【作者】 李翠兰；

【导师】 吴景贵；

【作者基本信息】 吉林农业大学 ， 土壤学， 2011， 博士

【摘要】 城市土壤重金属污染日趋严重,特别是铅(Pb)污染已导致城市儿童血Pb含量升高。植物修复技术以其低成本和环境友好等优点成为污染土壤修复行之有效的方法,成为国内外研究的热点。超积累植物筛选是植物修复能否成功的关键,也是植物修复技术的难点所在。本文以长春市为例,首先对城市表层土壤理化性质与Pb污染进行评价；其次通过分析12个绿化植物叶片对铅的吸收量,筛选出对大气铅吸收力强的植物种,为城市土壤铅污染的植物修复提供理论依据；以杨树叶片为代表,初步判断植物大气铅污染等级；土壤Pb污染主要来源于交通污染等人为活动,人们往往忽略了自然落叶或人为施用有机肥带给土壤的影响,因此初步探讨了城市土壤中外源有机物料对Pb吸附的影响,充分肯定了花卉植物修复具有巨大潜力；然后通过砂培、水培和土培试验,研究了32种常见花卉植物(包括一串红、绣线菊、紫花玉簪、鸭跖草、马蔺、石碱花、石竹、波斯菊、福禄考、四季海棠、金鱼草、金盏菊、天竺葵、雁来红、红王子锦带、紫茉莉、蜀葵、茶花凤仙、百日草、万寿菊、大丽花、八仙花、月季、美人蕉、银边天竺葵、彩叶草、金边天竺葵、矮牵牛、孔雀草、八宝景天、君子兰、射干)对Pb胁迫的生长反应及Pb在植物体内的富集特征,筛选出了Pb富集能力较强且适于北方种植的的花卉品种,为探索花卉植物修复城市Pb污染土壤的技术提供理论和实践依据。主要研究结果归纳如下：1、以长春市为例,对城市表层土壤的理化性质与Pb污染评价结果表明,城市表层土壤物理性质略差,但多数有利于植物根系的正常生长；化学指标总体上处于较高水平。长春城区表层土壤Pb含量差异性很大,变幅为18.7～125.8 mg·kg-1,平均含量为57.1 mg·kg-1。采用Pb污染指数法和地积累指数评价法,长春城区表层土壤Pb总体上处于轻度向偏中度污染水平。2、通过14个主要街路两侧12种植物叶片中Pb的含量测定,采用单项污染指数法计算污染指数进行大气质量等级评价结果表明：运用聚类分析得出,12种植物对Pb吸收能力最强的是绣线菊,其次是杨树、油松、矮牵牛和彩叶草；而对Pb吸收能力最弱的树种是榆树、女贞、小叶女贞、八宝景天。采用单项污染指数评价法计算大气质量等级,长春市红旗街和同志街大气Pb污染达到严重污染程度,火车站北口属于重度污染区,会展大街已达到中度污染,人民大街和南湖大路属于轻度污染区,无污染的是凯旋路、前进大街和延安大路。3、城市土壤外源有机物料原样及其HLA、HLM对Pb2+的等温吸附曲线研究结果表明,树叶、草坪草和牛粪原样及其HLA、HLM对Pb2+的吸附量随平衡溶液中Pb2+浓度的增加而增加；在相同初始浓度下,对于Pb2+的吸附量的顺序是树叶>牛粪>草坪草,对于同一有机物料来说,草坪草、树叶对Pb2+的吸附量的顺序是HLM>HLA>原样,HLA>HLM>原样。各组分的吸附等温线可以用Freundlich、Langmiur和Temkin方程很好的描述,且都呈显著线性相关,且与吸附等温曲线所表述的规律性一致,最大吸附量的顺序为HLA>HLM>原样。4、种子萌发试验分析结果显示,供试花卉植物中对Pb胁迫的耐性最强的是马蔺种子,其次是百日草种子和紫茉莉种子,耐性最差的是黑心菊种子。与对照相比,孔雀草和百曰草的根长分别下降了66.2%、55.1%,黑心菊下降了85.2%。说明种子幼根对Pb的耐性最强的花卉是孔雀草和百日草,最弱的是黑心菊。Pb胁迫对萌发后幼苗生长影响研究进一步证实植物根系对Pb的耐受能力较强的四种为马蔺、茶花凤仙、百日草和孔雀草,强弱顺序为马蔺>茶花凤仙>百日草>孔雀草。5、水培试验结果表明,供试花卉植物中四季海棠、百日草、紫茉莉和紫花玉簪的地上部最大Pb含量达到了超富集植物的临界含量标准,并且所有处理中它们的地上部Pb含量和富集系数数值最大,均显著高于其它花卉植物。供试花卉植物中,Pb转移系数最高值可达0.8以上的有四季海棠、百日草、紫茉莉、紫花玉簪和鸭跖草,并且百日草在200 mg Pb/L时的转移系数仍高于100 mg Pb/L时的转移系数。这说明四季海棠、百日草、紫茉莉、紫花玉簪和鸭跖草不仅对Pb胁迫具有较强的耐性,而且具有较高的Pb富集能力和转移能力。6、土培试验结果表明,1)供试花卉植物中,紫茉莉、蜀葵、四季海棠和茶花凤仙的地上部最大Pb含量都超过了100 mg-kg-1,其顺序为紫茉莉>蜀葵>四季海棠>茶花凤仙,并且它们的地上部Pb含量和Pb富集系数均显著高于其它花卉植物。2)供试花卉植物中,Pb转移系数最高值可达0.45以上的有紫茉莉、银边天竺葵、金边天竺葵、八宝景天,同时它们高浓度Pb处理下的转移系数均显著高于低浓度的。从花卉植物地上部修复能力来看,四季海棠的修复效率和Pb迁移总量最高,其次是紫茉莉、蜀葵、茶花凤仙、万寿菊、百日草,但都没有超过0.2%。3)综合以上研究结果可知,紫茉莉不仅对Pb胁迫具有较强的耐性,而且具有较高的Pb富集能力和转移能力,在Pb污染土壤的修复方面具有较大的应用价值。从花卉植物地上部修复能力来看,四季海棠、紫茉莉、百日草、茶花凤仙对Pb污染土壤有良好的修复潜力,蜀葵、茶花凤仙和万寿菊的修复潜力亦不可忽视。综上所述,通过系统研究适于长春市种植的32种常见花卉植物对Pb的生长反应及富集特征,从中发现了4种具备Pb超富集潜力的花卉植物,即四季海棠、百日草、紫茉莉和紫花玉簪,这4种花卉植物的Pb富集量均超过1000 mg-kg-1,富集系数均大于1,证明能够从花卉植物中筛选出对Pb具有较强耐性和富集能力的品种,利用花卉植物进行Pb污染土壤的修复是可行的,在降低土壤Pb含量的同时美化了城市环境,这为长春市Pb污染土壤的修复提供了新的模式。更多还原

【Abstract】 Heavy metal contamination in the urban soil is become increasingly. Especially, lead (Pb) pollution has caused a serious increase in blood Pb levels for urban children. Phytoremediation, which is of features for low cost and environmentally friendly, have been an effective method of contaminated soil remediation, and attracted great attention for domestic and foreign scholars. The screening of the hyperaccumulator is the key of phytoremediation, which is also the difficult point of phytoremediation. On the basis of exploration on the mechanism of urban soil lead contamination, the growth responses and accumulation characteristics of 32 common ornamental plants, including Salvia splendens Ker-Gawler, Spiraea salicifolia L., Hosta plantaginea Aschers, Commelina communis L., Iris lactea, Saponaria officinalis, Dianthus chinensis L., Cosmos bipinnatus Cav., Phlox drummondii Hook., Begonia semper. norms, Antirrhinum majus L., Calendula officinalis, Pelargonium hortorum, Amaranthus tricolorL., Weigela florida cv.Red Prince, Mirabilis jalapa Linn., Althaea rosea, Impatiens balsamena. L, Zinnia L., Tagetes erecta L., Dahlia pinnata Cav., Hydrangea macrophylla (Thunb.)Seringe, R chinensis, Canna indica, Pelargonium hortorum Bailey. var. vareigata, Coleus blumei, Pelargonium, Petunia hybrida Vilm, Tagetes patula L., Sedum spectabile Boreau, Clivia and Rhizoma Belamcandae, were studied through the sand culture, hydroponic culture and soil culture experiment. The ornamental species, which is suitable to growth in northern city of China and has high Pb enrichment ability, were screened out. This aimed at exploring the suitable phytoremediation technology of Pb contaminated soil using ornamental plants. The main results are summarized as follows:1. Take Changchun city as an example, the physical and chemical properties and Pb pollution evaluation of surface urban soils positioned were carried out. The results showed that the physical properties of urban soil were slightly worse, and the chemical indicators were in general at a high level. Most of the soils were benefit to the normal growth of plant roots. The Pb content of urban green earth soil in Changchun city varied widely, ranged from 18.7-125.8 mg/kg with an average of 57.1 mg/kg. With lead pollution index and accumulate index method, the Pb content in urban green earth soil of Changchun city generally between the light and moderate pollution levels.2. Both sides of the main street through 14 of the 12 species leaves the determination of lead, calculated using the single pollution index of the quality level of atmospheric pollution index evaluation showed that:the use of cluster analysis,12 species most capable of lead uptake Is Spiraea, followed by leaf boxwood, pine, Petunia and Coleus; while the weakest absorption of lead is the elm trees, privet, Ligustrum leaf, Eight Sedum. Use of single pollution index level of air quality assessment method, Hongqi Street, Changchun City, and comrades Street atmospheric lead pollution to serious pollution, the railway station north exit of the heavily polluted area are lead, Exhibition Avenue has reached moderate pollution, the people are light Avenue and South Lake road Degree of contaminated areas, pollution is Kaixuan, forward Avenue and Yan’an road.3. Adsorption isotherms of Pb2+ onto turfgrass, cattle manure and leaves, its HLA and HLM added in urban soils show that the adsorption capacity data increases at the same increasing Pb2+ concentrations of equilibrium. On the conditions of Identical initial concentration, he adsorption capacity data is following:leaves>cattle manure>turfgrass. On the conditions of Identical initial concentration, the adsorption capacity data is following: HLA>HLM>organic matters. The adsorption capacity data is well correlated by both Langmuir and Freundlich isotherm models, attain remarkable linear correlation. As the same as the regularity of adsorption isotherms, the adsorption capacity data is the same following:HLA>HLM> organic matters.4. Seed germination test results show that the tested plants flowers on lead tolerance Iris seed is the strongest, followed by zinnia seeds and seeds of Mirabilis, patience is the worst seeds Rudbeckia hirta. Compared with the control patula and zinnia root length decreased by 66.2%,55.1%, down 85.2% Rudbeckia hirta. That the patience of the seed radicle of the strongest lead is patula and zinnia flowers, the weakest is Rudbeckia hirta. Pb stress on seedling growth after germination studies confirm the tolerance of plant roots on the ability of lead of four to Iris, Camellia impatiens, zinnia, and maidenhair, the strength of the order of Iris> Camellia impatiens> Zinnia> maidenhair.5. Results from the hydroponic experiment showed that the highest Pb contents in shoot of Begonia semperflorens, Zinnia elegan, Mirabilis jalapa. and Hosta ventricosa reached the critical standard of Pb hyperaccumulating plant. And the Pb content and bioaccumulation coefficient of the 4 ornamental plants was significantly higher than that of the else tested ornamental plants. Among the ornamental plants tested, the highest Pb translocation factor of Begonia semperflorens, Zinnia elegan, Mirabilis jalapa., Hosta ventricosa and Commelina communis were above 0.8. Meantime, the TF of Zinnia elegan was still higher for 200 mg Pb/L than for 100 mg Pb/L. These results indicated that Begonia semperflorens, Zinnia elegan, Mirabilis jalapa., Hosta ventricosa and Commelina communis have stronger tolerance under Pb stress and higher ability of enrichment and translocation for Pb.6. Results from soil culture experiment showed that:1) the tested plants flower, Mirabilis, hollyhock, impatiens Camellia Begonia and the maximum shoot Pb concentrations are more than 100 mg/kg, the order of Mirabilis> hollyhock> Begonia> Camellia impatiens, and they shoot Pb content and Pb enrichment factors were significantly higher than other plants.2) for the test in the flowering plants, Pb transfer coefficient than the maximum value of up to 0.45 with Mirabilis, Silver geranium, Geranium Phnom Penh, eight treasures Sedum, while they are treated with high concentrations of the transfer coefficient of Pb were significantly higher than the low concentration The. Shoot from the repair capacity of flower plants of view, the repair of Begonia efficiency and the highest total Pb migration, followed by Mirabilis, hollyhocks, camellias impatiens, marigold, zinnia, but did not exceed 0.2%.3) The above study results, Mirabilis not only has a strong tolerance to Pb stress, and with high capacity and transfer capacity of Pb enrichment, remediation of polluted soil in Pb has great application value. Shoot from the repair capacity of flower plants of view, Begonia, Mirabilis, zinnia, impatiens on Pb contaminated soil Camellia good repair potential, hollyhock, impatiens, and marigold Camellia repair potential should not be ignored.In summary,4 ornamental plants with feature of Pb hyperaccumulation potential, that is, Begonia semper. norms, Zinnia L., Mirabilis jalapa Linn. and Hosta plantaginea Aschers, were found through systematic study the growth responses and accumulation characteristics of Pb for the 32 common ornamental plants suitable planting in Changchun city. The Pb concentrations for the above 4 ornamental plants were all over 1000mg/kg, and the enrichment factors were all greater than 1. This proved that the screen of the ornamental plants with strong patience and high accumulation ability to Pb is feasible. Thus, it is suitable for the restore of Pb contaminated soils using the ornamental plants. At the same time of reducing the Pb content of the soil, the urban environment is beautified. This provides a new mode for the remediation of Pb contaminated soils in Changchun city.更多还原