不同栾树品种对镉胁迫的生理响应及富镉差异研究

发布时间：2018-05-12 08:07

  本文选题：栾树 + 镉胁迫　； 参考：《中南林业科技大学》2017年硕士论文

【摘要】：土壤重金属污染影响食品安全,危及人类健康。栾树具有富集重金属的特性,且生长迅速、生物量大、适应性强,是矿山废弃地修复的首选树种。然而,不同栾树品种间富镉生理机制和富镉差异至今仍未见报道。本研究采用盆栽试验,研究了镉胁迫对复羽叶栾树、黄山栾树和北京栾树植株株高、叶绿素含量、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性、可溶性蛋白含量和游离脯氨酸含量的影响,以及3个栾树品种植株叶和根富镉差异,其目的是筛选出富镉性较强的栾树品种并阐明其富镉生理机制,为栾树应用于镉污染土壤修复提供理论依据。主要研究结果如下:(1)随着土壤中外源添加镉浓度的增加,3种栾树植株株高的增量呈逐渐降低的趋势。除镉浓度为50mg.kg-1处理外,其余各处理植株株高与CK相比影响显著。(2)随着土壤外源添加镉浓度的增加,3个品种栾树植株叶绿素含量呈现上升后下降的趋势,三个品种叶绿素含量的大小为:复羽叶栾树黄山栾树北京栾树。各处理叶绿素含量与CK相比差异显著,各但品种之间叶绿素含量差异不显著。在镉浓度为400mg.kg-1时,3个品种栾树幼苗叶绿素含量低于对照组。(3)不同镉浓度胁迫下,三个品种栾树植株叶和根中SOD、POD、CAT活性随着镉浓度的增加呈现先升高后降低的趋势,叶中酶活性高于根,且叶和根SOD、POD、CAT活性达峰值时所受的镉胁迫浓度不同。各项酶活与CK相比差异显著或极显著。(4)不同镉浓度胁迫下,三个品种栾树植株叶和根中可溶性蛋白的含量随着镉浓度的增加呈现先上升后下降的趋势,且叶中可溶性蛋白含量高于根;叶中游离脯氨酸的含量随着镉浓度的增加呈现逐渐上升,而根中脯氨酸含量在镉浓度为400mg.kg-1时,呈现下降的趋势。(5)不同镉浓度胁迫下,栾树植株根系对镉的富集大于叶片,各处理和各品种间镉含量差异极显著,可以认为根系是栾树富集镉的主要部位。结果表明栾树富镉的生理机制为根吸收土壤中的镉并转运到叶中,抗氧化酶活性的升高及可溶性蛋白含量及游离脯氨酸含量的增加,提升了对镉胁迫逆境的抵抗能力。综合比较得出复羽叶栾树耐镉性较强,可以作为镉污染土壤修复树种。
[Abstract]:Heavy metal pollution in soil affects food safety and endangers human health. Luan tree has the characteristics of enrichment of heavy metals, rapid growth, large biomass, strong adaptability, and is the first choice of tree species for the restoration of mine wasteland. However, the physiological mechanism of cadmium enrichment and the difference of cadmium enrichment among different Luan tree varieties have not been reported. Pot experiment was conducted to study the effects of cadmium stress on plant height, chlorophyll content, superoxide dismutase (SOD) activity, peroxidase (POD) activity and catalase (CAT) activity in the leaves of Luan, Huangshan Luan and Beijing Luan. The effects of soluble protein content and free proline content, and the difference of cadmium enrichment in leaves and roots of three Luan tree varieties, were studied in order to screen the varieties with strong cadmium enrichment and elucidate the physiological mechanism of cadmium enrichment. It provides a theoretical basis for the application of Luan tree to the remediation of cadmium contaminated soil. The main results were as follows: (1) the increment of plant height of three kinds of Luan tree showed a decreasing trend with the increase of exogenous cadmium concentration in soil. Except for the 50mg.kg-1 treatment, the plant height of the other treatments had a significant effect on the plant height compared with CK.) with the increase of exogenous cadmium concentration in soil, the chlorophyll content of the three varieties Luan Shu plants increased and then decreased. The chlorophyll content of the three varieties is: Luanchuan Luan, Huangshan Luan, Luan, Beijing Luan. There was significant difference in chlorophyll content between treatments and CK, but there was no significant difference among varieties. When cadmium concentration was 400mg.kg-1, the chlorophyll content of three varieties Luan tree seedlings was lower than that of the control group. (3) under different cadmium concentration stress, the activities of POD cat in leaves and roots of three varieties Luan tree increased first and then decreased with the increase of cadmium concentration. The activity of enzyme in leaves was higher than that in roots, and the concentration of cadmium stress was different when the activity of POD cat in leaves and roots reached the peak. The content of soluble protein in leaves and roots of three varieties of Luan tree increased firstly and then decreased with the increase of CD concentration. The soluble protein content in leaves was higher than that in roots, and the content of free proline in leaves gradually increased with the increase of cadmium concentration, while the content of proline in roots showed a decreasing trend when cadmium concentration was 400mg.kg-1. The concentration of cadmium in roots of Luan tree was higher than that in leaves, and there were significant differences among different treatments and varieties. It can be concluded that root system is the main part of cadmium enrichment in Luan tree. The results showed that the physiological mechanism of cadmium rich in Luan Shu was that the root absorbed cadmium from soil and transported it to the leaves. The increase of antioxidant enzyme activity and the increase of soluble protein content and free proline content increased the resistance to cadmium stress. The comprehensive comparison showed that the compound leaf Luan tree had stronger tolerance to cadmium and could be used as a remediation tree for cadmium contaminated soil.
【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53;X173;S792.99
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本文编号：1877824