【作者】 李福燕；

【导师】 漆智平； 唐树梅；

【作者基本信息】 海南大学 ， 作物栽培与耕作学， 2010， 博士

【摘要】 土壤是人类赖以生存的自然环境和农业生产的重要资源,世界面临的粮食、资源和环境问题与土壤密切相关,目前重金属污染成为危害土壤的主要因素。本文以土壤-植物为系统,采用生态学、地理科学、植物生态等多学科协同及野外调查-实验测试-栽培试验-综合研究等方法。开展了海南岛农用地重金属污染现状评价,重点对三亚市的重金属污染现状进行调查与评价,并对热带地区水稻的Cd胁迫耐性生理进行了初步研究,以期为海南岛农用地利用和优化开发以及污染防治提供科学依据。主要结论如下：1海南省农用地重金属污染现状及其评价本文利用地统计学方法及地理信息系统(GIS),分析海南岛农用地中的Hg, Cd, Cr,Pb和As等5种重金属的污染状况及空间变异性分析。结果表明Hg, Cd, Cr, Pb和As等5种重金属的平均含量均为超过国家环境质量二级标准(GB15618-1995)；但研究区土壤中Hg、Cd、Cr三种重金属元素含量的最大值均超过了国家土壤环境质量的二级标准,并分别达到了1.63 mg·kg-1、0.64mg·kg-1、586.70 mg·kg-1; Hg、Cd、Cr和Pb4种重金属含量的变异函数理论模型符合指数模型,元素As含量的变异函数理论模型符合高斯模型；相关性表明Hg和Pb空间相关程度弱,显示出其含量受成土因素的影响较大；Cd、Cr和As空间相关程度中等,显示出其含量受外源污染的影响较大；通过Kriging插值方法得出了海南岛上该五种土壤重金属的插值梯度分布图,显示出在海南岛上外源性重金属污染在工业区为最严重。土壤有机质含量、pH值和土壤中重金属含量相关关系结果表明：海南省农用地土壤有机质含量总体上处于中下水平,全省有机质平均含量为22.99%,各地区之间含量差异较大,土壤pH平均值为5.20；土壤重金属含量与土壤理化性质间的关系复杂：有机质含量与Hg、Cd、Cr含量呈极显著正相关,与Pb、As含量呈显著相关,而pH与Hg、Cr呈负相关,与Cd、Pb、As呈显著正相关。2三亚市果蔬地及果蔬重金属污染现状及其评价通过野外调查采样,采用标准对比法和地质累积指数法,评价了三亚市果蔬地表层土壤重金属的污染状况。结果表明：土壤中Hg、Cd、Cr、Pb和As5种重金属的积累不显著,其平均值均未超过国家环境质量二级标准(GB15618-1995)；但Hg、Pb和Cd的平均值高于海南岛农用地的自然背景值,表明存在区域轻度污染；Cr、Hg、Pb和As4种重金属元素的变异系数均>1,表明土壤中Cr、Hg、Pb和As的分布极不均匀。同时利用地理信息系统(GIS) Krging插值方法得到了5种重金属的空间分布图,显示出不同重金属元素的空间分异特征,为三亚市果蔬地的可持续开发利用提供指导。瓜菜重金属含量检测,采用国家蔬菜卫生质量标准计算单项因子污染指数和综合污染指数,通过内梅罗污染指数标准进行评价,同时对污染源进行分析。结果表明,三亚果蔬整体上为清洁无污染水平,四种重金属(Zn、Cu、Pb、Cd)在果蔬中的综合污染指数为0.60,根据内梅洛污染指数评价属安全无污染水平,不同种类的瓜菜对重金属的富集含量差异较大,各类果蔬的综合污染指数从大到小为：叶菜类>豆类>瓜类>根茎类>茄类>水果类,叶菜类较其他瓜菜容易富集叶菜类达到轻度污染,综合污染指数达1.19,豆类和瓜类的为尚清洁接近污染水平,综合污染指数分为0.85和0.79,其它果蔬为清洁水平。3不同水稻品种对镉胁迫的响应差异以热带地区主栽品种博优225和矮糯为材料,采用盆栽试验的方法研究了水稻土中重金属镉(Cd)的浓度对水稻生长及镉富集的影响以及镉在水稻植株的分布情况及不同水稻品种对土壤外源重金属Cd胁迫的耐性机理。研究结果表明：在各个浓度镉胁迫下,根、茎叶、稻壳、糙米相比,2个品种水稻都是根累积的镉含量要高于茎叶和稻壳、糙米,即根>茎叶>稻壳>糙米；在水稻的茎叶细胞中,镉主要分布在细胞壁,细胞可溶性成分,细胞器镉的分布量较少,即F1(细胞壁)>F3(可溶性部分)>F2(细胞器及膜部分)；随Cd浓度增加,茎叶中的Cd积累量极显著增加,各细胞组分中的Cd含量均显著增加；博优225与矮糯水稻在低浓度处理下所积累的Cd以氯化钠提取态、盐酸提取态,醋酸提取态为主,三者占总量的80%以上。随着Cd处理浓度的增加,矮糯与博优225氯化钠提取态相对含量降低,其绝对含量接近饱和,而醋酸提取态Cd的相对含量增加。博优225水稻与矮糯水稻相比,80%酒精提取态与残渣态Cd占总量的比例皆无明显变化。随着镉胁迫浓度的增加细胞膜受损的伤害程度越大,矮糯质膜透性略高于博优225；随着Cd浓度的升高水稻叶片丙二醛(MDA)、脯氨酸含量逐渐增加,且博优225的增加幅度明显大于矮糯随着镉浓度的提高；超氧化物歧化酶(SOD)和过氧化物酶(POD)活性均表现为上升趋势,且博优225明显高于矮糯；过氧化氢酶(CAT)活性呈下降趋势。表明同样条件下博优225受Cd毒害更严重。更多还原

【Abstract】 Soil is the indispensable environment for human survival and important resource for agriculture development. Food and environment problems facing the world are all closely related to soil and nowadays it is threatened by many factors, among which heavy metal pollution are the most serious one. In this study, soil-plant as an associated system. An integrated study method was accepted in this study, it includes ecological, geographical science, plant ecology, and also includes the experimental analysis, planting test and simulating test. The pollution of heavy metals on agricultural land in HaiNan. The research results provide scientific basis for optimization of development, farmland-use and pollution control of HaiNan. This study includes the following three correlative parts and summarizes the following results and conclusions.1 Pollution Status and contamination evaluation of heavy metals on farm land in Hainan IslandGeographical information system (GIS) combined with Geostatistics was applied to reveal the features of the spatial distribution of concentrations of heavy metal Hg, Cd, Pb, As and Cr on farm land in Hainan island. The results show that the average concentrations of the five metals are below the GradeⅡstandard of National environmental quality standard for soil (GB15618-1995), but the max contents of Hg、Cd、Cr were higher than the soil environmental quality standard, the concentrations of Hg、Cd、Cr were 1.63,0.64, and 586.70mg·kg-1.The theoretical semivariogram models of soil Hg, Cd, Cr and Pb fit for the Exponential model well. The spatial correlation of Hg and that of Pb are both weak, indicating that their concentrations are affected deeply by soil formation facts. The theoretical semivariogram model of soil As fits the Gaussian model well. The distribution spatial correlation of Cd, Cr and As is moderate respectly, indicting their concentrations are affected by the inputs from outside. The contour distrubition maps of the 5 heavy metals on farm land in Hainan island are obtained based on Kriging algorithm, showing that the heavy metal polutions caused by the inputs from outsides in industrial zones are most serious in Hainan island. Soil organic matter contents、pH and heavy metal contents of agriculture soils in Hainan were studied for relationships between soil organic matter content、pH and contents of soil heavy metals. Results showed that almost all the soil samples collected from Hainan Area organic matter contents were at middle or low levels with an average content of organic matter being 22.99%, but three parameters did vary much from site to site; an average pH value being 5.20. The results of correlation analysis showed that relationships between soil heavy metals and soil organic matter contents and pH were complicated.2 Pollution Status and contamination evaluation of heavy metals in orchards and vegetable gardens soil of Sanya CityVegetable security is important to our life, and it is absolutely necessary to set up city outskirt biogeocenose system. With industry and agriculture development, atmosphere, water and soil are getting more polluted. So vegetable is polluted in some degree. We measured and analyzed contents of heavy metals in vegetables and fruits and soils in Sanya of Hainan province. Heavy metal contamination condition of surface soil in orchards and vegetable gardens of Sanya City was evaluated by filed survey and sampling and by using standard comparison and Geoaccumulation index method. Result showed that the average values of the five heavy metals i.e., Hg, Cd, Cr, Pb and As, were all below GradeⅡof National environment quality standard (GB15618-1995). The variation coefficient of Cr、Hg、Pb and As were all> 1, which showed the distribution of four heavy metals were extremely uneven. However, the average values of Hg, Cd and Pb are higher than the background values of farm land in Hainan Island, showing slight pollution in certain areas. The spatial distribution of the five heavy metals were also obtained using Kriging algorithm approach, the spatial variation of soil pollution was obvious. The study provided guidance for sustainable development and utilization of orchards and vegetable gardens in Sanya city. Different evaluation methods and assessment standards of heavy metals were also used for comparison. Single factor pollution and comprehensive pollution index by national vegetable environmental quality standards and then evaluated by Nemero index, then analyzed the pollution source. The results showed that: mean concentrations of heavy metals in vegetables and fruits were not exceeded their corresponding natural-background values, no significant heavy metal pollution occurred in the study area as a whole. The enrichment of heavy metals in vegetables and fruits differed with their different physiological characteristics, growth time and sensitive degree to contamination, which comprehensive pollution index is green-leaves>Beans>melons> Rhizomas>Eggplants>fruits. Green-leaves were found slightly polluted, comprehensive pollution index is 1.19. Others comprehensive pollution index were less than 1.3 The response differences of different rice varieties in response to cadmium stress Cadmium(Cd)is important contaminants in agricultural soil and threatening agriculture and human health. With the development of industry and agriculture, the soil heavy metal cadmium pollution becomes more and more serious. In this study, two high-yielding rice cultivars currently used in the local production, Boyou 225, Short glutinous, A pot experiment with two Oryza sativa varieties in a paddy soil treated with five levels of cadmium was conducted to studied. Results showed that cadmium was not distributed uniformly in each part of rice plants. most of the absorbed Cd assembled in the root, the upper, the less, i.e. the law of distribution of Cd in different organs of rice should be:root> stem> rice husk> kernels. In rice roots and stems and leaves, cadmium is mainly distributed in the cell wall. Soluble components of cells, cell distribution of low cadmium. That is, F1 (Cell wall)> F3 (soluble part)> F2 (cell organelles and membrane part). Boyou 225 and short glutinous rice at low concentration under the deal with the accumulation of extractable Cd to sodium chloride, hydrochloric acid extractable, acid extractable mainly the three accounted for more than 80% of the total. With the increased concentration of Cd treatment, with short glutinous rice Boyou 225 extractable relative content of sodium chloride to reduce its absolute concentration close to saturation, and acetic acid extractable Cd increased relative content. Boyou 225 and short glutinous rice as compared to 80% alcohol extractable Cd and the residual proportion of the total are no significant changes.A pot experiment with two Oryza sativa Linnaeus varieties in a paddy soil treated with three levels of cadmium was conducted to study the physiological and biochemical and antioxidant enzyme system of the leaves. The results showed that with the increasing Cd concentration in soil increased the contents of malondialdehyde (MDA) and proline, which would be more pronounced in the Boyou225 than Short glutinous. The activities of SOD and POD were increased with the increased concentration of Cd, while the activities of catalase (CAT) were decreased. The activities of SOD and POD in the Boyou225 were significantly higher than those in the Short glutinous under relative higher Cd treatment. Our results indicated that with the Cd concentration increased caused the cell membrane. The rice varieties exhibited the genetic character on the Cadmium accumulation. The Cadmium contents of the grains increased with the increasing Cd concentration in soil. According to the state limit of cadmium in rice, the standard (GB 2762-2005), Content≤0.2 mg·kg-1. In this study, tropical paddy soil total Cd threshold were Boyou225 (Cd total)= 2.0 mg·kg-1; Short glutinous (Cd total)= 3.1 mg·kg-1. Therefore, for reducing the risk of the humanity to heavy metal, the rice varieties with the low capability of accumulating heavy metal in grains could be planted in a polluted soil.更多还原