Effects Of Atrazine On Growth And Reactive Oxygen Metabolism Of Pennisetum Hydridum

This study was to investigate the effect of atrazine stress on the growth of Pennisetum hydridum.Pot experiments were conducted to study the effects of atrazine stress (0,20,50,100,200,500mg· kg^-1)on plant height, biomass, root-shoot ratio and chlorophyll content of P. hydridum. Hydroponicsexperiments were conducted to study the effects of atrazine stress (0,5,10,20,40mg· L^-1) on O-2production rate, H₂O₂content, activities of Superoxide dismutase （SOD）, Catalase （CAT） andPeroxidase （POD）, Malondialdehyde （MDA） content, plasma membrane permeability and antioxidantcapacity in leaves of P. hydridum..20and50mg· kg^-1of atrazine stress showed no significant effects on plant height and biomass ofP. hydridum.100and200mg· kg^-1of atrazine stress did not show significant effect on plant height, butdid on the biomass of P. hydridum. Biomass of P. hydridum stressed by100and200mg· kg^-1ofatrazine was decreased by34.1%and36.4%compared with control, respectively.500mg· kg^-1ofatrazine stress brought significant decrease in plant height（by40.6%） and biomass（20.0%） of P.hydridum. All levels of atrazine stress showed no significant effects on root-shoot ratio and chlorophyllcontent of P. hydridum.5and10mg· L^-1of atrazine stress elevated O2-production rate and CAT activities in leaves of P.hydridum, and decreased H₂O₂content, antioxidant capacity, activities of SOD and POD. Withprolonging of culture time, the above indexes have returned to normal levels, but40mg· L^-1of atrazinestress decreased H₂O₂content, antioxidant capacity, activities of SOD, CAT and POD in leaves of P.hydridum continuously. After10days, MDA content in leaves of P. hydridum treated by all levels ofatrazine stress began to increasing. With the increasing of atrazine concentration, the increasingamplitude of MDA content was significantly increased. All levels of atrazine stress showed nosignificant effects on plasma membrane permeability in leaves of P. hydridum. Grey relational gradeanalysis between antioxidant capacity and reactive oxygen metabolism indices in leaves of P. hydridumindicated that the relationship of antioxidant capacity with activities of SOD, plasma membrane permeability and O₂-production rate was more intimate than other indices.