【作者】 孙静克；

【导师】 宗良纲；

【作者基本信息】 南京农业大学 ， 环境科学， 2007， 硕士

【摘要】 我国正面临土壤重金属污染日益严重的巨大压力，食品安全成了引起各界高度关注的十分重要的热点问题。本研究选择Cd、Pb这两种重金属，选择雪里蕻，通过生物盆栽实验，从生物学、环境毒理学的角度阐述植物吸收特征与食品安全性的关系，深入了解食品生产与土壤重金属污染的关系；探讨在污染土壤上通过适当的施肥管理措施达到既能够保持一定的产量水平，同时又能控制土壤重金属从土壤向作物体内转移，为指导环境质量与食品安全的建设提供依据。本文主要研究内容包括四个方面：(1)不同水质污水灌溉对雪里蕻生长及其吸收重金属的影响；(2)不同调控措施对雪里蕻生理生化特性的影响；(3)不同调控措施对雪里蕻光和特性的特性的影响；(4)不同调控调控措施对土壤重金属生物有效性的影响。通过不同水质污水灌溉的生物盆栽试验，可知雪里蕻受镉污染的受害症状主要表现为沿叶脉变色，失水失绿，受铅污染的受害症状主要表现在失绿萎蔫，有红褐色斑块，新叶卷曲。低浓度Cd、Pb对蔬菜生长都具有一定促进作用，当污染程度高于抑制浓度界线后，植株受损程度递增。Cd、Pb复合污染实验显示在一定的重金属浓度范围内，Cd对Pb的吸收有一定的抑制作用，Pb对镉Cd的吸收有一定的促进作用。在Cd污染土壤上，施用有机肥可以提高雪里蕻的产量、叶绿素含量和蛋白质含量。包膜柠檬酸处理对雪里蕻根系活力的提高作用最为显著，包膜柠檬酸和磷肥在提高产量的同时也显著降低植株对重金属的吸收。在Pb污染的土壤上，施用有机肥能提高雪里蕻产量、叶绿素含量、蛋白质含量和酶活性。在本试验条件下，Pb对植株根系活力的影响要大于Cd。有机肥的增产作用不仅与施用量有关，同时还与施用方式有关，而蛋白质含量仅与有机肥的施用量有关。在Cd-Pb复合污染的土壤中施用包膜柠檬酸，对雪里蕻体内蛋白质含量和根系活力的提高效果最为显著。施用磷肥可以显著降低植株对重金属Pb的吸收。土壤重金属Cd-Pb复合污染对雪里蕻根系活力的影响更大。不同施肥处理显著提高了雪里蕻对光强的适应范围，均能使净光合速率、光饱和点和表观量子效率显著升高，而使光补偿点降低。施用有机肥可以保持较高的P_n、LSP和AQY，而且与有机肥的施用量和施用方式都有关系，各施肥处理下F_v／F_m的值均大于0.8，表明作物均未引起光抑制。在镉污染土壤上，增施磷肥获得了最大的Pn和LSP值。在铅污染土壤上，施用磷肥获得了最大的Pn、LSP和AQY值。在不同施肥处理中，高量有机追肥处理可以使叶片PSⅡ的潜在的量子效率和PSⅡ原初光能转换效率保持最高水平。重金属生物有效性调控试验研究表明，施用有机肥使雪里蕻增产的同时，也提高了植物吸收重金属的风险。施用包膜柠檬酸在提高产量的同时也能抑制雪里蕻对Pb和Cd的吸收，但它对土壤中有效态重金属含量影响不明显，并且在形态分级分析时，包膜柠檬酸对Pb和Cd表现出的效应是不一致的，它能促进Cd从交换态(EXC)向残渣态(RES)转化，但对Pb作用刚好相反。因此，利用包膜柠檬酸修复土壤重金属污染必须考虑重金属的种类。施用磷肥能使重金属Cd、Pb从交换态(EXC)向残渣态(RES)转化，在增加雪里蕻产量的同时也抑制了重金属Cd、Pb的生物有效性。更多还原

【Abstract】 We are facing with the great pressure of heavy metals pollutions to the soil, and food safety is a crucial problem that caused serious concern from all sections. The study through pot cultivation, choose Cd and Pb, potherb mustard was used as a test material, discussed the relationship of absorptive character and heavy metals pollution from biology and environmental toxicology. The study took some treatments in order to discuss how to restrain heavy metals transfer to the plant from soil and keep a definite store of output maintimes. This could direct the environmental quality and offer basis for food safety.The study contains four sections: (1) growth-impact and toxic-symptom of single and compound pollution of Cd and Pb in soil of potherb mustard; (2) effects of different fertilizations on biochemical and psychotic response of potherb mustard; (3) effects of different fertilizations on photosynthetic characteristics of potherb mustard ; (4) effects of different fertilizations on biological effectiveness of heavy metals in soil.Through pot cultivation of different sewage irrigation, we know that potherb mustard would be turning color in nerve and drying out and without green in Cd-contaminated soil. And in the Pb-contaminated soil, the potherb mustard would be wilt and lost greenand leaves appeared reddish-brown patchs and new leaavs curls. That low concentration of Cd and Pb promoted growth of vegetables, and the potherb mustard woule be more poisoned when the concentration of heavy metals over the critical concentrations. The simulated test of compound contamination with Cd and Pb showed that, at a certain concentration, Cd inhibited potherb mustards to absorb Pb, and Pb promoted them to absorb Cd.On Cd-contaminated soil the use of organic fertilizer could stimulate the output, the chlorophyll content and protein content of potherb mustard. The use of lemon acid could stimulate the root activity of potherb mustard significance, and the use of lemon acid and phosphate could maintain the output high and reduce heavy metals of plants. On Pb-contaminated soil, the use of organic fertilizer could stimulate the output, the chlorophyll content, the protein content and activity of enzyme of potherb mustard. The heavy metals can restrain the root activity of plants, and the effect of Pb is more than Cd. The organic fertilizer could stimulate the output of plants and the effect of organic fertilizer related of its quantity and usage mode, but the protein content related to the usage mode of organic fertilizer only. On compound contamination soil, the use of lemon acid could stimulate the protein content and root activity of potherb mustard significance. The use of phosphate could reduce Pb content of potherb mustard and the effect of compound contamination to the root activity is more than single contamination.Different fertilizations could stimulate the adaptation to light of the plant. All the fertilizations could enhance the net photosynthetic rate (P_n) , light saturation point (LSP) and apparent quantum yield (AQY) and reduce the light compensation point (LCP) of the plant. The fertilizations of organic could maintain a higher P_n, LSP and AQY, and related to the method of the usage. The F_v/F_m of all the fertilizations was higher than 0.8, and this showed that the plants were not restrained by light. On Cd-contaminated soil the use of phosphate made the P_n and LSP largest. On Pb-contaminated soil the use of phosphate made the P_n , LSP and AQY largest. And the use of organic fertilizer made the PS II largest.The results showed that the use of organic fertilizer could enhance the risk of absorption of heavymetal. The use of lemon acid could reduce the content of heavy metals in the plant, and reduce the content of bioavailable Pb, but have no effect on the content of bioavailable Cd; so we should select a right kind of heavy metal when repair the soil with lemon acid. Phosphate fertilization could decrease the bioavailability of Pb and Cd very well, it made the heavy metals turn EXC to RES.更多还原