Tu Cong, Ma Lena Q, Bondada Bhaskar
Soil and Water Science Dep., University of Florida, Gainesville, FL 32611-0290, USA.
J Environ Qual. 2002 Sep-Oct;31(5):1671-5. doi: 10.2134/jeq2002.1671.
The unique property of arsenic hyperaccumulation by the newly discovered Chinese brake (Pteris vittata L.) fern is of great significance in the phytoremediation of arsenic-contaminated soils. The objectives of this study were to (i) examine arsenic accumulation characterized by its distribution pattern in Chinese brake, and (ii) assess the phytoextraction potential of the plant. Young ferns with five or six fronds were transferred to an arsenic-contaminated soil containing 98 mg As kg-1 and grown for 20 wk in a greenhouse. At harvest, the Chinese brake produced a total dry biomass of 18 g plant-1. Arsenic concentration in the fronds was 6000 mg kg-1 dry mass after 8 wk of transplanting, and it increased to 7230 mg kg-1 after 20 wk with a bioconcentration factor (ratio of plant arsenic concentration to water-soluble arsenic in soil) of 1450 and a translocation factor (ratio of arsenic concentration in shoot to that in root) of 24. The arsenic concentrations increased as the fronds aged, with the old fronds accumulating as much as 13,800 mg As kg-1. Most (approximately 90%) of the arsenic taken up by the Chinese brake was transported to the fronds, with the lowest arsenic concentrations in roots. About 26% of the initial soil arsenic was removed by the plant after 20 wk of transplanting. Our data suggest that the arsenic hyperaccumulating property of the Chinese brake could be exploited on a large scale to remediate arsenic contaminated soils.
新发现的蜈蚣草（Pteris vittata L.）蕨类植物具有独特的砷超富集特性，这在砷污染土壤的植物修复中具有重要意义。本研究的目的是：（i）通过蜈蚣草中砷的分布模式来研究其砷积累特征；（ii）评估该植物的植物提取潜力。将具有五六片叶子的幼蕨转移到含98 mg As kg-1的砷污染土壤中，在温室中生长20周。收获时，蜈蚣草的总干生物量为18 g plant-1。移栽8周后，叶片中的砷浓度为6000 mg kg-1干质量，20周后增加到7230 mg kg-1，生物富集系数（植物砷浓度与土壤中水溶性砷的比值）为1450，转运系数（地上部砷浓度与根部砷浓度的比值）为24。随着叶片老化，砷浓度增加，老叶中积累的砷高达13800 mg As kg-1。蜈蚣草吸收的大部分（约90%）砷被转运到叶片中，根部的砷浓度最低。移栽20周后，植物去除了约26%的初始土壤砷。我们的数据表明，蜈蚣草的砷超富集特性可被大规模利用来修复砷污染土壤。
