Lead accumulation and tolerance of Moso bamboo(Phyllostachys pubescens) seedlings: applications of phytoremediation

植物修复的应用:毛竹苗对铅的积累与耐性研究(英文)

A hydroponics experiment was aimed at identifying the lead（Pb） tolerance and phytoremediation potential of Moso bamboo（Phyllostachys pubescens） seedlings grown under different Pb treatments. Experimental results indicated that at the highest Pb concentration（400 μmol/L）, the growth of bamboo seedlings was inhibited and Pb concentrations in leaves, stems, and roots reached the maximum of 148.8, 482.2, and 4282.8 mg/kg, respectively. Scanning electron microscopy revealed that the excessive Pb caused decreased stomatal opening, formation of abundant inclusions in roots, and just a few inclusions in stems. The ultrastructural analysis using transmission electron microscopy revealed that the addition of excessive Pb caused abnormally shaped chloroplasts, disappearance of endoplasmic reticulum, shrinkage of nucleus and nucleolus, and loss of thylakoid membranes. Although ultrastructural analysis revealed some internal damage, even the plants exposed to 400 μmol/L Pb survived and no visual Pb toxicity symptoms such as necrosis and chlorosis were observed in these plants. Even at the highest Pb treatment, no significant difference was observed for the dry weight of stem compared with controls. It is suggested that use of Moso bamboo as an experimental material provides a new perspective for remediation of heavy metal contaminated soil owing to its high metal tolerance and greater biomass.

目的：探索毛竹在修复铅污染土壤的植物修复潜力。创新点：使用了毛竹作为一种全新的植物修复材料进行研究。得到了毛竹幼苗在铅胁迫下的生长与生理反应情况,不同植物组织对铅的吸收与积累情况,铅胁迫下毛竹幼苗表层与细胞超微结构的特征。方法：根系形态分析（图3）、植物重金属含量分析（表1）、扫描电镜分析（图4）和透射电镜分析（图5）。结论：各组织部位铅浓度的值揭示了,毛竹是一个很好的固定铅污染土壤的植物材料;但是由于毛竹茎的高生物量,也可以作为铅污染土壤的植物修复材料。在0~200μmol/L铅处理下,毛竹的生物量与根系形态没有显著性差异,生长正常未出现中毒症状。通过扫描电镜观察铅胁迫导致叶片的气孔减少,根与茎内含物增多。通过透射电镜观察高浓度的铅胁迫导致部分细胞内部叶绿体变形、内质网消失、细胞核与核仁缩小和类囊体膜消失。尽管超微结构观察到细胞内部的损害,但是未出现视觉的毒性症状。毛竹铅的高耐性与茎的高生物量,提供了毛竹作为材料修复土壤重金属铅更大的可能性。