Inhibition and Toxicity of Cu,Zn,Pb on Root Elongation of Vegetable in Contaminated Soil

A pot experiment was conducted to observe the root elongation of leaf vegetables(pakchoi and cabbage),root vegetables(radish and onion),solanaceous vegetables(tomato and cucumber) in paddy soil which was polluted by different heavy metals at different concentrations(Cu 0～2 000 mg·kg-1,Zn 0～3 000 mg·kg-1,Pb 0～5 000 mg·kg-1) in greenhouse,in order to clarify the inhibition and toxicity effects of different heavy metals on vegetables.The results indicated that the inhibition rate in tomato was the highest and the pakchoi was the lowest in the same concentrations of Cu,Zn and Pb contamination,so tomato was the most sensible to Cu,Zn,Pb,and pakchoi was insensible.The vegetables responded differently to different heavy metals,more sensible to Cu(copper) than to Zn(Zinc) and Pb(lead).A significantly negative relationship was found between root elongation and available concentrations of heavy metals in the involved soil(rCu=-0.782*,rZn=-0.995**,rPb=-0.982**).In conclusion,the available heavy metal was one of the important factors in affecting root elongation of vegetables.