植物根系多环芳烃的短距离和长距离运输过程研究

发布时间：2018-10-08 17:23

【摘要】：由于多环芳烃在环境中的高残留、可在植物体内积累并能通过食物链进入人体,因此研究者对多环芳烃在土壤-植物系统中的迁移过程给予了很大的关注。植物吸收运输多环芳烃的过程与机制研究对于农产品的安全生产和污染土壤的植物修复至关重要,然而迄今尚未见有关于多环芳烃在植物根系内的短距离运输和由根部向地上部的长距离运输过程的报道。为此,本文通过水培实验,对植物根系质外体溶液的提取方法进行了探索,对植物根系质外体和共质体多环芳烃吸收特征差异进行了分析,同时研究了植物根系吸收多环芳烃后茎部伤流液成分的变化,最后探讨了植物根系质外体和共质体多环芳烃吸收运移的影响因素。论文主要结论如下:植物根系质外体溶液的提取方法研究结果表明,小麦根系质外体菲提取量随真空度、真空时间、离心力与离心时间的增加而增大;在一定范围内,小麦根系质外体内六磷酸葡萄糖脱氢酶的活性随各因素的增加而升高。依据质外体溶液受原生质污染程度小于1%且尽量提取完全的原则下,真空渗透离心提取法的最佳真空度为70 kPa,最佳真空时间为10 min,最佳离心速率为3068 r·min-1,最佳离心时间为15 min。在一定的时间范围内,不同温度处理小麦根系质外体和共质体菲吸收量随提取时间的延长而增加,随营养液中菲的浓度的增大而增加。在不同温度处理中,35℃处理小麦根系质外体和共质体菲吸收量最大。在相同温度条件下,小麦根系质外体与共质体对菲的吸收存在显著性差异,共质体对菲的吸收量高于质外体部分。由小麦根系质外体和共质体菲吸收的动力学和热力学可知,温度越高,反应速率常数越大,小麦根系质外体和共质体菲吸收的活化能都为正值,且共质体活化能小于质外体,因此共质体菲吸收易于质外体。伤流液组分分析表明,玉米伤流液中菲高于小麦伤流液,且存在显著性差异CP0.05)。菲处理降低了玉米和小麦植株的伤流液强度,玉米和小麦菲处理后伤流液中有机物质可溶性蛋白含量明显升高(P0.05),玉米甲酸增加显著,小麦甲酸增加不显著,但铵态氮、钾、有效磷及pH显著下降(P0.05)。由此推测,多环芳烃在植物体内的长距离运输与可溶性蛋白关系密切,并且对植物营养物质的运输有抑制作用。植物根系质外体和共质体多环芳烃吸收的影响因素研究表明,黑暗与根系地上部剪切处理能够降低小麦根系质外体的菲吸收。25℃处理小麦根系共质体的菲吸收显著高于4 ℃处理,抑制剂2,4-DNP和钒酸钠抑制了小麦根系共质体的菲吸收。
[Abstract]:Due to the high residue of PAHs in the environment, PAHs can accumulate in plants and enter the human body through the food chain. Therefore, researchers have paid great attention to the migration of PAHs in soil-plant systems. Studies on the processes and mechanisms of plant uptake and transport of polycyclic aromatic hydrocarbons (PAHs) are essential for the safe production of agricultural products and the phytoremediation of contaminated soils. However, there are no reports on the short distance transport of PAHs in plant roots and the long distance transport from root to ground. In this paper, the extraction method of extracellular solution from plant root system was explored by hydroponic experiment, and the differences of the absorption characteristics of polycyclic aromatic hydrocarbons (PAHs) between the plant root system and the plant root system were analyzed. At the same time, the changes of the components of the stem effluents after the plant roots absorbed polycyclic aromatic hydrocarbons (PAHs) were studied. Finally, the factors affecting the absorption and migration of PAHs in the plant roots were discussed. The main conclusions of this paper are as follows: the results of extraction method of plant root exophyte showed that the amount of phenanthrene extracted from wheat root system increased with the increase of vacuum, vacuum time, centrifugal force and centrifugal time, and within a certain range, the extraction amount of phenanthrene from wheat root system increased with the increase of vacuum, vacuum time, centrifugal force and centrifugal time. The activity of glucose-hexaphosphate dehydrogenase in wheat roots increased with the increase of various factors. According to the principle that the degree of protoplast contamination is less than 1% and the extraction is as complete as possible, the optimum vacuum degree is 70 kPa, the optimum vacuum time is 10 min, the optimal centrifugation rate is 3068 r min-1, the optimum centrifugal time is 15 min.. In a certain time range, the phenanthrene absorption of wheat root and synplast increased with the increase of extraction time and the concentration of phenanthrene in the nutrient solution. The phenanthrene absorption of wheat root at 35 鈩，

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