西红柿镍毒害的土壤主控因子和预测模型研究

选取我国有代表性的17种土壤,运用生态毒理学方法研究了土壤中外源镍(Ni)对西红柿的毒性,结果发现土壤中外源Ni对西红柿的生长毒性主要受土壤pH值、有机碳含量的影响.在供试淋洗(使用模拟的人工雨水滤洗定量的土壤样品)和非淋洗土壤中,Ni对西红柿生物量50%抑制的毒性阈值(EC50)范围分别从11mg·kg-1到932mg·kg-1和从7mg·kg-1到2055mg·kg-1,其最大值和最小值比例分别达到了85和294倍.土壤pH值是土壤中Ni对西红柿生长毒性的主控因子,进一步引入土壤有机碳因子时,淋洗和非淋洗土壤理化性质和EC50之间回归方程的决定系数R2由0.853和0.743分别提高到了0.925和0.824.利用土壤性状(土壤pH值、有机碳含量)可以较好地预测土壤中外源Ni对西红柿生长的毒性阈值.

Major Soil Factors Controlling Nickel Toxicity to Tomato in a Wide Range of Chinese Soils and the Predictable Models

The influence of soil properties on extraneous Ni toxicity to tomato shoot growth was investigated in a wide range of Chinese soils (17 soils)using ecotoxicology methods. Results showed that the Ni toxicity to tomato was mainly controlled by the soil pH and soil organic carbon content. The effective concentration of added Ni causing 50% inhibition (EC50)ranged from 11 to 932mg·kg -1 in leached soils which were leached using artificial rain water, and from 7 to 2055mg·kg -1 in unleached soils for the tomato test, respectively, and the ratios of maximum to minimum of EC50 for leached soils and unleached soils were 85 and 294. Soil pH was the main factor controlling the toxicity of Ni in these soils. When taking into account the effect of soil organic carbon content on EC50 values, determination coefficients(R2)of the regression models between soil physico -chemical properties and EC50 values were increased from 0.743 to 0.824 in unleached soils and from 0.853 to 0.925 in leached soils, respectively. It was demonstrated that using soil properties, like pH, organic carbon content as indicators could predict the toxicity of extraneous Ni in soils to tomato shoot growth.