苎麻对镉胁迫的响应及其对其它重金属吸收能力的研究

通过田间微区模拟试验，以中苎1号、湘苎2号和湘苎3号为材料，研究苎麻对镉（Cd）胁迫的响应及其吸收铅（Pb）、铜（Cu）、锌（Zn）和镍（Ni）的能力。结果表明：供试3个品种均有较强的Cd耐受能力（耐受Cd的阈值为11．7mg·kg^-1），其中湘苎3号耐受Cd的能力最强，在Cd添加量为0～100mg·kg^-1时，其有效株为15．7—29．0株/m^2、生物量为0．67～1．01kg·m^-2、原麻产量为55．4—76．8g·m^-2，显著高于其它2个品种；随着土壤Cd添加量的增大，3个品种地上部的Cd含量及其累积量均显著增加，最高可迭61．5mg·kg^-1与49．6mg·m^-2，表明苎麻对cd具有较强的富集能力，但并未达到Cd的超富集植物的水平；Cd胁迫条件下，3个品种对Pb、Cu、Zn、Ni等重金属的吸收因元素种类的不同而异，中苎1号对Pb、Ni吸收呈现出随土壤Cd添加量增大而增加的趋势，湘苎3号对Zn、Ni吸收则呈现出随土壤Cd添加量增大而减少的趋势，但土壤Cd添加量对3个品种吸收Cu的影响并不明显。同时，苎麻还具有较好的经济效益且不进入食物链，是一种理想的修复与利用重金属污染土壤的备选植物，但镉胁迫对苎麻吸收Pb、Cu、Zn、Ni等重金属的影响机制尚需进一步研究。

Response of Ramie Growth to Cd Stress and Its Uptake of Heavey Metals

In order to investigate the tolerance of ramie （ 3 cuhivars including Zhongzhu No. 1, Xiangzhu No. 2 and Xiangzhu No. 3 ） to Cd and its uptake of Pb, Cu, Zn and Ni, a field micro - plot ex- periment was conducted. The results indicated that the three tested ramie cultivars had a certain extent of tolerance to soil Cd （threshold biomass and raw fibre yield of value of soil Cd concentration is 11.7mg · kg^-1） . The effective tillers, Xiangzhu No. 3 were 15.7 - 29.0 no. m^-2, 0. 67 - 1.01 kg · m^-2 and 55.4 - 76.8 g · m^-2, respectively, which were significantly larger than the other two cuhivars under soil Cd addition at 0 to 100 mg ·kg^-1. This indicated that Xiangzhu No. 3 had a higher tolerance to soil Cd contamination. With the increase of soil Cd, Cd content in the aboveground parts of the three ramie eultivars increased significantly. In the present study, the highest concentration and accumulation of Cd in the aboveground parts of ramie were 61.5 mg · kg^-1 and 49.6 mg· m^-2, which indicated that the ramie had a strong accumulation ability of Cd. However, ramie was not a Cd - hyperaecumulator. The effects of Cd on the uptake of Pb, Cu, Zn, and Ni varied largely among the ramie varieties and heavy metals. Cadmium addition increase induced the increase of Pb and Ni absorption in Zhongzhu No. 1, and decreased the uptake of Zn and Ni in Xiangzhu No. 3. Moreover, ramie is an economical crop and doesn＇ t enter in the food chain. In conclusion, ramie could be a valid alternative for heavy metal contaminated soil remediation, and the mechanism of Cd affecting the uptake of other heavy metals by ramie needs further study.