Abstract: The eco toxicity of Cu,Zn,Pb and Cd in the single form on the inhibition of seed germination and root elongation of turnip was tested with four types of soils (red loam soils,meadow brown soils,chestnut soils and dark brown soils),and their combined effect was determined with meadow brown soils.Data showed that with the same content of heavy metals,the root elongation was more strongly inhibited than the seed germination,indicating that root is more sensitive to heavy metals pollution than seed germination.The inhibition rates of heavy metals on the root elongation (IRHMRE)of turnip were significantly negatively related to the contents of organic matter (OR) and Kjedahl nitrogen (KN) in soils.However,there were no significant relationship between IRHMRE and soil pH,and so does the content of T K.A slight antagonism effect in root elongation was produced when Cu,Zn,Pb and Cd were combined in the concentrations.Zn,Pb and Cd resulted in the incentive effect,while Cu gave an inhibition in the single form.Furthermore,additive effect was shown when Cu,Zn,Pb and Cd were combined in the inhibition concentrations(IC>10%)of single form.

Key words: maize, hybrid, shade-humid environment, index.