The Key Lab of Resource Environment and GIS, College of Resource Environment and Tourism, Capital Normal University, 105 North Road of Xisanhuan, Beijing 100048, China.
Ecotoxicol Environ Saf. 2010 Sep;73(6):1272-8. doi: 10.1016/j.ecoenv.2010.05.016. Epub 2010 Jun 8.
The effects of pH and some cations on the acute toxicity of zinc (Zn) to barley (Hordeum vulgare) root elongation were investigated to aid the development of an appropriate biotic ligand model (BLM). The results showed that Zn toxicity decreased with increased activity of Mg2+, K+ and Ca2+ but not Na+. The effect of pH on Zn toxicity to barley root elongation could be explained by H+ competition with Zn2+ bound to a biotic ligand (BL) at pH<or=6 and by the concomitant toxicity of ZnHCO3+ in solution culture at pH>or=6. Stability constants were obtained for the binding of Zn2+, ZnHCO3+, Mg2+, K+, Ca2+ and H+ with BL: logKZnBL 4.06, logKZnHCO3BL+ 5.15, logKMgBL 3.72, logKKBL 2.62, logKCaBL 1.99 and logKHBL 4.27. On the basis of these estimated parameters, a BLM was successfully developed to predict Zn toxicity to barley root elongation as a function of solution characteristics.
为了帮助开发合适的生物配体模型（BLM），研究了 pH 值和一些阳离子对锌（Zn）对大麦（Hordeum vulgare）根伸长急性毒性的影响。结果表明，随着 Mg2+、K+和 Ca2+活性的增加，Zn 毒性降低，但 Na+则不然。pH 值对 Zn 毒性对大麦根伸长的影响可以用 H+与与生物配体（BL）结合的 Zn2+竞争来解释，也可以用 pH≥6 时溶液培养中 ZnHCO3+的伴随毒性来解释。获得了 Zn2+、ZnHCO3+、Mg2+、K+、Ca2+和 H+与 BL 结合的稳定常数：logKZnBL 4.06、logKZnHCO3BL+ 5.15、logKMgBL 3.72、logKKBL 2.62、logKCaBL 1.99 和 logKHBL 4.27。基于这些估算参数，成功开发了 BLM 来预测 Zn 对大麦根伸长的毒性，作为溶液特性的函数。
