不同品种白菜对镉的吸收差异以及外源锌、锰对蔬菜吸收镉的影响

发布时间：2018-04-09 10:12

本文选题：蔬菜　切入点：镉含量　出处：《南京农业大学》2015年硕士论文

【摘要】：随着现代经济社会的高速发展,工业生产中废气、废水的不断排放,以及日常生活中大量汽车尾气的排放,世界范围内很多地区农业土壤重金属污染尤其是镉(Cd)污染日益加剧。蔬菜是人们日常生活中必不可少的一种经济作物,Cd能够通过蔬菜进入食物链进而进入人体,在人体中积累,达到一定剂量后会造成骨质疏松、肾功能衰竭,甚至引发癌症等疾病,对人体健康产生极大危害。蔬菜Cd污染还对农产品品质构成威胁,制约了农业可持续发展。在土壤Cd污染条件下,如何通过有效措施,减少蔬菜对于Cd的吸收,降低Cd对人体健康的威胁,成为亟需解决的重要问题。锌(Zn)和锰(Mn)都是对人体有益的微量元素,且Zn和Cd属于同一主族,具有相似的化学性质,已有研究表明,水溶态Zn进入土壤后,能够与土壤中的Cd竞争植物细胞膜上的转运体,降低植物对Cd的吸收和积累。因此,本文选择了多个品种的蔬菜,采用水培、盆栽、大田试验研究了不同品种蔬菜对Cd吸收能力的差异以及添加外源Zn、Mn对于蔬菜吸收积累Cd的影响。主要结果如下:通过水培试验研究不同品种白菜(Brassica rapa ssp.pekinensis and ssp.chinensis)对于Cd吸收、积累能力的差异。结果表明,在营养液中添加0.5μmol/LCd处理的条件下,所选10个白菜品种中高脚匙羹白、Chiifu、CGN15199等3个品种根部Cd含量显著高于其他品种,吸收的Cd大部分积累在根部;而津绿75、大青麻叶、L58DH等3个品种从根部向地上部转运的Cd显著高于其他品种。通过人工模拟1 mg·kg~(-1)的Cd污染土壤的盆栽试验,研究添加不同浓度的外源Zn、Mn对于白菜(Brassica rapa ssp.pekiensis)吸收Cd的影响。结果显示,与对照相比,添加了 1 mg·kg~(-1) Cd处理之后的所有处理白菜中Cd含量均显著提高,添加高浓度Zn处理(10mg·kg~(-1))的白菜地上部Cd含量与只添加Cd处理的Cd对照组相比显著降低,而添加低浓度Zn处理以及添加所有Mn处理的白菜地上部Cd含量与Cd对照组相比无显著差异。得到结论,在1mg·kg~(-1)的Cd污染条件下,添加一定浓度的外源Zn能显著增加土壤中有效态Zn含量,减少白菜地上部Cd的含量。结合盆栽试验结果,选择天津市城郊具有Cd污染风险的蔬菜田进行大田试验,研究在田间实际生产条件下外源Zn、Mn对蔬菜吸收Cd的影响以及该地区蔬菜中重金属的主要来源。结果表明,天津市城郊蔬菜农田土壤中Cd含量并未超过土壤环境质量标准,蔬菜中重金属含量也符合食品安全国家标准食品中污染物的限量标准。通过蔬菜中Ti含量与其他重金属含量的比例关系,以及蔬菜与大气沉降物中各重金属含量的比例关系拟合方程计算得到大气沉降及土壤扬尘对蔬菜中Cd、As、Pb、Cr等几种主要重金属含量贡献率分别达到了 33.7%、83.7%、72.8%和71.0%,得出该地区蔬菜中As、Pb、Cr等重金属的主要来源是大气沉降和土壤扬尘的结论,通过清洗能够有效降低蔬菜中重金属含量,及重金属对人体健康的威胁。
[Abstract]:With the rapid development of modern economy and society, the emission of waste gas and waste water in industrial production, as well as the emission of a large amount of automobile exhaust gas in daily life, the pollution of heavy metals in agricultural soil, especially cadmium and cadmium (CD), in many regions of the world is becoming more and more serious.Vegetables are an indispensable cash crop in people's daily life. They can enter the food chain through vegetables and then enter the human body. When they reach a certain dose, they can cause osteoporosis and renal failure.Even lead to cancer and other diseases, to human health has great harm.CD pollution in vegetables also posed a threat to the quality of agricultural products and restricted the sustainable development of agriculture.Under the condition of CD pollution in soil, how to reduce the absorption of CD in vegetables and the threat of CD to human health through effective measures has become an important problem that needs to be solved.Zn (Zn) and mn (mn) are beneficial trace elements to human body, and Zn and CD belong to the same main group and have similar chemical properties. It has been shown that when water-soluble Zn enters the soil, it can compete with CD in soil to compete with the transporter on plant cell membrane.The absorption and accumulation of CD in plants were decreased.Therefore, in this paper, the effects of exogenous Zn ~ (2 +) mn on CD uptake and accumulation in vegetables were studied by water culture, pot cultivation, and field experiments, and the effects of exogenous Zn ~ (2 +) mn on CD uptake and accumulation in vegetables were studied.The main results were as follows: the differences of CD uptake and accumulation ability of Brassica rapa ssp.pekinensis and ssp. chinensis were studied by hydroponics.The results showed that the CD contents in the roots of the 10 Chinese cabbage cultivars were significantly higher than those of the other varieties, and most of the CD absorbed was accumulated in the roots.The CD transport from root to shoot of three cultivars Jinlu 75 and L58DH were significantly higher than that of other varieties.A pot experiment was conducted to study the effects of different concentrations of exogenous ZnN mn on CD uptake by Brassica rapa ssp.pekiensis (Brassica rapa ssp.pekiensis).The results showed that compared with the control, the CD content of all the treatments increased significantly after the addition of 1 mg / kg of CD. The CD content of the above ground part of the cabbage treated with 10 mg / kg of Zn was significantly lower than that of the control group, and that of the control group was significantly lower than that of the control group.However, there was no significant difference in CD content in shoot of Chinese cabbage treated with low concentration Zn and all mn treatments compared with CD control group.It was concluded that under the condition of CD pollution with 1mg (kg ~ (-1)), adding a certain concentration of exogenous Zn could significantly increase the content of available Zn in soil and decrease the content of CD in the shoot of Chinese cabbage (Brassica campestris L.).Based on the results of pot experiment, the vegetable fields with CD pollution risk in the suburbs of Tianjin were selected to study the effects of exogenous Zn ~ (2 +) mn on the uptake of CD in vegetables and the main sources of heavy metals in vegetables in this area under the actual production conditions in the field.The results showed that the content of CD in vegetable farmland in the suburbs of Tianjin did not exceed the standard of soil environmental quality, and the content of heavy metals in vegetables was in line with the limit standard of contaminants in food and food of national food safety standard.The relationship between Ti content and other heavy metals in vegetables was studied.The main sources of heavy metals, such as Ash, PbN, Cr and so on, in vegetables in the region are the conclusion that atmospheric deposition and soil dust are the main sources.Cleaning can effectively reduce the content of heavy metals in vegetables and the threat of heavy metals to human health.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X53;X56

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