除草剂咪唑烟酸和高效氟吡甲禾灵对互花米草光合特性的影响OA

To compare the effects of imazapyr acid(IA)and haloxyfop-P-methyl(HPME)herbicides on treatment efficacy and photosynthetic characteristics of Spartina alterniflora,this study used cloned seedlings as experimental materials and treated them with IA water solution and HPME emulsion.Chlorophyll content,photosynthetic physio-logical indexes and daily dynamic changes in S.alterniflora under continuous herbicide stress were measured and analyzed.The results show that the net photosynthetic rate(Pn),transpiration rate(Tr),and stomatal conduct-ance(Gs)of S.alterniflora decreased significantly,while intercellular CO2(Ci)increased significantly(P<0.05)as herbicide stress duration increased.Under IA stress,the diurnal variation curves of Pn,Tr,Gs and Ci exhibited a unimodal pattern,with no obvious photosynthetic"midday depression"phenomenon.In contrast,under HPME stress,these diurnal curves showed a bimodal pattern,with a distinct midday depression in photosynthethesis.One week after IA and HPME application,photosynthesis in S.alterniflora was severely inhibited.IA,a slow-acting herbicide,lead to S.alterniflora death in approximately 60 days,whereas HPME,a fast-acting herbicide,caused greater sensitivity to environmental factors and resulted in plant death in around 30 days.These findings provide a theoretical basis for future management of S.alterniflora.