碎米荠对硒、镉超富集特性研究

超富集植物在营养元素生物强化及重金属污染植物修复技术领域有重大应用前景。通过野外调查和栽培实验,研究了碎米荠植物对硒镉的吸收富集特征。研究表明:野生碎米荠中Se含量达数百mg/kg,叶片中Se最高含量为1 365 mg/kg。地上部Se的生物富集系数在2.8~43.8的范围内,大部分超过10;生物转移系数在0.46~1.88之间,大部分大于1。地上部Cd含量都超过了100 mg/kg,叶中的Cd含量大部分在400~800 mg/kg之间。富集系数都大于1,且农田及小溪流域植株地上部Cd的生物富集系数高达几十甚至上百,Cd的生物转移系数大部分超过1。露天栽培条件下,碎米荠中的硒镉含量随盆栽土壤中硒镉浓度的上升呈现出先增加后降低的特征,当Se含量为50 mg/kg时植物中的Se含量最高,此时地上部Se含量为995 mg/kg,地下部Se含量1 100 mg/kg。当Cd浓度为80 mg/kg时,植株当中Cd含量最高,地上部和地下部中的Cd含量分别高达550 mg/kg、337 mg/kg。研究认为湖北渔塘坝发育的碎米荠植物是硒镉多元素超富集植物,在硒镉生态环境污染修复方面具有重大应用前景。

A Study on Hyperaccumulation of Se and Cd in Cardamine violifolia

Hyperaccumulator has considerable application potential for nutrient elements biofortification and phytoremediation of heavy metals contamination. Through field investigation and cultivation experiment, the study discussed the intake and accumulation of Se and Cd in Cardamine violifolia. Results show that Se contents in wild Cardamine violifolia are up to hundreds of mg/kg, and the highest Se content in leaves is 1 365 mg/kg. The bioconcentration factor of Se in the overground part is in the range of 2.8-43.8 and most of them are higher than 10; the transfer coefficient is in the range of 0.46-1.88 and most of them are higher than 1. The Cd contents in the overground part of the plant are higher than 100 mg/kg, and most of leaf-Cd contents are between 400 mg/kg and 800 mg/kg. The concentration factor is higher than 1, and bioconcentration factors of Cd in shoots or leaves from farmland and stream area are higher with dozens or over one hundred. Almost all of the biological transfer coefficient of Cd in leaves and stems are higher than 1. Under pot cultivation condition, Se or Cd contents in the plant increase significantly with its increasing gradient of soil, and Se content in the plant is the highest at Se gradient of 50 mg/kg, being 995 mg/kg and 1100 mg/kg in shoot and root, respectively; Cd content is the highest at Cd gradient of 80 mg/kg, being 550 mg/kg and 337 mg/kg in shoot and root, respectively. Our research suggests that Cardamine violifolia is a Se/Cd multi-element hyperaccumulator, moreover, it potentially has important application prospect in ecological remediation of Se and Cd contamination.