Lin Lijin, Shi Jun, Liu Qihua, Liao Ming'an, Mei Luoyin
College of Horticulture, Sichuan Agricultural University, Ya'an, Sichuan, 625014, China.
Environ Monit Assess. 2014 Jul;186(7):4051-6. doi: 10.1007/s10661-014-3679-8. Epub 2014 Feb 12.
In a preliminary study, we found that the cadmium (Cd) concentrations in shoots of the winter farmland weeds Cardamine hirsuta Linn. and Gnaphalium affine D. Don exceeded the critical value of a Cd-hyperaccumulator (100 mg kg(-1)), indicating that these two farmland weeds might be Cd-hyperaccumulators. In this study, we grew these species in soil containing various concentrations of Cd to further evaluate their Cd accumulation characteristics. The biomasses of C. hirsuta and G. affine decreased with increasing Cd concentrations in the soil, while the root/shoot ratio and the Cd concentrations in shoot tissues increased. The Cd concentrations in shoots of C. hirsuta and G. affine reached 121.96 and 143.91 mg kg(-1), respectively, at the soil Cd concentration of 50 mg kg(-1). Both of these concentrations exceeded the critical value of a Cd-hyperaccumulator (100 mg kg(-1)). The shoot bioconcentration factors of C. hirsuta and G. affine were greater than 1. The translocation factor of C. hirsuta was less than 1 and that of G. affine was greater than 1. These findings indicated that C. hirsuta is a Cd-accumulator and G. affine is Cd-hyperaccumulator. Both plants are distributed widely in the field, and they could be used to remediate Cd-contaminated farmland soil in winter.
在一项初步研究中，我们发现冬季农田杂草碎米荠（Cardamine hirsuta Linn.）和鼠麴草（Gnaphalium affine D. Don）地上部分的镉（Cd）浓度超过了镉超富集植物的临界值（100 mg kg⁻¹），这表明这两种农田杂草可能是镉超富集植物。在本研究中，我们将这些物种种植在含有不同浓度镉的土壤中，以进一步评估它们的镉积累特性。随着土壤中镉浓度的增加，碎米荠和鼠麴草的生物量下降，而根冠比和地上组织中的镉浓度增加。在土壤镉浓度为50 mg kg⁻¹时,碎米荠和鼠麴草地上部分的镉浓度分别达到121.96和143.91 mg kg⁻¹。这两个浓度均超过了镉超富集植物 的临界值（100 mg kg⁻¹）。碎米荠和鼠麴草的地上生物富集系数均大于1。碎米荠的转运系数小于1，而鼠麴草的转运系数大于1。这些结果表明，碎米荠是一种镉积累植物，而鼠麴草是镉超富集植物。这两种植物在田间分布广泛，可用于冬季修复镉污染的农田土壤。
