欢迎访问《生态学杂志》官方网站,今天是 分享到:

生态学杂志

• 研究报告 • 上一篇    下一篇

pH对不同富集能力植物根际土壤溶液中镉形态的影响

廉梅花1,2,孙丽娜2**,胡筱敏1,曾祥峰3,关雪2   

  1. (1东北大学资源与土木工程学院, 沈阳 110004; 2沈阳大学区域污染环境生态修复教育部重点实验室, 沈阳 110044; 3中国科学院沈阳应用生态研究所, 中国科学院污染生态与环境工程重点实验室, 沈阳 110016)
  • 出版日期:2015-01-10 发布日期:2015-01-10

Effect of pH on cadmium speciation in rhizosphere soil solutions of different cadmium accumulating plants.

LIAN Mei-hua1,2, SUN Li-na2**, HU Xiao-min1, ZENG Xiang-feng3, GUAN Xue2   

  1. (1College of Resources and Civil Engineering, Northeast University, Shenyang 110004, China; 2 Key Laboratory of Regional Environment and EcoRemediation, Ministry of Education, Shenyang University, Shenyang 110044, China; 3Key Laboratory of Pollution Ecology and Environment Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China)
  • Online:2015-01-10 Published:2015-01-10

摘要: 为了解不同pH对土壤溶液中Cd形态分布的影响,采用Visual MINTEQ 3.0模型和阳极溶出伏安法(ASV)研究土壤pH分别为4.0、5.5、7.0和8.5时镉超富集植物东南景天和非富集植物垂盆草根际土壤溶液中Cd的形态分布。模型计算结果表明:随着pH的升高,2种植物土壤溶液中Cd2+的比例均逐渐减小,其中东南景天根际土壤溶液中Cd2+占总溶解性Cd的比例为46.1%~3.2%,垂盆草为60.9%~9.9%;当土壤pH≥5.5时,土壤溶液中Cd形态主要以有机络合态(Cd-DOM)为主;2种植物相比,4个pH水平下垂盆草土壤溶液中Cd2+比例均高于东南景天,但东南景天中有机络合态Cd所占比例较大。基于ASV法的测定结果表明:东南景天土壤溶液中电活性Cd占总溶解性Cd的比例从最小(pH 8.5时)的5.5%到最大(pH 4.0时)的79.6%,而垂盆草的变化范围为11.8%~86.7%;电活性Cd的测定结果与Visual MINTEQ 3.0模型计算结果显著相关(R2=0.80),从而互相验证了实验测量和模拟计算的可靠性。

关键词: 林冠垂直结构, 林冠覆盖度, 常绿阔叶林, 物种多样性

Abstract: In order to understand the effects of pH on Cd speciation in soil solution,  anodic stripping voltammetry (ASV) and Visual MINTEQ 3.0 model were developed to characterize the speciation of Cd in rhizosphere soil solutions of Cdhyperaccumulating ecotype (HE, Sedum alfredii Hance) and non-hyperaccumulating ecotype (NHE, Sedum sarmentosum Bunge) under different soil pH conditions (4.0, 5.5, 7.0 and 8.5). The model simulation results demonstrated that the proportions of Cd2+ in soil solutions of both two plants decreased with the increase of pH. Cd2+ fraction in rhizosphere solution varied between 46.1%-3.2% for HE, and 60.9%-9.9% for NHE. Cd-DOM complexes were the dominant Cd speciation when pH≥5.5. Cd2+ fractions in rhizosphere solution were always greater for NHE than for HE, but Cd-DOM complexes were the reverse. In addition, results measured by ASV showed that labile Cd complexes varied from 5.5% (pH 8.5) to 79.6% (pH 4.0) for HE, and between 11.8%-86.7% for NHE. Moreover, the fractions of labile Cd measured by ASV were significantly correlated with those calculated by the model (R2=0.80); the results verified the suitability of both the experimental and model methods.

Key words: species biodiversity, canopy coverage, evergreen broadleaved forest, canopy vertical structure