State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, China.
J Appl Microbiol. 2011 Nov;111(5):1065-74. doi: 10.1111/j.1365-2672.2011.05142.x. Epub 2011 Sep 29.
Bioremediation of highly arsenic (As)-contaminated soil is difficult because As is very toxic for plants and micro-organisms. The aim of this study was to investigate soil arsenic removal effects using poplar in combination with the inoculation of a plant growth-promoting rhizobacterium (PGPR).
A rhizobacterium D14 was isolated and identified within Agrobacterium radiobacter. This strain was highly resistant to arsenic and produced indole acetic acid and siderophore. Greenhouse pot bioremediation experiments were performed for 5 months using poplar (Populus deltoides LH05-17) grown on As-amended soils, inoculated with strain D14. The results showed that P. deltoides was an efficient arsenic accumulator; however, high As concentrations (150 and 300 mg kg(-1)) inhibited its growth. With the bacterial inoculation, in the 300 mg kg(-1) As-amended soils, 54% As in the soil was removed, which was higher than the uninoculated treatments (43%), and As concentrations in roots, stems and leaves were significantly increased by 229, 113 and 291%, respectively. In addition, the As translocation ratio [(stems + leaves)/roots = 0·8] was significantly higher than the uninoculated treatments (0·5). About 45% As was translocated from roots to the above-ground tissues. The plant height and dry weight of roots, stems and leaves were all enhanced; the contents of chlorophyll and soluble sugar, and the activities of superoxide dismutase and catalase were all increased; and the content of a toxic compound malondialdehyde was decreased.
The results indicated that the inoculation of strain D14 could contribute to the increase in the As tolerance of P. deltoides, promotion of the growth, increase in the uptake efficiency and enhancement of As translocation.
The use of P. deltoides in combination with the inoculation of strain D14 provides a potential application for efficient soil arsenic bioremediation.
生物修复高度砷（As）污染土壤是困难的，因为 As 对植物和微生物非常有毒。本研究的目的是研究杨树与接种植物生长促进根际细菌（PGPR）结合对土壤砷去除的影响。
从根瘤菌属（Agrobacterium radiobacter）中分离并鉴定出一株 rhizobacterium D14。该菌株对砷具有高度抗性，并产生吲哚乙酸和铁载体。在温室盆栽生物修复实验中，使用生长在添加砷的土壤上的杨树（Populus deltoides LH05-17），接种菌株 D14，进行了 5 个月的实验。结果表明，P. deltoides 是一种有效的砷积累植物；然而，高砷浓度（150 和 300 mg kg(-1)）抑制其生长。通过细菌接种，在 300 mg kg(-1) 的 As 污染土壤中，土壤中 54%的 As 被去除，高于未接种处理（43%），并且根、茎和叶中的 As 浓度分别显著增加了 229%、113%和 291%。此外，As 转运率[(茎+叶)/根=0.8]明显高于未接种处理（0.5）。约 45%的 As 从根部转运到地上组织。植物高度和根、茎、叶的干重均增加；叶绿素和可溶性糖的含量增加，超氧化物歧化酶和过氧化氢酶的活性增加，有毒化合物丙二醛的含量降低。
结果表明，接种菌株 D14 可以提高 P. deltoides 的砷耐受性，促进其生长，提高其吸收效率并增强砷的转运。
利用 P. deltoides 与菌株 D14 接种相结合，为高效土壤砷生物修复提供了一种潜在的应用。
