Saygideger Saadet, Dogan Muhittin
Department of Biology, Faculty of Arts and Sciences, University of Gaziantep, Gaziantep, Turkey.
J Environ Biol. 2005 Oct;26(4):753-9.
In the present study, effects of pH (5.0, 7.0 and 9.0) and lead (1, 5, 10, 25, 50 and 100 microg mL(-1)) were investigated on uptake of lead, content of chlorophyll and nitrogen in Nasturtium officinale and Mentha aquatica. Total chlorophyll and nitrogen contents were adversely affected from Pb2+ concentrations dose dependently at each pH. The macrophytes were adversely affected by pH 5.0 or more than 9.0. After 12-days Pb2+ treatment, results showed that lead accumulation of macrophyte tissues was variable. According to the parts of the macrophytes, Pb2+ amounts were generally found at all tested pH levels and the metal concentrations for M. aquatica in the following order: root > stem > leaf and for N. officinale root > leaf > stem. Pb2+ concentrations in plant tissues (root, stem, leaf) in relation to pH were generally found for both macrophytes in following order: 7.0 > 9.0 > 5.0. Despite of the fact that high Pb2+ accumulation was observed in root tissues of the macrophytes, low metal accumulation was measured in the above-ground parts indicating low root-leaf translocation. The study indicated that uptake rate of Pb2+ and its toxicity on Chlorophyll and nitrogen contents in the macrophytes were dependent upon pH value of solutions.
在本研究中，研究了pH值（5.0、7.0和9.0）和铅（1、5、10、25、50和100微克/毫升）对豆瓣菜和水生薄荷中铅的吸收、叶绿素含量和氮含量的影响。在每个pH值下，总叶绿素和氮含量均受到Pb2+浓度的剂量依赖性负面影响。pH值为5.0或高于9.0时，大型植物受到负面影响。经过12天的Pb2+处理后，结果表明大型植物组织中的铅积累情况各不相同。根据大型植物的部位，在所有测试的pH值水平下均发现了Pb2+含量，水生薄荷中金属浓度的顺序为：根＞茎＞叶，豆瓣菜为根＞叶＞茎。两种大型植物的植物组织（根、茎、叶）中Pb2+浓度与pH值的关系通常如下：7.0＞9.0＞5.0。尽管在大型植物的根组织中观察到高Pb2+积累，但在地上部分测得的金属积累量较低，表明根-叶转运率较低。该研究表明，大型植物中Pb2+的吸收速率及其对叶绿素和氮含量的毒性取决于溶液的pH值。
