镧胁迫对胡枝子种子萌发及幼苗生长特性的影响

Seed Germination and Seedling Growth Characteristics of Lespedeza bicolor under Lanthanum Stress

研究不同浓度稀土元素镧(La)对胡枝子(Lespedeza bicolor)种子萌发及幼苗生长的影响,探索胡枝子对稀土元素镧的耐受程度。采用培养皿滤纸发芽法,分别用不同浓度La^(3+)(0,50,100,200,300,500 mg/L)溶液处理胡枝子种子,测定种子萌发相关指数、幼苗生长指标、叶绿素含量及过氧化物酶(POD)、丙二醛(MDA)和过氧化氢酶(CAT)等抗氧化系统酶活性。与对照相比,不同浓度La^(3+)对胡枝子种子的发芽及幼苗生长具有“低促高抑”作用。胡枝子在不同浓度La^(3+)处理条件下均较好完成了萌发与幼苗生长,当La^(3+)浓度为500 mg/L时严重抑制生根,出现无根苗,但是抗氧化系统酶活性均达到最大值,表现出对La^(3+)的强耐受性。这些结果表明胡枝子对稀土元素镧具有较高耐受性,可作为稀土污染土壤的植物修复材料,这为研究胡枝子对稀土元素耐受机理奠定基础。

The effects of different concentrations of rare earth element lanthanum(La)on seed germination and seedling growth of Lespedeza bicolor were studied,in order to explore the tolerance and mechanism of Lespedeza bicolor to lanthanum.The germination method of petri dish filter paper was used to treat seeds with different concentrations of La^(3+)(0,50,100,200,300,500 mg/L)solutions.The seed germination index,seedling growth index,chlorophyll content and antioxidant enzyme activities such as peroxidase(POD),malondialdehyde(MDA)and catalase(CAT)were determined.Compared with the control,the seeds germination and seedlings growth under La^(3+)stress had the low-promotion and high-suppression effect.When the La^(3+) concentration was 500 mg/L,the three indexes reached the highest value.Lespedeza bicolor successfully completed germination and seedling growth under different concentrations of La^(3+)When the La^(3+)concentration was 500 mg/L,roots were severely inhibited,resulting in rootless seedlings,but the activity of antioxidant system enzymes reached the maximum,showing strong tolerance to lanthanum.These results indicated that Lespedeza bicolor can be used as a phytoremediation material for rare earth contaminated soil with high tolerance.This lays the foundation for the study of the resistance mechanism of Lespedeza bicolor to rare earth elements.