富氢水（HRW）对汞诱导的紫花苜蓿幼苗根部氧化伤害的缓解作用

发布时间：2018-03-03 03:07

本文选题：富氢水　切入点：紫花苜蓿　出处：《南京农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：汞(Hg)是环境中有毒重金属污染的主要来源之一,对植物细胞有很强的毒害作用。高等植物很容易积累汞,汞积累能够诱导活性氧的爆发,造成植物氧化胁迫伤害。最近研究表明氢气(H2)是一种新的生物调节分子,参与植物的一系列生理活动。然而,我们还不清楚氢气是否能够调节植物对汞毒害的适应能力。本文用富氢水(HRW)预处理研究了其对汞诱导的紫花苜蓿幼苗根部氧化伤害的缓解作用,阐述了氢气在缓解汞毒害中的生理作用和相关的分子机理。研究结果表明:1.氯化汞(HgCl2)处理紫花苜蓿幼苗能诱导植物强烈的氧化伤害。不同浓度的HgCl2(1、10、100和500μM)处理,紫花苜蓿幼苗根部中TBARS含量呈现浓度依赖性;10 μMHgCl2处理与对照组相比TBARS含量增加了 91.6%,可以作为最适胁迫浓度;进一步研究发现,不同浓度的HRW(1、10、50和100%)预处理能降低汞诱导的TBARS,其中,10%HRW预处理TBARS降低最显著,可以作为后续研究最适的浓度。2.10%HRW预处理能够缓解汞毒害引起的一些症状,包括改善幼苗的生长、缓解幼苗根部的生长抑制和提高幼苗的干重和鲜重。进一步研究发现,10%HRW预处理后,紫花苜蓿幼苗根部汞的积累明显下降。组织学染色的结果表明,与对照相比,汞处理诱导大量ROS的产生,10%HRW预处理能够缓解汞诱导的氧化伤害。3.汞诱导的超氧化物歧化酶(SOD)活性以及其同工酶活性的增加能够显著的被10%HRW逆转。进一步的研究表明,10%HRW能够在酶水平和转录水平上提高两种过氧化氢清除酶一愈创木酚过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)的活性和转录本。同时,还原型与氧化型谷胱甘肽(GSH)比值、同源型谷胱甘肽(hGSH)含量、抗坏血酸(AsA)含量以及相关基因表达也呈现显著增加的趋势,上述与HRW缓解紫花苜蓿幼苗根部氧化性损伤的结果是一致的。总之,上述研究结果表明,HRW能缓解汞胁迫引起毒害,上述效应可能与缓解紫花苜蓿幼苗根部生长的抑制以及汞的积累,延缓氧化胁迫和重建氧化还原稳态等有关。
[Abstract]:HG) is one of the main sources of toxic heavy metal pollution in the environment, and has a strong toxic effect on plant cells. Higher plants can easily accumulate mercury, mercury accumulation can induce the outbreak of reactive oxygen species. Recent studies have shown that H _ 2H _ 2) is a new biological regulatory molecule involved in a series of physiological activities in plants. It is not clear whether hydrogen can regulate the adaptability of plants to mercury toxicity. In this paper, the effects of hydrogen on oxidative damage induced by mercury in alfalfa seedlings were studied by hydrogen rich water (HRW) pretreatment. The physiological function and molecular mechanism of hydrogen in mitigating mercury toxicity were described. The results showed that the treatment of HgCl2) could induce strong oxidative damage in alfalfa seedlings. Different concentrations of HgCl2HgCl2 (100 渭 M and 500 渭 M) could induce oxidative damage in alfalfa seedlings. The concentration of TBARS in the roots of alfalfa seedlings showed a concentration dependence of 10 渭 MHgCl2. Compared with the control group, the content of TBARS increased by 91.6 渭 MHgCl2, which could be regarded as the optimal stress concentration. Pretreatment with different concentrations of HRW can reduce the mercury induced TBA, and the TBARS of 10 HRW pretreatment is the most significant, which can be used as the best concentration in the follow-up study to alleviate some symptoms caused by mercury toxicity, including improving seedling growth. It was found that the accumulation of mercury in the roots of alfalfa seedlings decreased significantly after pretreatment with 10 HRW. The results of histological staining showed that the results of histological staining showed that the content of mercury in the roots of alfalfa seedlings was significantly lower than that of the control. Mercury treatment induced a large number of ROS production. The pretreatment of 10 HRW alleviated the oxidative injury induced by mercury. The increase of mercury-induced superoxide dismutase (SOD) activity and its isozyme activity could be significantly reversed by 10HRW. The further study shows that the increase of mercury-induced superoxide dismutase (SOD) activity can be reversed by 10HRW. The HRW can increase the activity and transcripts of two hydrogen peroxide scavenger enzymes, guaiacol peroxidase (POD) and ascorbic acid peroxidase (APX), at both the enzyme level and the transcriptional level. The ratio of reductive to oxidized glutathione (GSH), homologous glutathione hGSH, ascorbic acid ascorbic acid (ascorbic acid) and related gene expression also increased significantly. These results are consistent with the results of HRW in alleviating oxidative damage in alfalfa seedlings. These effects may be related to alleviating the inhibition of root growth and accumulation of mercury, delaying oxidative stress and reconstructing redox homeostasis of alfalfa seedlings.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X171.5;S541.9

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