Effects of Nitrogen on Vetiveria zizanioides Absorbing and Removal of Prometryn

With Vetiveria zizanioides as the research object, through greenhouse cultivation, sample testing and laboratory analysis, the absorption and removal effects of V.zizanioides on monocotyledonous nutrition was studied under the conditions of high concentration of nitrogen (0.49 mg/L), medium concentration of nitrogen (0.33 mg/L) and low concentration of nitrogen (0.16 mg/L). Results showed that nitrogen could significantly improve the absorption of V.zizanioides root system on prometryn in monocotyledon nutrient solution. Meanwhile, it promoted transfer of prometryn between the root system and stem leaves. When nitrogen concentration level was medium, the minimum residual rate of prometryn in the solution was 1.80%. The maximum removal rate of V.zizanioides on prometryn was 18.07%. When the nitrogen concentration level was low at the 40^th day of test, the residual rate of prometryn in the solution was 1.86%. The removal rate of V.zizanioides on prometryn was 16.51%. V.zizanioides showed better growth trend under medium and low nitrogen levels compared with that at high concentration nitrogen level at the 40^th day of test. In addition, it had better absorption and removal effect on prometryn in monocotyledon nutrient solution.