Inhibition Effects of Cu,Zn and Pb on Root Elongation of Tomato in Three Typical Contaminated Soils of China

A pot experiment in greenhouse was conducted to observe the root elongation of tomato which were sensitive to heavy metals in three typical soils (paddy soil,cinnamon soil,red soil) of China,which were polluted by Cu,Zn and Pb. The application levels were Cu(0~2000mg·kg-1),Zn(0~4000mg·kg-1),Pb(0~5000mg·kg-1) in paddy soil and cinnamon soil,while in red soil,the levels were Cu(0~400mg·kg-1),Zn(0~750mg·kg-1),Pb(0~2000mg·kg-1),respectively. In order to clarify the inhibition effects of different heavy metals at different application levels on tomato root elongation in various contaminated soils,the inhibition ratio of root elongation of tomato in the soils were measured and compared. Results indicated that,the order of the inhibition ratio of root elongation of tomato at same application levels of Cu,Zn,Pb was as follows: red soilpaddy soilcinnamon soil. Tomato responded differently to various heavy metals,Cu was more sensible than Zn and Pb. Significantly negative relationships were found between root elongation and available contents of heavy metals in the involved soils(p0.05; p0.01),which implied that the available heavy metal in soil was one of the important factors affecting root elongation of vegetables.