小青菜对土壤中毒死蜱吸收移动特征研究

UPTAKE AND TRANSLOCATION OF CHLORPYRIFOS RESIDUES IN SOIL BY BRASSICA CHINENSI

以小青菜为供试蔬菜,通过在土壤中添加毒死蜱,进行盆栽试验,研究毒死蜱对小青菜生长的影响、在土壤中的降解速度以及在小青菜中的吸收和转移规律,为蔬菜中农药残留风险评估和蔬菜安全生产提供理论依据。试验结果表明,与对照相比,含有高浓度(>50.0 mg kg-1)毒死蜱土壤对小青菜的生长有显著抑制作用;毒死蜱在不同处理土壤中的半衰期从23.03 d至77.43 d不等;残留于土壤中的毒死蜱能够被种植的小青菜根系吸收并转移至茎叶部分,随着土壤中处理浓度的增加,毒死蜱在小青菜根、茎和叶中的残留量也随之增加,且毒死蜱在小青菜根中的残留量最大,在叶中的残留量最小;土壤中毒死蜱残留量与小青菜根、茎和叶中毒死蜱的含量呈良好的线性关系,线性方程分别为:C根=0.025 1C土壤-0.235 8,C茎=0.012 3C土壤-0.051 7,C叶=0.000 7C土壤+0.011 5。为了实现蔬菜中农药残留从农田到餐桌的全程控制,保证无公害蔬菜的安全生产与供应,首先要对生产基地土壤中的农药残留进行检测,并从源头上进行控制。

A pot experiment with fortified soils was carried out exploring effect of chlorpyrifos on growth of Brassica chinensi,degradation rate of the pesticide in different culture soils,and its uptake and translocation in the plant,so as to provide a theoretical basis for risk assessment of its residue in vegetables and production of safety vegetables.Results show that chlorpyrifos high in concentration（50.0 mg kg-1） inhibited significantly growth of the plant,as compared to control.Chlorpyrifos differed in half-life in soil between treatments,ranging from 23.03 to 77.43 d,and its residue in the soils could be absorbed by the roots of Brassica chinensi and translocated to shoots.With the pesticide in the soil rising in concentration,its residue in vegetable root,stem and leaf increased,being the highest in the roots and the least in the leaf.Amount of chlorpyrifos residues in root was the maximum,but in leaf was minimum.The residues of chlorpyrifos in vegetable root,stem and leaf displayed a significant positive linear relationship with the primary residue in the soil,which could be expressed in the following equations： Croot=0.025 1Csoil-0.235 8,Cstem=0.012 3Csoil-0.051 7 and Cleaf=0.000 7Csoil＋0.011 5.To realize end-to-end control of pesticide residue in vegetables from from field to table,and to ensure production and supply of hazard-free safety vegetables,it is critical to monitor pesticide residues in the soils of the production bases for control at the source.