Effects Of Levofloxacin Hydrochloride On Growth And Physiological Characteristics Of Rice, Maize And Wheat

Antibiotics could enter a crop filed by many ways,such as wasterwater irrigation,application of organic manure.They have become one of new pollutants affecting the growth and development in crops.This study discussed the effects of Levofloxacin Hydrochloride(OFLX) on the seed germination and seedling growth of rice,maize and wheat,with the chlorophyll, soluble protein content and components,root activity and antioxidant enzyme systems.It provided scientific basis assessing ecological risk of the antibiotics to crop.The results were as follows:OFLX had no significant effects on seed germination rate,germination potential and germination index of rice.Seed germination vigor index,the seedling height,the number of roots,roots length,chlorophyll content declined with rise of OFLX concentration.As OFLX concentration was increased, the activities of superoxide dismutase(SOD),peroxidase(POD) in endosperm showed first increasing and then decreasing trend,the activities of catalase(CAT) declined gradually.The chlorophyll content of rice leaves declined with increasing of OFLX at concentration below 500mg.L^-1.With concentration of OFLX increasing,the activities of SOD were increasing,the activities of POD and CAT were declining.Soluble protein content of leaves increased with the concentrations of OFLX increasing.SDS-PAGE analysis showed that no notable change of soluble protein was observed for control and OFLX treated samples.Root activity increased after treatment with OFLX concentration below 0.3mg.L^-1and decreased as the concentration of OFLX further increased.At the same time,the seed germination rate,germination potential and germination index of maize decreased with increasing concentration of OFLX.As OFLX concentration was increased,the seed germination vigor index,the seedling height,root length,the number of root, chlorophyll content and the activities of SOD,POD and CAT in endosperm showed first increasing and then decreasing trend. Otherwise,OFLX had an inhibitory effect on chlorophyll content of wheat leaves.With increasing concentration of OFLX,the activities of SOD and POD of wheat leaves showed first increasing and then decreasing trend,which were higher than those of control,at the same time,the activity of CAT was increasing.Soluble protein content of leaves increased under OFLX stress,which played an important role in resisting stress. Root activity declined after treatment with OFLX concentration below 500mg.L^-1,which had an effect on the growth of wheat shoot.All of these suggested that OFLX inhibited the growth and development of rice,maize and wheat.The damage of corps was a complicated process,which might be related to the functional damage of antioxidant enzyme systems,chloroplasts and roots. Under the action of OFLX,crop could make protective reaction to external bad environment though its own enzyme mechanisms, but stress resistance of crop was bad.OFLX immediately intimidated agricultural producation safety and need enhance regulation.