外源硒和硅对镉胁迫下苎麻生理响应的影响研究

发布时间：2018-04-08 18:46

本文选题：镉污染　切入点：苎麻　出处：《湖南大学》2015年硕士论文

【摘要】：作为一种具有生物毒性的重金属,镉(Cadmium,Cd)对动植物甚至人体健康都有很大的危害。本实验以湖南省本土植物苎麻(Boehmeria nivea(L.)Gaud.)为研究材料,通过水培实验,研究了Cd对苎麻生理生长的影响和在苎麻体内的分布情况,以及外源物质硒(Selenium)和硅(Silicon)对Cd胁迫下苎麻所受毒害的缓解效应和机制研究,主要分析了Cd污染下苎麻的生长、苎麻对Cd的吸收和转运、苎麻光合作用以及抗氧化系统,探索了Se和Si对增强苎麻对Cd耐受性的机理,为提高苎麻修复重金属污染能力提供参考依据。本研究得出的主要结论如下:1、苎麻是一种耐Cd植物,具有一定的Cd富集能力。苎麻体内Cd含量大小表现为根茎叶,重金属主要富集在根部,部分转移到地上部分的茎叶组织,有效减轻了地上部分受到的重金属毒害。但是,Cd能对苎麻的正常生长和代谢造成损伤。具体表现为生长受到抑制导致根系和地上部分的生长量降低,MDA含量升高,蛋白质和叶绿素含量下降以及脯氨酸含量增加,这可能是苎麻在胁迫环境下的一种适应性调节作用。2、Cd胁迫下,施加低浓度Se(0.5,1.0,1.5μM)能适当缓解苎麻受到的毒害作用,缓解Cd造成的生长抑制、降低苎麻对Cd的吸收,体现出拮抗作用;而高浓度Se(2,5,10μM)则加重Cd对苎麻的毒害,增强苎麻对Cd的富集能力,体现为协同作用,表明高浓度硒对植物能产生毒害。3、Cd胁迫下,外源物质Se和Si对苎麻生长有促进作用,能促进苎麻的生长量和叶绿素含量,并抑制苎麻对Cd的吸收量以及向地上茎叶组织的转运效率TF,降低MDA和H_2O_2含量,充分表明Se和Si均能缓解Cd胁迫对苎麻造成的过氧化损伤。4、Se和Si主要通过以下方式解苎麻体内的氧化损伤作用:其一是提高植物体内抗氧化酶(如SOD、POD等)的活性,加快对体内过量自由基的清除效率;其二是刺激抗坏血酸-谷胱甘肽循环的高效运行,苎麻通过加速该循环清除活性氧,使植株避免氧化伤害;此外,维生素E与抗坏血酸-谷胱甘肽循环相互配合,共同作用,这也许是苎麻对Cd污染引起的氧化胁迫的一种重要的忍耐与解毒机制。而且两者的联用对苎麻产生的积极效果更佳。
[Abstract]:As a biotoxic heavy metal, cadmium (Cadmium) is harmful to animals and plants and even to human health.In this study, the native plant Boehmeria nivea L.Gaud. of Hunan Province was studied.In order to study the effects of CD on the physiological growth of Ramie and its distribution in Ramie, the effects and mechanisms of exogenous selenium (selenium) and Silicon (Silicon) on the toxicity of Ramie (Ramie) under CD stress were studied by hydroponic experiments.The growth of Ramie under CD pollution, the absorption and transport of CD, photosynthesis and antioxidant system of Ramie were analyzed. The mechanism of se and Si to enhance the tolerance of Ramie to CD was explored.In order to improve Ramie remediation heavy metal pollution ability to provide the reference basis.The main conclusions of this study are as follows: 1. Ramie is a CD tolerant plant with CD enrichment ability.The content of CD in Ramie was shown as rhizome and leaf. Heavy metals were mainly concentrated in the roots and transferred to the stems and leaves of the aboveground parts, which effectively alleviated the toxicity of heavy metals to the aboveground parts.But CD can damage the normal growth and metabolism of Ramie.The results showed that the growth of roots and aboveground parts decreased, the content of MDA increased, the content of protein and chlorophyll decreased, and the content of proline increased.This may be a kind of adaptive regulation effect of Ramie under stress environment. Under the stress of CD, the application of low concentration of se _ (0.5) O _ (1.0) ~ (1.5 渭 M) can properly alleviate the toxic effect of Ramie, alleviate the growth inhibition caused by CD, reduce the absorption of CD by Ramie, and reflect the antagonistic effect.However, the high concentration of se _ (2) O _ (5) (10 渭 M) increased the toxicity of CD to Ramie and enhanced the ability of CD enrichment in Ramie, which indicated that the exogenous substances se and Si could promote the growth of Ramie under the stress of high concentration of se _ (2) O _ (2) O _ (5) C _ (2) and CD _ (3).It could promote the growth and chlorophyll content of Ramie, inhibit the uptake of CD and transport efficiency to stem and leaf tissue of Ramie, and decrease the contents of MDA and H_2O_2.The results showed that se and Si could alleviate the oxidative damage of Ramie caused by CD stress. 4Se and Si could improve the activity of antioxidant enzymes (such as SOD POD) in Ramie.The second is to stimulate the efficient operation of ascorbic acid-glutathione cycle, by accelerating the removal of reactive oxygen species in Ramie plants to avoid oxidative damage; in addition,Vitamin E and ascorbic acid-glutathione cycle cooperate with each other, which may be an important tolerance and detoxification mechanism of Ramie to oxidative stress caused by CD pollution.And the combination of the two to Ramie produced a better positive effect.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X173;X171.5

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