绿萝（Epipremnum aureum）对重金属的富集特性及相关机制的研究

发布时间：2018-03-16 04:25

本文选题：绿萝　切入点：铅　出处：《中国海洋大学》2015年硕士论文　论文类型：学位论文

【摘要】：近几年来,由于重金属污染日益严重,探索更有效、更环保的措施治理重金属污染是势在必行的,而植物修复技术正在这个领域逐渐崭露头角,以其环保、低成本的特性逐渐成为治污领域的热门。绿萝作为优良的观叶植物,可以用于园林、景观绿化等,但目前关于绿萝对重金属耐受性方面的研究鲜见报道。本研究以绿萝为材料,利用水培法初步探究了绿萝在低、高浓度的铅(Pb)镉(Cd)24h和20d胁迫下的响应特征,以了解绿萝对重金属铅和镉的耐受性、富集作用和相关理化特征；为绿萝用于受重金属铅、镉污染土壤及水体的恢复提供理论和实践依据。本研究的主要结果如下：(1)绿萝在含有不同浓度pb2+、Cd2+的培养液中短期胁迫24小时后,研究表明随着pb2+、Cd2+处理浓度的增加,绿萝根部富集铅、镉的含量也随之增加；低浓度的pb2+对根尖的伸长有促进作用,高浓度有抑制作用；而Cd2+无论低浓度还是高浓度均对根部伸长有显著的抑制作用；根中MDA含量均随着pb2+、Cd2+胁迫浓度的提高而增加。同时,随着铅、镉处理浓度的提高,根部超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)活性均呈逐渐增大的趋势。结果表明绿萝根部通过提高SOD、CAT、POD活性来保护其膜质过氧化损伤。(2)外源添加钙处理在高浓度pb2+、高浓度Cd2+ 24h胁迫下的绿萝,与未加钙的铅、镉胁迫组相比,根部富集铅、镉的含量明显低于未加钙的铅、镉胁迫组；根部伸长量明显高于未加钙的铅、镉胁迫组；MDA含量、SOD、CAT、POD活性均低于未加钙的铅、镉胁迫组。结果表明外源添加钙对高浓度pb2+、高浓度Cd2+所导致的毒性效应有缓解作用。(3)将绿萝培养在含有不同浓度pb2+、Cd2+的培养液中20天后,均表现为根部积累的铅、镉含量最多,茎次之,叶最低,其中根中积累的铅、镉含量与茎、叶中差异显著。同时,在对绿萝根、茎、叶中金属硫蛋白(MT)含量的分析中,发现在pb2+、Cd2+胁迫下根中MT含量最高,叶中次之,茎中最低；并且随着铅、镉处理浓度的升高,根、茎、叶中MT含量均呈现先迅速上升后下降再缓慢上升的趋势。结果表明植物体内的铅、镉诱导了植物体内MT的合成,用于络合金属离子,缓解高浓度pb2+、Cd2+所导致的毒害效应。在对叶片叶绿素含量的分析中,发现随着铅、镉处理浓度的提高,叶绿素含量均呈现先上升后下降的趋势。
[Abstract]:In recent years, because heavy metal pollution is becoming increasingly serious, it is imperative to explore more effective and more environmentally friendly measures to control heavy metal pollution, and plant restoration technology is gradually emerging in this field to protect the environment. The characteristic of low cost has gradually become a hot spot in the field of pollution control. As an excellent foliage plant, green apple can be used in gardens and landscape greening, but there are few reports on the tolerance of green apple to heavy metals. In order to understand the tolerance, enrichment and physical and chemical characteristics of heavy metal lead and cadmium, the response characteristics of green apple under low and high concentration of lead (Pb) CD (CD) and CD (CD) for 24 and 20 days were preliminarily studied by water culture. The main results of this study were as follows: 1) the main results of this study were as follows: 1) the main results of this study were as follows: after 24 hours of medium and short term stress with different concentrations of pb2 and CD _ 2, the results showed that the concentration of CD _ 2 was increased with the increase of pb2 ~ (2 +). Low concentration of pb2 could promote the elongation of root tip and high concentration of Cd2 could inhibit root elongation. The content of MDA in root increased with the increase of pb2 CD 2 stress concentration, and with the increase of lead and cadmium concentration. The activity of superoxide dismutase (SOD), catalase (catalase) and peroxidase (POD) in root increased gradually. The results showed that the root of green apple could protect its membrane substance from peroxidation damage by increasing the activity of SOD- Cat. 2) the treatment of exogenous calcium was at high concentration of pb2. Under high concentration of Cd2 for 24 hours, compared with the lead without calcium and cadmium stress, the root was enriched in lead, the content of cadmium was significantly lower than that of the group without calcium, and the elongation of root was significantly higher than that of the group without calcium. The activity of pb2 in cadmium stress group was lower than that in lead group without calcium. The results showed that exogenous calcium supplementation had significant effect on high concentration of pb2. The toxic effect caused by high concentration of Cd2 was alleviated. (3) after 20 days of culture with different concentrations of pb2, CD _ 2, the content of cadmium was the highest in root, followed by stem and leaf, among which lead accumulated in root was the lowest. At the same time, in the analysis of the content of metallothionein in root, stem and leaf, it was found that the content of MT was the highest in root under pb2 + CD _ 2 stress, followed by the second in leaf and the lowest in stem, and along with lead, the content of metallothionein in root was the highest in root, and the lowest in stem under pb2 + CD _ 2 stress. The content of MT in roots, stems and leaves increased rapidly and then decreased slowly with the increase of cadmium concentration. The results showed that lead and cadmium induced the synthesis of MT in plants, which were used to complexate metal ions. In the analysis of chlorophyll content in leaves, it was found that chlorophyll content increased first and then decreased with the increase of Pb and CD concentration.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X173

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