土霉素对小麦种子发芽与幼苗生长发育的生态毒性

Ecotoxicological Effects of Oxytetracycline on Wheat(Triticum aestivum) Based on Seed Germination and Seedling Development

研究了土霉素对小麦种子发芽以及早期幼苗生长发育的生态毒性效应.结果表明,土霉素对小麦种子芽长及根长的抑制效应显著（p〈0.01）,而且它们之间具有良好的剂量-效应关系.根据线性回归方程得出土霉素对小麦种子芽长和根长的半抑制浓度为65.5 mg/L和34.7 mg/L.然而,土霉素对小麦种子的发芽率并没有显著的影响.研究还表明,0.15～2.4 mg/L土霉素暴露21 d后,小麦叶片中的叶绿素含量降低了35.6%～47.3%,叶片及根部的可溶性蛋白含量也均呈显著下降趋势.暴露7 d后,0.15～2.4 mg/L土霉素对小麦叶片和根部SOD与POD活性的抑制效应不显著,但随着暴露时间的延长,土霉素对小麦的SOD与POD酶活性抑制率显著下降;2.4 mg/L土霉素暴露21 d后,小麦根部的SOD活性下降72.3%,说明土霉素对小麦幼苗体内的抗氧化系统具有破坏作用.该实验结果显示,低浓度土霉素长期暴露对小麦幼苗的生长发育具有不良的生态毒性效应.

The ecotoxicological effects of oxytetracycline（OTC） on the germination of wheat（Triticum aestivum） seeds and the early development of wheat seedlings were investigated.The results showed that the elongation of wheat shoots and roots was significantly（p〈0.05） inhibited by OTC,and there was a good dose-response relationship between the OTC concentration and inhibition rates.According to the linear regression equation,EC50of OTC for inhibiting wheat shoot and root elongation was 65.5mg/L and 34.7mg/L,respectively.However, the germination of wheat seeds was not inhibited by OTC.Moreover,after a 21day exposure to 0.15-2.40mg/L OTC,the content of chlorophyll（CHL） decreased by 35.6%-47.3%,and the content of soluble protein（SP） in the leaves and roots of wheat plants decreased significantly.After a 7-day exposure,the activity of SOD and POD in wheat was not changed significantly.With the prolongation of exposure time,the activity of SOD and POD in wheat leaves and roots decreased significantly,the inhibition rate of SOD activity in roots increased up to 72.3% after a 21-day exposure to 2.4mg/L OTC,which indicated that the antioxidant defense systems were damaged.The results above suggested that the low concentration OTC had ecotoxicological effects on wheat seedlings after chronic exposure.