| A solution experiment of simulated water environment was conducted to study the toxic effects of low concentration（2~8 mg·L-1）copper oxide nanoparticles（CuONPs） on Ceratophyllum demersum. The same concentrations of copper oxide micronparticle（CuOMPs） and the Cu2+ corresponding to CuONPs were compared. The experimental results showed that the concentrations of Cu in Ceratophyllum demersum growing in CuONPs solution were about 6~12 times than the concentrations exposing in CuOMPs solution.When Ceratophyllum demersum were cultured for 20 d ,the activities of POD and SOD reached the maximum values under the stress of 4 mg·L-1 CuONPs solution and when the Ceratophyllum demersum were cultured for 30 d,the chlorophyll-a level reached a peak at the same concentration.Under the stress of comparable Cu2+ concentration（0.23 mg·L-1） of 8 mg·L-1 CuONPs, the activities of POD and SOD, the chlorophyll-a level were significantly less than those influenced by 8 mg·L-1 CuONPs solution. These results indicated that the CuONPs solution of low concentrations（4~8 mg·L-1） had the restraining or toxic effects on the growth of Ceratophyllum demersum. The CuONPs solution exhibited the remarkable ecological effects with nanoparticle characters, as well as the time scale effects for the growth of Ceratophyllum demersum. But the CuOMPs solution of low concentration had no observed toxic effects on Ceratophyllum demersum. |
