弯囊苔草对Cd胁迫的响应及其Cd富集能力的研究

通过水培实验,研究了不同Cd2+浓度(0、50μmol/L、100μmol/L、200μmol/L、400μmol/L)下和不同时间内(1d、4d、7d、10d)Cd2+对弯囊苔草生长、生理指标及富集能力的影响。结果表明:(1)株高、最长根长、新增根数、新分蘖数、鲜重和地上与地下部分的干重比均随着Cd2+浓度的提高而逐渐下降。(2)3种抗氧化酶活性均随着Cd2+浓度的增加呈现先上升后下降的趋势。(3)MDA含量、Pro含量和质膜透性均随着Cd2+胁迫浓度的增加和胁迫时间的延长而增加。(4)叶绿素含量在低浓度Cd2+胁迫时增加,高浓度和胁迫时间长时下降。(5)弯囊苔草体内Cd含量随Cd2+浓度的增大而增加,根系对Cd的富集能力明显高于地上部分。根系对Cd的平均滞留率为93.21%,弯囊苔草对Cd的转移系数小于1,表明弯囊苔草根系对Cd有较强的滞留作用和富集能力。

Studies on Responses of Carex dispalata to Cd Stress and Its Accumulation Ability

The effects of Cd2+ on growth characteristics,physiological indices and Cd accumulation ability of Carex dispalata were studied with water culture method.The results showed that:(1) The plant height,length of longest root,number of new root and new tillers,fresh weight and the ratio of shoot to root dry weight were significantly reduced with increasing Cd2+ level.(2) The activities of antioxidant enzymes increased at beginning,and then decreased with increase of Cd2+ concentrations.(3) MDA content,proline content and cell membrane permeability increased with increase of Cd level and time.(4) Chlorophyll content increased under lower Cd2+ concentration,but decreased gradually under higher Cd2+ concentration and longer stress time.(5)The Cd content in Carex dispalata increased with the increase of Cd2+ concentration,and the Cd accumulation ability of root was distinctly higher than that of the above-ground part.The Cd average retention rate in root of Carex dispalata was 93.21% and the biological transfer coefficient to Cd was less than one,which indicated that the root of Carex dispalata has stronger retention action and accumulation ability on Cd.