码基因均在早期表达增强，然后回落。400 mM NaCl导致交替呼吸氧化酶编码基因早期上升，之后下降；200 mM NaCl则诱导其在较晚的时间点才增强。

关键词：南林895杨；乙烯；氰丙氨酸合酶；交替呼吸氧化酶

Regulation mechanism of ethylene on alternative oxidase in response to salt stress in Populus

ABSTRACT

Poplar is one of the most adaptable and widespread trees in the world, which is an important resource of forestation and wood industry of China. In the present project, Populus x euramericana cv. 'Nanlin895' seedlings was challenged with different concentrations of sodium chloride (NaCl) which is one of the main chemicals forming salt stress. The detection of oxidant stress and measurement of genes involved in ethylene (ETH) biosynthesis and mitochondrial alternative respiration was hired to investigate the regulation mechanisms of mitochondrial alternative respiration in the resistant responses to salt stress in poplar. The present observations not only gave further insight into the regulative role of mitochondrial respiration in the ETH-induced resistant responses to salt stress in poplar, but also were important to provide the resistance breeding and transgenic project with theoretical basis. Results as followed:

1. 200 mM NaCl and 400 mM NaCl treatments caused leaf damages in poplar with malondialdehyde (MDA) increasing and superoxide anion (O₂.^-) generating, which were in positive relation with the NaCl concentration.
2. 200 mM NaCl and 400 mM NaCl treatments induced the expression of genes involved in ETH biosynthesis and cyanoalanine synthase (CAS) encoding at early stage, and then dropped to the control level, compared to water treatment. The alternative oxidase (AOX)-encoding gene AOX1b was up-regulated by both NaCl treatments as well. Therefore, AOX1b was inspired by 400 mM NaCl treatment at early stage and fell back to normal subsequently, while elevated by 200 mM NaCl treatment at lateral stage and no decline was observed.

Key words: Poplar, Ethylene, Cyaninonine synthase, Alternative oxidase

目 录

前言 - 1 -

1文献综述 - 2 -

1.1杨树抗盐机制的研究概况 - 2 -

1.1.1杨树的形态特征及分布 - 2 -

1.1.2杨树的研究价值及生长习性 - 2 -

1.1.3盐胁迫对植物的影响 - 3 -

1.2杨树抗盐机制的研究进展 - 3 -

1.2.1盐胁迫对植物影响的研究方向 - 3 -

1.2.2盐胁迫对植物影响的研究成果 - 3 -

1.3立题依据及意义 - 5 -

2材料与方法 - 6 -

2.1实验材料 - 6 -

2.2实验方法 - 6 -

2.2.1丙二醛（MDA）含量的测定 - 6 -

2.2.2超氧阴离子（O₂.^-）组织化学染色 - 6 -

2.2.3总RNA提取、纯化和cDNA合成 - 6 -

2.2.4 Real-Time PCR分析基因相对表达量 - 7 -

2.2.5 数据分析 - 9 -

3结果与分析 - 10 -

3.1不同浓度盐胁迫对杨树叶片的影响 - 10 -

3.2不同浓度的盐胁迫对杨树叶片氧化胁迫的状况 - 10 -

3.3不同浓度的盐胁迫处理杨树叶片中乙烯合成相关基因表达变化情况 - 11 -

3.4不同浓度的盐胁迫处理杨树叶片中氰丙氨酸合酶基因表达变化情况 - 12 -

3.5不同浓度的盐胁迫处理杨树叶片中交替呼吸氧化酶基因表达变化情况 - 14 -

4结论与展望 - 16 -

4.1结论 - 16 -

4.2本研究的不足之处 - 16 -

4.3展望 - 17 -

致谢 - 18 -

参考文献 - 19 -

前 言

杨树是被子植物门（Angiosperms），双子叶植物纲（Dicots）,杨柳科（Salicaceae）杨属（Populus）的落叶乔木，全属 100 余种，我国有 50 多种。杨树是世界上适应性最强，分布最广的树种之一。杨树是我国重要的造林绿化、工业用材树种。我国西北、华北、东北和沿海地区分布许多盐碱土，而江苏省苏北地处黄海之滨，也拥有大量盐碱土。通常土壤含盐量在0.2%-0.5%时即不利于生长，而盐碱土高达0.6%-10%时，严重伤害植物，危害农林业生产，因此对植物抗盐害的研究十分必要。

南林895杨为美洲黑杨杂种无性系后代，因此具有美洲黑杨的形态特征：高大乔木，主干通直发达，整个生长期为250多天。无性繁殖能力较强，具有相对稳定的遗传特性，喜水、喜肥、喜光，在光照充足、水肥充足的情况下，其生长十分迅速。对溃疡病及褐斑病抗性较强，较耐干旱脊薄，在内陆沿海地区盐碱地上生长良好。