尾矿库植物根系发育的分形特征及对植物铀分布的影响

发布时间：2018-01-08 01:22

本文关键词：尾矿库植物根系发育的分形特征及对植物铀分布的影响　出处：《南华大学》2015年硕士论文　论文类型：学位论文

【摘要】：尾矿库是一个长期潜在的放射性污染源,它的环境治理是各国所面临的严峻问题,其中植物生态修复已成为学术界的热点。植物修复对尾矿生态环境质量的改善具有重要的现实意义,因此放射性污染物与植物的相互作用也得到了重视。植物根系分维数与体内累积铀含量关系的研究,可为植物修复的环境风险评价提供指导意义。本文以生长在尾矿之上的常见植物为研究对象,分析植物根系发育的分形特征,探究植物重量、长度与分维数之间的关系;研究尾矿库植物根系发育的分形特征对植物铀分布的影响关系,探寻适宜生长在尾矿库环境且对铀元素具有一定吸附优势的植物。本文得出结果如下:(1)茅草植物根系分维数介于1.3305到1.5214之间变化,小蓬草根系分维数介于1.25787到1.42802之间变化,碎米莎草根系分维数分别为1.44350和1.45141。生长在尾矿之上的茅草、小蓬草、碎米莎草植物的根系发育都具有典型的分形特征。茅草植物根系分维数对根系重量和长度有一定的影响关系,植物根系分形维数越高,植物根系长度以及重量也就越高。(2)在尾矿之上生长出来的茅草植物根系铀浓度明显高于生长于尾矿周边环境的根系铀浓度,说明尾矿库周边环境受污染影响较低。茅草和小蓬草体内铀浓度的整体变化趋势是随着植物根系分维数的增长而增长。植物根系分维数越高,根系越发达复杂,植物体内富集的铀元素越高。(3)茅草等四种植物根部铀浓度都明显高于茎和叶部位铀浓度,甚至有些植物的根系铀浓度是其他部位的上百倍。说明植物体内铀元素主要分布在植物根系。四种植物中碎米莎草根部富集的铀浓度最高,马唐其次,说明碎米莎草与马唐对铀元素具有一定的吸附优势。
[Abstract]:Tailings reservoir is a long-term potential source of radioactive pollution, its environmental management is a serious problem facing countries. Among them, phytoecological restoration has become a hot spot in academic circles. Phytoremediation has important practical significance to improve the ecological environment quality of tailings. Therefore, the interaction between radioactive pollutants and plants has also been paid attention to. The relationship between the fractal dimension of plant roots and the accumulation of uranium in the body is studied. It can provide guidance for environmental risk assessment of phytoremediation. This paper takes common plants growing on tailings as the research object, analyzes the fractal characteristics of plant root development, and probes into plant weight. The relationship between length and fractal dimension; The effects of fractal characteristics of root system development on uranium distribution in tailings reservoir were studied. In this paper, the results are as follows: 1) the root fractal dimension of the plant varies from 1.3305 to 1.5214. The fractal dimension of the root line of Psorbium vulgaris ranged from 1.25787 to 1.42802, and the fractal dimension of the root system was 1.44350 and 1.45141.The root fractal dimension was 1.44350 and 1.45141.The root fractal dimension was 1.25787 to 1.42802, respectively. The root system development of Phaeopodium mongolicum and Cyperus mollissima had typical fractal characteristics. The fractal dimension of root system had a certain influence on the weight and length of root system, and the higher the fractal dimension of root system was. The higher the root length and weight of the plant, the higher the uranium concentration of the root system of the grass growing on the tailings was significantly higher than that of the roots growing in the surrounding environment of the tailings. The results showed that the environment around the tailings reservoir was less affected by the pollution. The overall change trend of uranium concentration in the plants was increasing with the increase of plant root fractal dimension. The higher the plant root fractal dimension, the more complex the root system developed. The higher the uranium content in the plant, the higher the uranium concentration in the roots of the four plants was significantly higher than that in the stems and leaves. Even some plants have hundreds of times more uranium in their roots than in other parts, indicating that uranium is mainly distributed in the roots of plants. The highest concentration of uranium is found in the roots of Cyperus crassifolia, followed by Cortex angustifolia. It is concluded that the sorption of uranium elements by seagrass and Carthopsis chinensis has a certain advantage.
【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X751;X173;Q945

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