类芦对铅镉的吸收动力特性及亚细胞分布规律研究

以南方水土保持植物类芦为研究对象,采用营养液培养的方法,以Pb、Cd为目标污染物,设置不同的胁迫浓度和时间,胁迫后测定类芦体内重金属的含量和亚细胞分布。结果分析发现,类芦体内重金属含量与浓度和时间有显著的关系,可利用Freundlich方程和Michaelis-Menten方程进行拟合,R~20.95,相关性强。通过拟合发现,重金属主要分布在根部,类芦对Pb的吸收能力更强(最高含量达到4 687.87 mg·kg~(-1)),但是对Cd的吸收速率增长更为明显,即类芦在吸收Cd方面有一定的潜力。就亚细胞分布而言,两种重金属均主要分布在细胞壁和可溶组分中,不同浓度和时间处理下,两个组分中的重金属含量共占总量的60%以上。由此说明,类芦对Pb的吸收能力更强,同时,类芦通过改变重金属的亚细胞分布来降低重金属的毒害作用,维持自身的稳态。

Uptake kinetic characteristics and subcellular distribution of Pb2+ and Cd2+ in Neyraudia reynaudiana

Neyraudia reynaudiana is a soil-conservating plant and can grow well in heavy metal polluted soils. Here a solution culture experiment was conducted to examine uptake and subcellular distrubution of Pb and Cd in the plant under different metal levels and stress times. Results showed that the uptake of Pb and Cd by N. reynaudiana increased with heavy metal concentrations and stress time. Freundlich and Michaelis-Menten equations fit the data very well, R²>0.95. It was also revealed that heavy metals were mainly distributed in the roots. Neyraudia reynaudiana had greater absorption ability for Pb(the highest content reached to 4 687.87 mg·kg^-1), but higher absorption rate for Cd. For subcellular distribution, Pb and Cd were mainly distributed in the cell walls and soluble constituents. Under different concentrations and stress times of Pb and Cd, the Pb/Cd content in cell wall and soluble constituent subcellular components accounted for over 60% of the total. Therefore, N. reynaudiana has stronger absorption ability of Pb, and it could change the subcellular distribution of heavy metals to reduce the toxicity of heavy metals for maintaining its steady state. This study provides theoretical support for screening phytoremediation materials.