我国典型土壤上重金属污染对番茄根伸长的抑制毒性效应

采用盆栽试验观测了我国3种典型土壤——黄泥土、褐土、红壤上不同重金属(铜、锌、铅)作用下敏感植物番茄的根伸长,其中黄泥土和褐土上重金属添加量范围为Cu(0～2000mg·kg-1)、Zn(0～4000mg·kg-1)和Pb(0～5000mg·kg-1),红壤上为Cu(0～400mg·kg-1)、Zn(0～750mg·kg-1)和Pb(0～2000mg·kg-1).对不同土壤上Cu、Zn、Pb对番茄的根伸长抑制率进行了比较,以阐明不同土壤上重金属种类及用量对蔬菜根生长的抑制及毒性效应.结果表明,相同Cu、Zn、Pb污染水平(添加量)下,土壤中重金属对番茄的根伸长抑制率大小顺序基本表现为:红壤>黄泥土>褐土.番茄对红壤中的重金属最敏感,其次是黄泥土,再次是褐土.番茄对不同重金属的毒性响应不同,对Cu最敏感,Zn和Pb次之.土壤中有效态重金属含量与番茄根伸长呈显著(p<0.05)或极显著(p<0.01)负相关,表明有效态重金属含量是影响蔬菜根伸长的重要因素.

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 soil>paddy soil>cinnamon 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(p<0.05; p<0.01),which implied that the available heavy metal in soil was one of the important factors affecting root elongation of vegetables.