【作者】 郑洁敏；

【导师】 陈子元； 唐世荣；

【作者基本信息】 浙江大学 ， 生物物理学， 2005， 博士

【摘要】 土壤中重金属和放射性核素污染日趋严重,植物修复技术以其成本低、环境友好等特点成为污染土壤治理行之有效的方法之一,引起了国内外学者的高度重视。超积累植物是植物修复技术的关键,筛选和发现超积累植物是植物修复技术的难点所在。提高超积累植物对无机物的吸收能力、增加其地上部生物量、加速其生长速率,进而提高植物修复的效率是又一个值得研究的问题。针对上述问题,本论文研究了苋科植物、蕨类植物、印度芥菜和向日葵对Cu和/或¹³⁴Cs的忍耐、吸收、运输和积累的特点;同时,研究了土壤中施加添加剂和提高CO₂气体浓度对植物吸收¹³⁴Cs和/或Cu的影响,旨在探索¹³⁴Cs和/或Cu污染土壤高效植物修复的技术。主要研究结果归纳如下: 1.选用富钾植物集中的苋科植物——籽粒苋、苋菜、青葙、千日红、千日白和寿昌苋,水培42天后,进行3种不同¹³⁴Cs活度处理(2.775×10⁵ Bq盆^-1、5.55×10⁵ Bq盆^-1、1.11×10⁶ Bq盆^-1),1周后收获并分析植物各部位的¹³⁴Cs比活度。结果表明,6种苋科植物均表现出对¹³⁴Cs具有较强的吸收和积累能力,而且¹³⁴Cs主要积累在植物的地上部。同种植物地上部的¹³⁴Cs比活度与溶液中¹³⁴Cs活度有关,¹³⁴Cs活度越高,植物中¹³⁴Cs比活度越大。籽粒苋地上部的烘干重显著高于其他5种苋科植物,因此尽管其地上部¹³⁴Cs比活度相对较低,但是其地上部从¹³⁴Cs水溶液中去除的¹³⁴Cs总量在6种植物中最大,表现出很高的¹³⁴Cs去除率。苋菜和青葙地上部具有较高的¹³⁴Cs积累量、转移能力和较大的生物量,也表现出在¹³⁴Cs污染土壤植物修复技术中潜在的利用价值。 2.在水培实验的基础上,将对¹³⁴Cs去除能力较强的籽粒苋和苋菜播种在不同¹³⁴Cs污染(5.55×10⁵ Bq盆^<sup>-1、1.11×10⁶ Bq盆^-1和1.665×10⁶ Bq盆^-1)的土壤中,发芽并生长共49天后测定植物地上部¹³⁴Cs的比活度。结果表明,籽粒苋和苋菜地上部¹³⁴Cs比活度随着土壤中¹³⁴Cs比活度的增加而增加,两种植物对¹³⁴Cs均表现出较高的富集能力,是¹³⁴Cs污染土壤植物修复较好的材料。实验同时研究了26种化学添加剂对土壤中¹³⁴Cs的解吸能力。在供试的26种添加剂中,（NH₄）₂SO₄溶液对土壤中¹³⁴Cs具有最强的解吸能力。土壤中施加0.4 molL^-1的（NH₄）₂SO₄溶液减少了苋菜地上部对¹³⁴Cs的总去除量,但对籽粒苋地上部¹³⁴Cs总去除量无显著性影响。说明在土壤中施加（NH₄）₂SO₄对不同的植物去除污染土更多还原

【Abstract】 Soil pollution by heavy metals and radionuclides has been a problem in our society and the situation is deteriorating with increasing human activities. Phytoremediation, with the advantage of low cost and environmental friendliness, is one of the important techniques in removing inorganic contaminants from soils. Screening of hyperaccumulators, plants that accumulate high levels of heavy metals, is prerequisite for the technique. It is also critical for effective phytoremediation to explore ways to increase the content of contaminants in the hyperaccumulators by means of, for example, promotion of uptake, growth and hence biomass, especially of shoots. The present research was focused on the investigation of capability of plants from Amaranthaceae and Pteridophyte in removing radiocesium 134 and/or copper from soils respectively. Both field and greenhouse studies were carried out in order to characterize the tolerance, uptake, translocation and accumulation of these two inorganic contaminants in the two respective families of plants. Furthermore, we examined the effect of soil amendment and elevated CO₂ concentration on the uptake of ¹³⁴Cs and Cu by plants so as to make phytoremediation more effective. Major results are generalized as follows:1. Six species of plants from the Amaranthaceae — Amaranthus cruentus L., Amaranthus tricolor L., Amanranthns paniculatus L, Celosia argentea L., Gomphrea globasa L. and Gomphrea globosa cv. Alba — previously known to be capable of hyper-accumulating potassium, were grown in nutrient solution for 42 days before treatment with ¹³⁴Cs at 3 different levels of radiaoactivities （2.775×10⁵ Bq/pot, 5.55 × 10⁵ Bq/pot and 1.11 × 10⁶ Bq/pot）. Plants were harvested 7 days after treatment and different plant parts analyzed for ¹³⁴Cs specific activities. All six plant species exhibited comparatively high ability in ¹³⁴Cs uptake and accumulation. Most of ¹³⁴Cs were found to accumulate in shoots and the shoot ¹³⁴Cs specific activity was positively correlated with the ¹³⁴Cs activity in nutrient solution. Amaranthus cruentus L., with the highest shoot biomass but a lower activity of ¹³⁴Cs among the six species, resulted in the highest removal rate in terms of total activities of ¹³⁴Cs in shoots. In addition, both Amaranthus tricolor L and Celosia argentea L. displayed high values of Bioconcentration Factor （BF; the ratio of heavy metal content in plant to that in medium） in leaves, therefore they could also be valuable for use in phytoremediation of ¹³⁴Cs- contaminated soils.2. A. tricolor and A. cruentus, which were shown to remove ¹³⁴Cs from solutionefficiently, were sown in soil contaminated artificially with 3 levels of 134Cs activities （5.55 × 10⁵ Bq/pot and 1.11 × 10⁶ Bq/pot and 1.665 × 10⁶ Bq/pot）. Plants were harvested 49 days after sowing and analyzed for 134Cs specific activities. In accordance with hydroponics, plants grown in soils with increasing Cs activities showed increasing 134Cs activities in shoots. Experiments were also carried out to determine the effect of 26 chemicals on 134Cs desorption from soil. （NH4）2SO4 was found to have the highest efficiency to enhance the desorption of 134Cs. （NH4）2SO4 application reduced the biomass production of both species and caused a decrease of the total 134Cs removal by A. tricolor shoot but had no significant effect on the total 134Cs removal by A. cruentus shoot, implicating that （NH4）2SO4 might play quite different roles in different plant species with respect to 134Cs removal by shoots.3. Field study revealed that Petridium revolution was one of the predominant plant species grown vigorously on the copper mining spoils in Yunnan province. The soils where P. revolution was growing contained 201-7554 mg kg-1 of Cu, whereas the above ground part of P. revolutum 30⁵67 mg kg-1, and the remaining parts of P. revolutum accumulated 36¹723 mg kg-1 of Cu. The BFs of P. revolutum fronds varied from 0.03².96, and those of the underground part varied from 0.06³.67. The Translocation更多还原