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’杨为材料，进行盐胁迫研究。通过‘895杨’谷氨酸代谢相关基因和氨基酸含量的监测，探讨‘895杨’在不同浓度盐胁迫下氨基酸代谢的差异，对杨树抗盐机理有进一步认识。结果如下：

1. 低浓度盐胁迫下，杨树主要通过GS/GOGAT途径进行谷氨酸合成；高浓度盐胁迫下，杨树则通过GS/GOGAT和GLD两条途径共同进行谷氨酸合成，盐胁迫后期由于胁迫伤害导致两条途径均受到抑制。
2. 低盐浓度胁迫下，杨树ICDH水平偏低，而高盐浓度胁迫下因对α-酮戊二酸需求量提高而强烈诱导ICDH。
3. 不同盐浓度胁迫对于杨树体内氨基酸含量影响不同。缬氨酸及异亮氨酸在低盐胁迫下无显著变化；在高盐胁迫下含量显著增加。低盐胁迫下半胱氨酸无变化，甲硫氨酸增加；高盐胁迫下半胱氨酸减少，甲硫氨酸无显著变化。

关键词：南林‘895杨’；氨基酸代谢；盐胁迫

Amino acid metabolism mechanism of Nalin 895 under different concentration of salt stress

ABSTRACT

Poplar is one of the most adaptable and widely distributed tree species in the world. It is an important tree species for forestation and industrial use in China. In this study, ’Nanlin 895’ was hired to investigate the salt-tolerant mechanisms of woody plant. Monitoring glutamate metabolism-related genes expression and amino acid content in leaves of ‘Nanlin 895’, the variations in amino acid metabolism of ‘Nanlin 895’ under different concentrations of salt stress were discussed, and the mechanism of salt-resistance of poplar was further studied. The results are as follows:

(1) Under low concentration of salt stress, glutamate in poplar leaves was synthesized through the glutamine synthetase/glutamate synthase (GS/GOGAT) pathway. Meanwhile, under high concentration of salt stress, both GS/GOGAT and glutamate dehydrogenase (GLD) pathways were activated to synthesize glutamate. Afterwards, the two pathways were inhibited due to severe stress.

(2)The ICDH level of poplar was low under the stress from low salt concentration, while was strongly induced for the the increased α-ketoglutarate requirement high concentration of salt stress.

(3)Different salt concentration stress led to different effects on the amino acid content of poplar. valine and isoleucine was not significantly changed under low salt stress, but obviously increased under high salt stress, which may be related to ABA anti-salt pathway and NO signal pathway. Lower salt stress resulted in increase of methionine and no changes of cysteine, while higher salt stress led to decrease of cysteine as well as no alternation in methionine content..

Key words: ‘Nanlin 895’; Amino acid metabolism; Salt stress

目 录

前言 1

1文献综述 2

1.1实验研究背景 2

1.1.1杨树的研究价值及生长习性 2

1.1.2盐胁迫对植物的影响 2

2.1目前研究进展 3

3.1实验研究方法 3

4.1本次研究的目的与意义 4

2材料与方法 5

2.1植株和培养条件 5

2.2RNA提取和实时定量PCR 5

2.3游离氨基酸提取与分析 7

3结果与分析 8

3.1不同浓度的盐胁迫处理杨树叶片中谷氨酰胺合酶基因及谷氨酸合酶表达变化情况 8

3.2不同浓度的盐胁迫处理杨树叶片中谷氨酸脱氢酶基因表达变化情况 9

3.3不同浓度的盐胁迫处理杨树叶片中异柠檬酸脱氢酶基因表达变化情况 10

3.4盐处理下杨树叶片中氨基酸的含量 12

4结论与展望 15

4.1结论 15

4.2本研究的不足之处 15

4.3展望 15

致谢 17

参考文献 18

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。