水体pH值对喜旱莲子草转运铅离子能力的影响

Effect of Water pH Value on Pb Transport Capacity of Alternanthera philoxeroides

为了研究水体p H值对喜旱莲子草(Alternanthera philoxeroides)转运铅离子(Pb2+)能力的影响,文章通过设计水培实验,调节水体p H值(5.5、6.7、7、8.5)来探讨喜旱莲子草在不同水体介质pH值条件下对低浓度铅(50 mg/L)转运能力的影响。数据表明:随着水体pH值的增加,喜旱莲子草根系的铅含量呈现先降低后增高的趋势,碱性水环境(pH=8.5)中根系铅含量比原始水环境(pH=6.7)根系铅含量高出了163%;叶中铅含量随p H值的增长呈现先增高后降低的趋势,原始环境根系铅含量比碱性环境中根系铅含量高出了251%;茎中铅含量与p H值之间无明显规律,在酸性环境(pH=5.5)中茎中铅含量最多,原始环境中最少;转运系数呈现逐渐降低的趋势。研究结果表明,喜旱莲子草在酸性条件下转运铅离子的能力最强,在碱性条件下铅离子易富集于喜旱莲子草根部,较难向茎、叶部分转移转移,因此,可以通过调节水体pH值提高喜旱莲子草对水体铅污染的修复能力。

In order to study the effect of water pH value on Pb2+transport capacity of Alternanthera philoxeroides,through the design of hydroponic experiment,the pH value of water was adjusted to study the influence of transport capacity of Alternanthera philoxeroides about low concentration lead(50 mg/L)under different pH values(5.5,6.7,7,8.5).The data showed that,with the increase of pH value of water,the lead content of roots of Alternanthera philoxeroides decreased first and then increased.The lead content of roots in alkaline water environment(pH=8.5)was 163%higher than that in the original water environment(pH=6.7).The content of lead in leaves increased first and then decreased with the increase of p H value.The content of lead in roots in the original environment was 251%higher than that in the alkaline environment.There was no obvious rule between the lead content in the stem and the pH value.In the acidic environment(pH=5.5),the lead content in the stem was the most,while the lead content in the original environment was the least.Transfer coefficient shows the tendency of gradually reducing.The results showed that the lead ion transport capacity of Alternanthera philoxeroides was the strongest under acidic conditions,and the lead ion was easy to accumulate in the root of Alternanthera philoxeroides under alkaline conditions,but difficult to transfer to stem and leaf parts.Therefore,Alternanthera philoxeroides’s ability can be improved by adjusting the pH value to repair water lead pollution.