Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy, University of South China, Henyang, 421001, People's Republic of China.
Hunan Province Key Laboratory of Green Development Technology for Exetremely Low Grade Uranium Resources, University of South China, Henyang, 421001, People's Republic of China.
J Environ Radioact. 2019 Nov;208-209:106036. doi: 10.1016/j.jenvrad.2019.106036. Epub 2019 Sep 4.
In order to develop an artificially constructed plant community plot for the enhanced phytoremediation of uranium contaminated soils, three uranium accumulators including Bamboo-willow (Salix sp.), Paspalum scrobiculatum linn and Macleaya cordata were used to construct four artificial plant community plots, and greenhouse experiments were conducted to investigate the bioaccumulation of uranium by the plants and the organic acid content, enzyme activity, and the change of microbial community structure in their rhizosphere soils. The transfer factor (TF) and the total bioaccumulation amount (TBA) of uranium were used to describe remediation efficiencies in this paper. It was found that their remediation efficiencies were in the order Bamboo-willow (Salix sp.)-Paspalum scrobiculatum linn-Macleaya cordata > Bamboo-willow (Salix sp.)-Macleaya cordata > Paspalum scrobiculatum linn-Macleaya cordata > Bamboo-willow (Salix sp.)-Paspalum scrobiculatum linn. The bioaccumulation amount of uranium by each plant in the Bamboo-willow (Salix sp.)-Paspalum scrobiculatum linn-Macleaya cordata community plot was significantly (P < 0.05) higher than that by its single population, the bioaccumulation amounts of uranium by Bamboo-willow (Salix sp.), Paspalum scrobiculatum linn and Macleaya cordata were 0.29, 0.32 and 2.19 mg/plant, respectively, and they were increased by 31.82%, 77.78% and 146.07%, respectively, and the transfer efficiencies by the plants were increased by 150%, 110% and 52.17%, respectively. The interaction between the plants' roots and the microorganisms in the rhizosphere soil of the Bamboo-willow (Salix sp.)-Paspalum scrobiculatum linn-Macleaya cordata community plot resulted in the high content of organic acids such as oxalic acid in the rhizosphere soil of the plant community plot, which was significantly (P < 0.05) higher than that of its single population. The chelation of the organic acids with uranium led to an increase in the proportion of exchangeable uranium in soil solution. In addition, Burkholderia, which is an iron-producing carrier bacterium and can increase the uptake and accumulation of uranium by plants, and Leptolyngbya, which is a plant growth promoting rhizobacteria and can increase the biomass of plants, emerged in the rhizosphere soil of the plant community plot. These may be the mechanisms by which the phytoremediation of the uranium contaminated soils was enhanced by the plant community plot.
为了开发一种用于增强铀污染土壤植物修复的人工构建植物群落小区，选用 3 种铀超积累植物包括柳树（Salix sp.）、雀稗（Paspalum scrobiculatum linn）和博落回（Macleaya cordata）构建了 4 个人工植物群落小区，并通过温室实验研究了植物对铀的生物积累以及其根际土壤中有机酸含量、酶活性和微生物群落结构的变化。本文用转移因子（TF）和总生物积累量（TBA）来描述修复效率。结果表明，其修复效率的顺序为柳树（Salix sp.）-雀稗（Paspalum scrobiculatum linn）-博落回＞柳树（Salix sp.）-博落回＞雀稗（Paspalum scrobiculatum linn）-博落回＞柳树（Salix sp.）-雀稗（Paspalum scrobiculatum linn）。柳树（Salix sp.）-雀稗（Paspalum scrobiculatum linn）-博落回群落小区中每种植物对铀的生物积累量均显著（P<0.05）高于其单种群，柳树（Salix sp.）、雀稗（Paspalum scrobiculatum linn）和博落回对铀的生物积累量分别为 0.29、0.32 和 2.19mg/株，分别增加了 31.82%、77.78%和 146.07%，植物的转移效率分别增加了 150%、110%和 52.17%。柳树（Salix sp.）-雀稗（Paspalum scrobiculatum linn）-博落回群落小区中植物根系与根际土壤微生物的相互作用导致根际土壤中有机酸（如草酸）含量较高，显著（P<0.05）高于单种群。有机酸与铀的螯合作用导致土壤溶液中可交换态铀的比例增加。此外，博来氏菌（Burkholderia）作为一种产铁载体菌，可增加植物对铀的吸收和积累，以及鞘氨醇单胞菌（Leptolyngbya）作为一种促进植物生长的根际细菌，可增加植物的生物量，在植物群落小区的根际土壤中出现。这些可能是植物群落小区增强铀污染土壤植物修复的机制。
