柳枝稷对镉胁迫的响应及其作为镉污染土壤修复植物的潜力研究

发布时间：2018-03-11 18:09

本文选题：柳枝稷　切入点：镉　出处：《西北农林科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着我国工业的不断发展,重金属污染土壤的环境问题也日益严峻,对环境、人类健康和食品安全造成了巨大的安全隐患。而传统重金属污染土壤的治理方法耗时耗资,有很多局限性,因此,研究开发高效、环保、经济的新型重金属污染土壤治理方法势在必行。植物修复技术具有环保、低成本等特点,一经提出就受到人们广泛关注,而且被认为是一种最具潜力的重金属污染土壤修复技术,因此选择适当的超积累植物或者对重金属有较强耐受性植物是十分必要的,同时了解不同植物所适宜的土壤环境条件也是该修复技术能否成功的关键。本研究通过(1)单因素镉胁迫下种子萌发实验、(2)三因素(镉、pH和浸种时间)五水平正交旋转设计种子萌发实验和(3)二因素(镉和pH)五水平正交旋转设计共3个实验,探究因素重金属镉和pH单独及交互作用对柳枝稷种子萌发、幼苗发育以及植株地上部分对镉的富集能力等方面的影响。同时,比较不同品种柳枝稷对镉耐受性的差异并对柳枝稷地上部分镉富集能力进行模型分析,通过模型分析,在水培模拟柳枝稷在镉污染土壤条件下,对柳枝稷种子萌发和幼苗生长等表现进行了综合分析和系统评价。研究结果表明:1.柳枝稷种子对镉较不敏感,具有较好的镉耐受性,同时pH和浸种并不影响两个柳枝稷种子发芽率,但是浸种可以提高两个柳枝稷品种的发芽指数。两种柳枝稷品种均对低浓度的镉有一定耐受性,且K品种幼苗与B品种相比表现出较弱的镉抗性。播种前适当浸种可以提高柳枝稷种子和幼苗的活力,从而增强其对重金属镉的耐受性。中性和较强酸性条件下均不适宜柳枝稷生长,而适度弱酸性条件有利于柳枝稷幼苗的生长发育。幼苗前期生长发育对其后期的在镉胁迫环境下生长及成株对镉的吸收富集有重要影响,因此在镉胁迫条件下,柳枝稷种子较适宜播种在偏酸性条件下来进行植物修复作用。2.柳枝稷是一种很有潜力的对重金属镉污染土壤修复植物,同时柳枝稷也是看作是对镉耐性机理研究和毒物刺激效应原理研究的新型模式植物。保证柳枝稷正常生长的前提下又能最大化的利用其对镉富集作用的外界环境镉和pH值范围分别为:50-175μmol/L和4.1-5.9,并且在利用植物修复技术治理重金属污染土壤时也应该将重金属对植物的刺激促进作用加以考虑。3.不同品种柳枝稷对镉的耐受性以及对镉的富集能力有较大差异,同时环境的pH值也显著影响植物对镉的吸收能力,因此想要利用植物修复技术治理重金属污染土壤需要综合考虑环境条件,选择恰当合适的修复植物。然而关于柳枝稷对镉耐受性的生理学和分子生物学机理仍有待于将来进一步深入研究。
[Abstract]:With the continuous development of industry in China, the environmental problems of heavy metal contaminated soil are becoming more and more serious, which has caused a huge safety hazard to the environment, human health and food safety. However, the traditional treatment methods of heavy metal contaminated soil are time-consuming and expensive. There are many limitations, therefore, it is imperative to research and develop a new treatment method of heavy metal contaminated soil with high efficiency, environmental protection and economy. Plant remediation technology has the characteristics of environmental protection, low cost and so on. And is considered to be one of the most promising remediation techniques for heavy metal contaminated soils, so it is necessary to select suitable superaccumulative plants or plants with strong tolerance to heavy metals. At the same time, understanding the suitable soil environmental conditions of different plants is also the key to the success of the remediation technique. The experiment of seed germination under single factor cadmium stress was carried out in this study. Five levels orthogonal of three factors (cadmium pH and seed soaking time). Two factors (cadmium and pH) were designed for seed germination and three experiments were carried out. To explore the effects of cadmium and pH on seed germination, seedling development and the accumulation ability of cadmium in the aboveground part of the plant. The differences of cadmium tolerance of different varieties of switchgrass were compared, and the accumulation ability of cadmium in aboveground part of switchgrass was analyzed by model analysis. The seed germination and seedling growth of switchgrass were comprehensively analyzed and systematically evaluated. The results showed that the seed of switchgrass was less sensitive to cadmium and had better tolerance to cadmium. At the same time, pH and seed soaking did not affect the germination rate of two varieties of switchgrass, but soaking could increase the germination index of two varieties of switchgrass. Both varieties of switchgrass had some tolerance to low concentration of cadmium. K variety seedlings showed weaker cadmium resistance than B varieties and soaking seeds before sowing could improve the vigor of switchgrass seeds and seedlings. In order to enhance its tolerance to heavy metal cadmium, both neutral and strong acidic conditions are not suitable for the growth of switchgrass, The condition of moderate weak acidity is beneficial to the growth and development of switchgrass seedlings. The early growth and development of the seedlings have an important effect on the growth of the seedlings in the later stage of cadmium stress and the absorption and enrichment of cadmium by adult plants, therefore, under the condition of cadmium stress, The seeds of switchgrass are suitable for plant remediation under the condition of partial acid. 2. Switchgrass is a potential remediation plant for heavy metal cadmium contaminated soil. At the same time, switchgrass is also regarded as a new model plant to study the mechanism of cadmium tolerance and the principle of toxic stimulation effect. It can maximize the use of cadmium enrichment in the external environment while ensuring the normal growth of switchgrass. The range of cadmium and pH values are respectively in the range of: 50-175 渭 mol/L and 4.1-5.9 渭 mol/L, respectively. The stimulative effects of heavy metals on plants should also be taken into account when using phytoremediation techniques to treat soils contaminated by heavy metals. The tolerance of different varieties of switchgrass to cadmium and. There is great difference in the enrichment ability of cadmium. At the same time, the pH value of the environment also has a significant effect on the absorption capacity of cadmium by plants. Therefore, if we want to use phytoremediation technology to treat heavy metal contaminated soil, we should consider the environmental conditions comprehensively. However, the physiological and molecular mechanisms of cadmium tolerance of switchgrass still need to be further studied in the future.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S578;X53;X173

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