磺胺间甲氧嘧啶-镉复合污染对作物种子发芽的影响

Joint toxicity of sulfamonomethoxine and Cd on seed germination and root elongation of crops in soil

测定了黄潮土中常用兽药磺胺间甲氧嘧啶(SMM)与重金属镉(Cd)单一及复合污染对小麦和西红柿种子发芽(根伸长、芽伸长和发芽率)的影响,分析了土壤中药物浓度与作物生长抑制的剂量-效应关系及复合污染的毒性效应.结果表明,在单一污染物作用下,根伸长抑制率和芽伸长抑制率与药物浓度显著相关(P<0.05),发芽抑制率与药物浓度不相关(P>0.05);药物对根伸长及芽伸长的抑制高于对种子发芽的抑制;SMM对2种作物的毒性效应明显强于Cd,SMM对小麦和西红柿根伸长的IC50(抑制率为50%时污染物浓度)分别为33.7,49.3mg/kg,而Cd为507.3,599.8mg/kg.SMM和Cd复合污染时,在低Cd(200mg/kg)的胁迫下,联合作用主要体现为协同作用,但随着SMM浓度的增加,协同效应不显著(P>0.05);在高Cd(500mg/kg)作用下,二者的联合效应中Cd起主要作用.

The single and joint effects of sulfamonomethoxine（SMM） and cadmium（Cd） on seed germination rate and shoot/root elongation of wheat（Triticum aestivum L.） and tomato（Solanum lycopersicum） in yellow fluvo-aquic soil were investigated.In the single-factor experiments,there was a dose-response relationship between the concentration of SMM or Cd and the inhibitory rate of crop root elongation and shoot elongation（P〈0.05）,but no correlation was found between the concentration of each pollutant and the inhibitory rate of crop seed germination（P〉0.05）.The inhibitory effect of each pollutant on root and shoot elongation was much stronger than those on seed germination.SMM showed a much higher toxic effect on crops than did Cd.The IC50（half inhibition concentration） values of SMM on root elongation of wheat and tomato were 33.7,49.3 mg/kg,respectively,the corresponding values of Cd were 507.3,599.8 mg/kg,respectively.In the joint effect tests,SMM and Cd showed a synergic effect on root and shoot elongation when the concentration of Cd was at 200 mg/kg.However the synergic effect was not significant with the increase of SMM concentration（P〈0.05）;At the high concentration of Cd（500 mg/kg）,joint toxicity of SMM and Cd was more dependent on Cd.