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硅对不同品种水稻吸收镉的影响与机制研究

发布时间:2019-01-11 10:45  文章来源:笔耕文化传播
【摘要】:重金属污染土壤的防治是全世界普遍关注的热点、难点问题之一。近几十年来,由于采矿、污灌、三废排放和肥料不合理施用,我国农田土壤镉污染日趋严重。目前,其治理的方法有很多,其中关于硅对作物镉毒害的缓解作用已被国内外学者广泛认同。前人研究使用的含硅物料多为碱性物质,且含有伴随离子,而pH和伴随离子又是影响镉活性的重要因素,那么含硅物料对作物镉毒害的缓解是改变土壤pH和伴随离子引起,还是硅自身的作用就很难确定。因此,本试验在消除pH和伴随离子影响的基础上,采取室内分析和生物试验相结合的手段,研究镉胁迫下施硅对两种水稻逆境和细胞结构、镉吸收与分配、土壤吸附解吸镉的影响,以期明确施硅条件下,镉累积性不同品种水稻对镉的响应以及硅抑制水稻累积镉的机制。研究结论如下:1.硅通过影响抗氧化酶活性和游离脯氨酸含量,缓解了膜脂过氧化作用,在相同条件下,"辽星19"体内膜脂质过氧化程度大于"辽粳9"。加硅使叶片细胞结构趋于完整,叶绿体片层排列逐渐整齐、清晰,嗜锇颗粒逐渐变小、变少;线粒体数目逐渐增多,双层膜解体现象得到缓解。2.硅使镉滞留在水稻根部,减少了向地上部的运输,有效缓解镉对水稻的毒害,增加水稻生物量,提高水稻产量,降低糙米中镉的含量。与单加镉处理相比,施硅显著降低两种水稻稻米中镉含量(P0.01)。在相同条件下,"辽星19"糙米、茎叶转移富集能力大于"辽粳9"。3.硅促进了土壤对镉的吸附,抑制土壤镉的解吸,其效应随着加硅量的增加而增大;硅还可降低土壤中酸可提取态、可还原态镉含量,提高土壤中可氧化态、残渣态镉含量,从而降低了镉的生物有效性。综上所述,硅能有效缓解镉对水稻的毒害,提高水稻产量,降低糙米中镉含量,在施硅量为100、150 mg/kg时,"辽粳9"糙米中镉含量达到国家标准;施硅促进土壤对镉的吸附,加剧解吸的滞后效应,使土壤中的镉向无效形态转化。因此,在镉中、低污染地区,种植镉累积性较低的水稻品种,配合施用硅肥,可以实现镉污染土壤修复和安全利用。
[Abstract]:The prevention and control of heavy metal contaminated soil is one of the hot and difficult problems in the world. In recent decades, because of mining, sewage irrigation, waste discharge and unreasonable application of fertilizer, cadmium pollution of farmland soil in China is becoming more and more serious. At present, there are many ways to control the effects of silicon on crop cadmium toxicity, which has been widely recognized by domestic and foreign scholars. Most of the silicon-containing materials used in previous studies are alkaline materials and accompanied ions, and pH and accompanying ions are important factors affecting cadmium activity, so the mitigation of cadmium toxicity caused by silicon-containing materials is caused by changing soil pH and accompanying ions. The role of silicon itself is hard to determine. Therefore, on the basis of eliminating the effects of pH and accompanying ions, the effects of silicon on the stress, cell structure, absorption and distribution of cadmium in rice under cadmium stress were studied by the combination of laboratory analysis and biological experiments. The effect of soil adsorption and desorption of cadmium in order to clarify the cadmium accumulation of different rice varieties under the condition of silicon application, and the mechanism of silicon inhibiting cadmium accumulation in rice. The conclusions are as follows: 1. Silicon alleviates membrane lipid peroxidation by affecting antioxidant enzyme activity and free proline content. Under the same conditions, the degree of membrane lipid peroxidation in "Liaoxing 19" is greater than that in "Liaojing 9". Adding silicon made the leaf cell structure complete, the chloroplast lamellar arrangement was neat and clear, osmiophilic particles became smaller and less, the number of mitochondria gradually increased, and the phenomenon of double layer membrane disintegration was alleviated. 2. Silicon makes cadmium stay in the root of rice, reduces the transportation to the aboveground, effectively alleviates the toxicity of cadmium to rice, increases the biomass of rice, increases the yield of rice, and reduces the content of cadmium in brown rice. Compared with single cadmium treatment, silicon application significantly decreased the cadmium content in rice (P0.01). Under the same conditions, the enrichment ability of "Liaoxing 19" brown rice was higher than that of "Liaojing 9". Silicon promoted the adsorption of cadmium and inhibited the desorption of cadmium, and the effect increased with the increase of the amount of silicon added. Silicon can also reduce the contents of extractable acid and reductive cadmium in soil and increase the content of oxidizable and residual cadmium in soil, thus reducing the bioavailability of cadmium. To sum up, silicon can effectively alleviate the toxicity of cadmium to rice, increase the yield of rice and reduce the cadmium content in brown rice. When the amount of silicon applied is 100150 mg/kg, the cadmium content in "Liaojing 9" brown rice reaches the national standard. Application of silicon promoted the adsorption of cadmium in soil, aggravated the delayed effect of desorption, and transformed cadmium in soil into invalid form. Therefore, in the middle and low pollution area of cadmium, planting rice varieties with low cadmium accumulation and applying silicon fertilizer can realize the remediation and safe utilization of cadmium contaminated soil.
【学位授予单位】:沈阳农业大学
【学位级别】:硕士
【学位授予年份】:2017
【分类号】:X53;X173


本文编号:2407049


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