不同性质土壤中钼的植物毒性及预测模型

Phytotoxicity and prediction models of molybdenum in soils with different properties

以我国9个地区不同理化性质的土壤为研究对象,通过外源添加钼酸盐(Mo^(6+))评估了土壤Mo对大麦(Hordeum vulgare L.)的毒性,在此基础上分析了土壤性质因子和毒性阈值之间的相关性,并建立了一元和多元线性回归方程。结果表明,在9个地区的土壤中,Mo对大麦根伸长10%抑制率(EC_(10))和50%抑制率(EC_(50))的变化范围分别为262.64~3301.70 mg·kg^(-1)和851.10~5142.62 mg·kg^(-1);土壤阳离子交换量(CEC)是影响土壤Mo毒性阈值最重要的因子;基于CEC建立的回归方程中引入pH值和锰氧化物含量时,预测能力显著提升,可以分别解释EC_(10)和EC_(50)的82.2%和88.5%的变异(P<0.05)。利用欧洲9个地区土壤的大麦毒性数据对模型进行验证,发现基于我国土壤建立的Mo毒性预测模型并不适用于欧洲土壤,进一步分析了我国和欧洲18个地区的土壤性质和毒性阈值的相关性并建立了预测模型。研究表明,CEC对Mo的大麦毒性有显著影响,基于CEC、pH值和锰氧化物含量建立的预测模型可以准确评估我国和欧洲18个地区土壤Mo的毒性。本研究可为土壤Mo的风险评价和修复提供重要参考。

In this study,we selected nine representative soil samples in China with different physical and chemical properties.The toxicity of Mo to barley(Hordeum vulgare L.)was evaluated by adding molybdate(Mo^(6+)),the correlation between soil properties and toxicity threshold was determined,and unary and multiple linear regression equations were established.The results indicated that in the nine soils with different properties,the effective concentration that resulted in 10%inhibition rate(EC_(10))and 50%inhibition rate(EC_(50))on barley root elongation ranged from 262.64 mg·kg^(-1) to 3301.70 mg·kg^(-1) and from 851.10 mg·kg^(-1) to 5142.62 mg·kg^(-1),respectively.Soil cation exchange capacity(CEC)was the most important factor that affected the toxicity threshold of Mo.When pH value and manganese oxide content were introduced into the regression equation based on CEC,the predictive ability was significantly improved,and the model could explain 82.2%and 88.5% of the variation of EC_(10) and EC_(50),respectively(P<0.05).Toxicity data of barely in nine European soils were used to verify the model,and the results indicated that the predictive model for Chinese soils was not applicable to European soils.Therefore,the correlation between soil properties and toxicity threshold was further analyzed in eighteen Chinese and European soils,and a predictive model was established.The results indicated that CEC had significant effect on the toxicity of Mo to barley.The predictive model based on CEC,pH value,and manganese oxide content could be used to accurately assess the toxicity of Mo in eighteen Chinese and European soils.This study provides important reference for risk assessment and remediation of Mo in soils.