虉草用于干旱地区土壤镉和铜污染修复的潜力

Phytostabilization potential of Phalaris arundinacea L. for cadmium and copper contaminated soil in arid area

利用三因素三水平正交设计,采用盆栽土培法研究了重金属镉(Cd)和铜(Cu)以及水分胁迫对虉草(Phalaris arundinacea L.)生物量、生理指标及积累特性的影响,评估虉草用于干旱地区土壤Cd和Cu污染修复的潜力。结果表明:20%田间持水量胁迫下,虉草失绿、皱缩和萎蔫,生物量最低,MDA和脯氨酸含量显著增加,其余处理组与对照组差异不显著,显示虉草对Cd、Cu和水分胁迫有一定耐性;对虉草生物量和MDA含量影响程度依次为土壤水分含量>Cd浓度>Cu浓度,对脯氨酸含量的影响程度依次为土壤水分含量>Cu浓度>Cd浓度。Cd和Cu在虉草组织中的积累表现为地下部>地上部;虉草Cd富集系数大于1,Cu富集系数基本大于1,Cd富集系数>Cu富集系数,Cd和Cu转移系数均小于1。这表明虉草可用于适度干旱地区Cd和Cu污染土壤的植物固定,通过Cd和Cu富集系数的比较,其更宜用于Cd污染土壤。

A pot experiment was carried out in greenhouse to examine the phytostabilization potential of reed canary grass（Phalaris arundinacea L.） for cadmium（Cd） and copper（Cu） polluted soil in arid regions. An orthogonal experimental design with three factors（i.e., Cd, Cu, and soil moisture） and three levels（i.e., Cd at 50, 110, and 170 mg·kg^-1, Cu at 100, 275, and 450 mg·kg^-1, and soil moisture at 20%, 50%, and 80%） of each factor was employed. Biomass, MDA, and proline content as well as Cd and Cu accumulation of the grass were examined. At soil moisture of 20%, the grass exhibited chlorosis, shrinkage, and wilting, and its biomass was the lowest, but content of MDA and proline was significantly increased. However, no significant differences were found between the other treatments and the control. These three factors influenced biomass and MDA content in order of soil moisture content〉 Cd concentration〉 Cu concentration, while they affected proline content in sequence of soil moisture content〉 Cu concentration〉 Cd concentrations. The accumulation of Cd and Cu in roots was higher than that in shoots. The bioaccumulation factors of both cadmium and copper were greater than 1, with that of cadmium being greater than that of copper. The translocation factors of cadmium and copper were lower than 1. These results suggest that Phalaris arundinacea L. has a certain tolerance to cadmium and copper as well as water stress, and is a promising candidate for phytostabilization of Cd and Cu polluted soil in moderate drought areas.