添加稀土对镉污染土壤上青椒生长与镉吸收分布的影响

Effects of Adding Rare Earths on Growth,Cadmium Absorption and Distribution of Sweet Pepper(Capsicum Annuum var.Annuum) in Cadmium Contaminated Soil

分别以青椒为供试蔬菜、以Cd为供试重金属,采用盆栽试验探索相同规格根际调控基质块中添加不同剂量的碳酸轻稀土对青椒生长、Cd吸收和在器官分配的影响,为今后复合根际修复技术的开展提供理论和实践依据。结果表明:当稀土剂量为40 mg·kg-1时,与不添加稀土的对照相比,极大地促进了青椒苗株高和干重的增加,它们分别提高了21.52%和11.11%。在土壤中含量为5.19 mg·kg-1的Cd胁迫下,保留基质块处理比冲掉块(裸栽)处理的植株地上部干重、生物量、果干重均显著增加,而对根系却没有明显的促进作用。不管基质块中添加不添加稀土,此浓度的Cd胁迫显著抑制了植株根系生长。但适当的稀土添加能够在基质块缓解Cd对青椒毒害的基础上使青椒的生理状况得到进一步改善,而对植株产果没有显著的促进作用。结果还表明:任何剂量的稀土添加对根系Cd含量没有显著降低作用。而当稀土剂量为10 mg·kg-1时,虽然显著促进了茎、叶中Cd的含量,但也显著降低了果实中Cd的含量。由于果实是食用器官,这些结果支撑了稀土添加到基质块作为根际调控方法具有应用价值的重要依据。本试验为以后系统开展复合根际重金属调控研究奠定了基础。

This paper researched the effects of adding different dosage light rare earths （RE） carbonate into same size rhizosphere regulation medium blocks on the growth, Cd absorption and distribution in organs of sweet pepper （Capsicum annuum var. annuum） in Cd contaminated soil to provide theoretical and practical references for exploiting combination remedying tech- niques of rhizosphere. A pot experiment was conduc- ted with sweet pepper as the test vegetable, and Cd as the test heavy metal and added different dosage light RE carbonate into the same size medium blocks to sur- vey the growth, Cd absorption and Cd distribution in different organs of sweet pepper in Cd contaminated soil in this test. When RE dosage was 40 rag·kg- 1, the height and biomass of sweet pepper seedling were greatly improved, and they were increased to 21.52% and 11. 11% respectively compared with out RE adding in block of controlled treatment. The shoot bio- mass, biomass, dry fruit weight of treatments of per- sisting medium block significantly increased than that of washing ment, but out（ bare cultivitation） medium block treat- there were not any effect on roots of the both treatments in the 5.19 mg-kg-1 soil Cd content. No matter adding or no-adding RE, the plant root growth was remarkably confined in this soil Cd con- tent. But proper quantity RE addition could further improve plant physiological condition based on medi- um block alone relieving Cd poison to sweet pepper, but there was not any improvement to plant fruit pro- duction. The result also showed that there was no no- table decrease to root Cd absorption, no matter how much dosage RE was added. When added RE dosage was 10 mg.kg-1, although the Cd content in stems and leaves were notably improved, but significantly decreased in fruit too. These results supported the im- portant application that RE was as a kind of rhizo- sphere regulation additive to medium block. This ex- periment had established a foundation for systematical- ly launching study on heavy metal rhizosphere comple- xing controlling.