黑麦草幼苗对镉耐性能力及吸收积累和细胞分布特点研究

Characteristics of Cadmium Tolerance,Accumulation and Cellular Distribution in Lolium perenne Seedlings

通过盆栽试验研究了镉(Cd)胁迫下黑麦草(LoliumperenneL.)幼苗的耐性能力(包括生长反应和生理生化特性)以及对Cd的吸收、积累、分布特征。结果表明,当Cd浓度为10mg.kg-1时,黑麦草的生长和发育没有受到明显抑制(P>0.05),当Cd浓度为20、60、100mg.kg-1时,黑麦草生物量、叶绿素含量、根系活性都显著降低(P<0.05);超氧阴离子(O2-.)、MDA含量显著增加(P<0.05);SOD、POD活性先增加后降低。黑麦草体内Cd积累量随着Cd浓度增加而显著增加(P<0.05);Cd在亚细胞内积累量:F1(细胞壁)>F3(可溶部分)>F2(细胞器)。黑麦草在Cd浓度为10、20mg.kg-1时,富集系数>1.0,对Cd有较强的富集能力,转移系数<1,富集的Cd主要累积在根部,表明黑麦草能够有效富集土壤中的Cd,且富集的Cd主要积累在根部。

To study the characteristics of cadmium（Cd）tolerance,accumulation and cellular distribution in Lolium perenne,seedlings were grown for 50 days in soils treated with 0,10,20,60 and 100 mg Cd.kg-1 soil,respectively,in a greenhouse experiment.Concentrations of chlorophylls a and b in leaves of Lolium perenne were similar between 10 mg Cd.kg-1 soil and 0 mg Cd.kg-1.Concentrations of chlorophyll a and total chlorophyll in leaves of Lolium perenne exposed to more than 20 mg Cd.kg-1 soil markedly decreased in comparison with those in seedlings exposed to 0 mg Cd.kg-1 soil.The root vigor of Lolium perenne seedlings exposed to 100 mg Cd.kg-1 soil significantly declined in comparison with that of roots exposed to 0 mg Cd.kg-1 soil.Concentrations of oxygen anion pronouncedly increased in seedlings exposed to more than 20 mg Cd.kg-1 soil compared with that in seedlings grown under 0 mg Cd.kg-1 soil.Concentrations of malonaldehyde（MDA）were significantly elevated in Lolium perenne seedlings exposed to more than 20 mg Cd.kg-1 soil compared to that in seedlings exposed to 0 mg Cd.kg-1 soil.The enzyme activities of SOD and POD decreased by 14.6% and 23.9 %,respectively,in seedlings exposed to 100 mg Cd.kg-1 soil in comparison with those in seedlings exposed to 0 mg Cd.kg-1 soil.Biomass markedly decreased in seedlings exposed to more than 20 mg Cd.kg-1 soil compared to that in seedlings grown under 0 mg Cd.kg-1 soil.Cadmium accumulation significantly increased in Lolium perenne seedling along with elevation of cadmium concentrations in soils.Cadmium concentration in cell walls was higher than that in soluble extract in which it was higher than that in cellular organelles.The translocation factor for cadmium was more than 1 when Lolium perenne seedlings were grown under 10 mg Cd.kg-1 soil.These data indicate that Lolium perenne seedlings are tolerant to cadmium and this grass is promising for phyto-remediation in cadmium-contaminated farm land.