【作者】 任立民；

【导师】 刘鹏；

【作者基本信息】 广西大学 ， 植物学， 2007， 硕士

【摘要】 本研究首先对广西大新县锰矿区植物进行了调查，接着对南方四种抗逆性较强的草本植物进行了超积累植物的筛选工作，并重点对锰超积累植物——美洲商陆进行了生理特性的研究，包括对根际土壤锰元素的活化、吸收及转运，抗氧化酶系统比较，叶绿素荧光分析、红外光谱分析等内容，从不同的水平和层次上研究了美洲商陆对锰毒的响应机制及耐性机理，现将主要研究成果总结如下：1、广西大新县锰矿污染的9种优势耐性植物中，蜈蚣草（Pteris vittata Linn．）对Mn、Zn、Ni都有较强的吸收能力；五节芒（Miscanthusfloridulus（Labill.）Warb.）、野茼蒿（Erigeron bonariensis L.）、酸模叶蓼（Polygonum lapathifolim L.）、加拿大蓬（Erigeroncanadensis L.）对Mn的吸收较强；蔓生莠竹（Nicrostegium gratum（Hack.）A.Camus.）、马唐（Digitaria sanguinalis（L.）Scop.）、海芋（Alocasia macrorrhiza（L.）Schott & Endl.）对Zn吸收较强；五节芒、加拿大蓬对Ni吸收能力显著。虽然这些植物对三种重金属的吸收均未达到超富集植物的要求，但作为污染土壤上的优势耐受性植物，相关研究仍具有一定意义。2、锰对水蓼、小飞蓬、杠板归和美洲商陆4种植物的生理特性都有明显的影响。在高浓度锰处理下(16000μmol．L^-1)，四种植物的质膜透性极显著升高（p＜0.01）、根系活力明显降低（p＜0.05）、地上部锰含量极显著增加（p＜0.01），除美洲商陆外的其他三种植物的丙二醛含量明显上升（p＜0.05），其中小飞蓬的变化幅度最大，美洲商陆的变化幅度最小。同时，该处理下水蓼、杠板归、美洲商陆的可溶性糖及叶绿素总量维持在一定水平，与对照相比无极显著差异（p＞0.01）。植物通过维持较低的质膜透性和丙二醛含量、较高的根系活力、稳定的可溶性糖及叶绿素含量来增强耐锰性，通过比较发现，美洲商陆的耐锰性最强，水蓼和杠板归的耐锰性较强，小飞蓬的耐锰性最差，并且本实验首次发现水蓼和杠板归均已达到锰超富集植物的标准。3、美洲商陆根茎叶中的全Mn含量随着处理浓度的升高而逐渐递增，尤其前期（第7天）叶片的Mn含量在锰处理为0.25g／kg时，便已达到超积累植物的标准，与之相对应，组织中的水溶态Mn所占比例也不断上升，最高Mn浓度下，叶片水溶态Mn含量达到19283.21mg／kg，占全锰含量的45.78％，这些变化又与根际土壤中Mn的活化有着密切关系，作为能被植物吸收的易溶态Mn和弱吸附态Mn均表现明显增加的趋势。4、锰毒胁迫下，SOD、POD、ASA—POD、PPO活性变化不一，其中，SOD活性变化不大；POD活性总体上会随着锰浓度的升高而逐渐上升，并在最高浓度下达到最大值，其活性是对照的507％；ASA-POD活性均有升高趋势，后期的变化幅度最大，最高浓度下的ASA—POD活性是对照的635％；PPO活性在前期对锰毒有着较强的敏感性，最高浓度下，其活性是对照的310％。综合以上分析发现，四种保护酶对锰毒的敏感性：ASA—POD＞POD＞PPO＞SOD。5、锰毒胁迫对叶绿素荧光各项指标影响不大，但高浓度的锰处理影响了部分光合特性，其中，F₀、Fm、qN均受到了抑制，综合两个时期看，第7d的光合特性要优于第14d。6、不同组织器官的傅里叶变换红外光谱（FTIR）图谱发生了变化。其中，茎组织在3336 cm^-1和2916 cm^-1处峰高先上升后下降，反映了有机物运输受阻情况的变化，即美洲商陆在低锰刺激下会产生大量有机物作为渗透调节物质来增强其耐锰性，高锰则抑制了有机物的分泌和运输；根和叶组织分别在2922 cm^-1和1606 cm^-1处表现不同变化趋势，但都反映了一个变化规律即低锰处理下美洲商陆分泌的有机酸不断螯合锰，随着锰毒害的加重，其羧酸螯合力变弱；根组织1732 cm^-1和1026 cm^-1、茎组织1028 cm^-1、叶组织1052 cm^-1和967 cm^-1处呈现差异性变化，但都与其膜脂过氧化有关；根组织1375cm^-1处峰高先上升后下降，可能与植物在细胞壁结构上增强抗逆性有一定关系，即低锰处理下细胞壁可能通过阳离子交换能力（CEC）的提高增强了耐锰性。以上说明，利用FTIR研究重金属超积累植物化学组分具有应用价值。更多还原

【Abstract】 Phytoremediation is defined as the use of plants to decontaminate and removepollutants from the environment. It has emerged as an alternative technique forremoving toxic metals from soil.In this study, a survey of nine plants growing on the soil polluted by manganese mine inDaxin County was firstly conducted.In addition, Four herbaceous plants, ConyzaCanadensis, Polygonum hydropiper, Polygonum perfoliatum and Phytolacca americanawere tested for their tolerance to manganese toxicity. At last, soil culture experimentswere carried out to characterize the mechanism of Mn tolerance in Phytolaccaamericana by means of a series of chemical, biochemical methods. The major resultswere summarized as follows:1. A survey of nine plants growing on the soil polluted by manganese mine in DaxinCounty was conducted. The result indicated that the exceptional-high concentrations ofMn were found to be the most important limiting factor for plant growth among threemetals （Mn, Zn and Ni）. Pteris vittata Linn, which roots showed good metal-enrichmentof Mn and Ni, turned out to have good tolerant ability of Mn, Zn and Ni according to theanalysis in the paper. In addition, Miscanthus floridulus （Labiil.） Warb, Erigeronbonariensis L, Polygonum lapathifolium L and Erigeron canadensis L were proved tohave good Mn-tolerant ability; Microstegium gratum （Hack.） A. Camus, Digitariasanguinalis （L.）Scop and Alocasia macrorrhiza （L.） Schott & Endl were Zn-tolerantplants while Miscanthus floridulus （Labill.） Warb and Erigeron canadensis L wereNi-tolerant plants. Further researches which are of some significance to these plants willbe still in process though no hyperaccummulators of these three heavy metals werefound in the survey. 2. Four herbaceous plants, Conyza Canadensis, Polygonum hydropiper, Polygonumperfoliatum and Phytolacca americana response differently to a wide range of Mn²⁺treatments. According to the hydroponic culture experiments, 16000μmol.L^-1Mn²⁺significantly （P＜0.05） promoted the contents of MDA （Phytolacca americana L wasexceptive）, MP and the overground Mn content when compared to the controlrespectively and these indexes in Polygonum hydropiper increased most whilePhytolacca americana rose less. Meanwhile, the soluble sugar （SS）, as well as thecontents of chlorophyll nearly maintained the same level as each control inConyza Canadensis, Polygonum perfoliatum and Phytolacca americana in comparisonwith Polygonum hydropiper, whereas, the content of soluble protein didn’t show theobvious tendency.The results also implied that Conyza Canadensis, Polygonum perfoliatum andPhytolacca americana could enhance the tolerance to Mn stress under hightreatments by maintaining lower contents of MDA and MP, higher root activity （RA）,steady contents of SS and chlorophyll and the three herbaceous plants, which weresatisfied with the standard of Mn phytoaccumulators can be expected during thephytoremediation application.3. The total Mn in plants’ tissues was positively correlated with Mn²⁺ treatment. Thetotal Mn in leaves（7d） was satisfied with the standard of Mn phytoaccumulators whenthe Mn treatments reached 0.25g/kg. Accordingly, the ratio of soluble Mn in tissuesincreased and accounted for 45.78％of total Mn while soluble Mn reached19283.21mg/kg with highest Mn treatments.. Meanwhile, there were positive correlationbetween Mn concentrations in plants’ tissues and Mn activation due to increasing Mn²⁺supply. As a result, The soluble sugar （SS）, as well as the contents of weakly-absorbedMn in soil significantly rose.4. The activity of POD, ASA—POD and PPO increased as the concentration ofManganese were enhanced while SOD activity changed slightly. Among four enzymes,ASA—POD had a widest variety range. The order of variety range wasASA—POD＞POD＞PPO＞SOD. There was a positive correlation between POD,ASA-POD, PPO and manganese resistance under Mn stress, but there was no significant correlation between SOD activity and manganese resistance.5. There wasn’t obvious toxic effect of Manganese on the chlorophyll fluorescencekinetic parameters of Phytolacca americana leaves, but F₀、Fm and qN were significantlyinhibited,Meanwhile, we can see that plants photosynthesis of the first stage was betterthan the seceond one.6. Using the roots, stems and leaves of Phytolacca Americana, absorption bandscorresponding to carbohydrates, ester and proteins varied differently. The absorptionband heights at 3000 cm^-1 and 2916 cm^-1 of stem tissues rose firstly then decreased,indicating the exudation and transporting situation of organic substances which servedas organic osmotic contents to enhance manganese tolerance under low treatments;Meanwhile, the band heights at 2922 cm^-1（roots） and 1606 cm^-1（leaves） which havedifferent tendency in accordance with Mn treatments showing that the capability tochelate Mn decreased under higher manganese concentration.In addition, the changes ofthe bands at 1732 cm^-1 and 1026 cm^-1（roots）, 1028 cm^-1（stems）, 1052 cm^-1 and 967cm^-1（leaves） differed from each other, suggesting that under the conditions of severe Mnstress the ex-oxidation of membrane lipid increased; Otherwise, the band heights at 1375cm^-1 increased firstly and then decreased, representing that the cell wall in, proved Mnresistance by increasing cation-exchange capacity（CEC）. The result also implied that itis practical to apply FIIR to the research comparing the chemical differences ofphytoaccumulators under metal treatments.更多还原