重金属和菌肥对植物修复铀污染土壤的影响

发布时间：2018-01-09 09:14

本文关键词：重金属和菌肥对植物修复铀污染土壤的影响　出处：《西南科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：本研究以菊苣(Cichorium intybus L.)为修复植物,采用盆栽试验研究铀和重金属在植物修复过程中的相互影响以及微生物菌肥在修复过程中的作用,为植物-微生物联合修复技术的应用和推广提供依据。土壤处理分两次进行:(1)铀处理浓度分别为:0、50、100、150 mg·kg-1干土,每个铀浓度下面分别设计镉、铅、汞、镍、铬5种重金属处理,浓度分别为0、低浓度(1倍本底浓度)和高浓度(5倍本底浓度),以铀和重金属的0处理为对照。(2)在试验(1)结束后向铀、镍、镉单独处理及混合污染的土壤中施加200倍EM菌液。两次试验中播种、生长期间的管理及测定的各项指标相同。试验结果表明:(1)Cd和铀共存对菊苣发芽有一定的伤害,并且Cd加强了铀对菊苣生长的抑制作用。在高浓度铀污染的土壤中,Pb或Hg或Ni的存在加强了铀对菊苣实生苗生长的抑制作用,却缓解了铀对再生苗植株长高的影响,同时又与铀共同促进了再生苗生物量的增加。含有Cr的处理中植株大部分死亡,Cr对菊苣的毒性最强。Pb或Hg或N i都可以在一定程度上缓解高浓度铀对菊苣的伤害,主要表现为当U=150 mg·kg-1时,铀与某种重金属的联合污染与单独铀污染相比净光合速率增加,Fo下降,Fv/Fm和Fm升高。(2)在高浓度铀污染的土壤中,适当浓度的Cd或Pb或Hg或Ni离子有助于菊苣对铀的吸收和积累,其中Pb的促进作用最大,Ni的促进作用最小,同时Cd有利于铀从根部向茎叶转移。在Cd或Pb或Ni污染的土壤中,铀的存在抑制菊苣对这三种重金属的吸收,同时高浓度铀(150 mg·kg-1)抑制Cd从根部向茎叶转移,却增加Ni或Pb的转移。(3)EM菌肥加重了铀单独胁迫及高浓度铀镉共同胁迫对菊苣的伤害,导致菊苣叶片的净光合速率(Pn)和Fv/Fm降低,却能提高POD和SOD的活性减轻对细胞膜的损伤。另外,EM菌肥可以提高菊苣对铀镍共同胁迫的耐受性。(4)在低浓度铀单独污染土壤中,EM菌肥不利于菊苣对铀的吸收,但是提高了铀从菊苣根部向茎叶的转移效率。在高浓度铀污染土壤中,高浓度镍或镉存在时,EM菌肥不利于菊苣对铀的吸收和转移,低浓度镍存在时有利于菊苣对铀的吸收。在镍单独胁迫及高浓度铀镍共同胁迫下,EM菌肥不利于菊苣对镍的吸收,却有助于镍从根部向茎叶转移。在高浓度镉与高浓度铀共同污染土壤中,菌肥有助于菊苣对镉的吸收。因此,在高浓度铀污染土壤中,一定浓度重金属的存在减轻了铀对植物的胁迫;在中低浓度铀污染土壤中,重金属抑制植物对铀的积累;在高浓度铀污染土壤中,重金属促进植物对铀的积累;菌肥不利于植物对铀的吸收,但可提高根系铀向茎叶的转移效率。
[Abstract]:In this study, Cichorium intybus L.) was used as restoration plant. Pot experiments were conducted to study the interaction between uranium and heavy metals in the process of phytoremediation and the role of microbial microbial fertilizer in the process of remediation. It provides the basis for the application and popularization of the plant-microorganism combined remediation technology. The soil treatment is divided into two stages. The concentration of uranium treatment is 150 mg 路kg-1 dry soil, respectively. Cadmium, lead, mercury, nickel and chromium were designed under each uranium concentration with concentrations of 0, 1 times background concentration (low concentration) and 5 times background concentration (high concentration). The soil contaminated with uranium, nickel and cadmium was treated separately and mixed with EM bacteria solution of 200 times after the end of test No. 1. The seeds were seeded in two experiments. The results showed that the coexistence of CD and uranium in the growth period caused some damage to the germination of chicory. CD enhanced the inhibitory effect of uranium on the growth of chicory. The presence of Pb or Hg or Ni in the soil contaminated with high concentration of uranium enhanced the inhibitory effect of uranium on the growth of chicory seedlings. However, the effect of uranium on the plant height of regenerated seedlings was alleviated, and at the same time, the biomass of regenerated seedlings was increased together with uranium. Most of the plants died in the treatment containing Cr. Cr was the most toxic to chicory. Pb or Hg or Ni could alleviate the damage of high concentration uranium on chicory to a certain extent. The main effect of Cr on chicory was that when UCU was 150mg 路kg-1. The combined contamination of uranium with some heavy metals increased the net photosynthetic rate (Fo) decreased FV / Fm and Fm increased in the soil contaminated with high concentration of uranium. The proper concentration of CD or Pb or Hg or Ni ions contributed to the absorption and accumulation of uranium in chicory. In the soil contaminated by CD or Pb or Ni, the presence of uranium inhibited the uptake of these three heavy metals by chicory. At the same time, high concentration of uranium (150 mg 路kg -1) inhibited the transfer of CD from roots to stems and leaves. However, increasing the transfer of Ni or Pb, the EM fertilizer increased the damage to chicory under the stress of uranium alone and high concentration of uranium and cadmium, which resulted in the decrease of net photosynthetic rate (PN) and Fv/Fm in leaves of chicory. But it could increase the activity of POD and SOD and reduce the damage to cell membrane. In addition, EM fertilizer could improve the tolerance of chicory to U-Ni co-stress. EM fertilizer was not conducive to the absorption of uranium from chicory, but increased the transfer efficiency of uranium from the root to stem and leaf of chicory. In the soil contaminated with high concentration of uranium, high concentration of nickel or cadmium existed. Em fertilizer was not conducive to the absorption and transfer of uranium in chicory, and the low concentration of nickel was beneficial to the absorption of uranium in chicory, but under the stress of nickel alone and high concentration of uranium and nickel, EM fertilizer was not conducive to the absorption of nickel in chicory. But it helps to transfer nickel from roots to stems and leaves. In the soil contaminated by high concentration of cadmium and high concentration of uranium, bacterial fertilizer is helpful to the absorption of cadmium in chicory. Therefore, in the soil contaminated with high concentration of uranium. The presence of certain concentrations of heavy metals alleviated the stress of uranium on plants. Heavy metals inhibit the accumulation of uranium by plants in the soil contaminated with low and medium concentrations of uranium. In the soil contaminated with high concentration of uranium, heavy metals promote the accumulation of uranium in plants. Bacterial fertilizer is not conducive to the absorption of uranium by plants, but it can improve the efficiency of uranium transfer from roots to stems and leaves.
【学位授予单位】：西南科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X173;X53

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