重金属对土壤中小麦种子发芽与根伸长抑制的生态毒性

Eco-toxicology of heavy metals on the inhibition of seed germination and root elongation of wheat in soils

测定了4种土壤(红壤、草甸棕壤、暗棕壤和栗钙土)条件下,Cu、Zn、Pb和Cd单一污染对小麦种子发芽与根伸长抑制率及其复合污染效应(暗棕壤条件下)结果表明,同一浓度下,重金属对小麦根伸长抑制率均明显大于对种子发芽抑制率.植物根对重金属污染的生态毒性比种子发芽敏感.土壤有机质和土壤N含量与Cu、Zn、Pb和Cd污染对小麦根伸长抑制率显著负相关(ROR2=0.91,RK-N2=0.92),土壤pH和阳离子交换量与Cu、Zn、Pb和Cd污染对小麦根伸长抑制率的相关性不显著(RpH2=0.62,RCEC2=0.60).在单一污染对小麦根伸长为刺激作用浓度(较低浓度)或为抑制作用浓度下(较高浓度),复合污染均表现为协同作用.

The eco-toxicity of Cu, Zn, Pb, and Cd in the single form was tested with four types of soils( red loam soils, meadow brown soils, chestnut soils, and dark brown soik) and their combined effect was determined with meadow brown soils. The results showed that with the same content of heavy metals, the root elongation was strongly inhabited than the seed germination, and it indicated that root was more sensitive to heavy metals pollution. The inhibition rate of heavy metals pollution on the root elongation (IRHMRE) of wheat was significantly related with the contents of organic matter (OR) and Kjedahl-nitrogen (K-N) in soils (R2OR = 0.91, R2K-N = 0.92). However, IRHMRE was not significantly related with soil pH as did with OR and K-N, so does the content of CEC (R2pH = 0.62, R2CEC = 0.60). Whether under the low concentration of Cu, Zn, Pb, and Cd resulted in an irritated effect in root elongation, or under high concentration resulted in an inhibition effect in the single form, an synergistic effect occurred in the combined form.