不同土壤条件下镉对番茄根系的毒害效应及其毒害临界值研究

Toxicity and Its Threshold of Cadmium to Tomato Roots in Different Soils

采用盆栽试验研究了在8种土壤上外源添加镉(0～16 mg·kg-1)对番茄根系的毒害效应以及影响镉对番茄根系毒害临界值的主要土壤性质。结果表明,随着土壤镉添加量的增加,不同土壤上镉对番茄根长和根鲜重的影响存在较大差异。不同土壤上番茄根长降低20%时的毒害效应浓度(EC20,0.1 mol·L-1CaCl2提取的土壤有效镉)介于0.26～11.61 mg·kg-1之间,而不同土壤上番茄根系生物量的EC-20值介于0.01～5.07 mg·kg1之间。土壤pH值是影响番茄根长EC20的主要土壤性质,随着土壤pH值的升高,土壤镉的毒害效应降低,EC20值升高。土壤有机质含量是影响番茄根系生物量EC20的主要土壤性质,土壤镉的毒害效应随土壤有机质含量的增加而减弱,EC20值随之升高。

A pot experiment was conducted to study the toxic effects of different addition levels of Cd（0～16mg·kg^-1）on tomato roots and the soil properties affecting Cd toxicity thresholds at which tomato root length or biomass reduced by 20%（expressed as EC20）in 8 different soils. The effects of Cd on the length and biomass of tomato roots showed great differences among various soils. The thresholds for root length were between 0.26mg·kg^-1and 11.61mg·kg^-1 of available soil Cd（0.1 mol·L^-1CaCl2-extractable Cd）and from 0.01mg·kg^-1to 5.07mg·kg^-1for root biomass. Soil pH was a key factor affecting the EC20 values for root length,which increased with soil pH. However,the EC20 for root biomass was primarily influenced by soil organic matte（rSOM）contents,with EC20 increased with soil SOM.