The Re Mediation Potential And Response Of Bidens Pilosa And Chromolaenaodorata On Atrazine In Soil

Bidens pilosa L.?an annual forb?,and Chromolaena odorata L.?a rapidly growing perennial herb?fromthe family of Compositae were reported to be the most problematic invasive species in subtropical area in C hina.Atrazine is a widely used herbicide worldwide and is the most frequently detected organic contaminants in groundwater worldwide which pose a significant threat to the growth of crops,drinking water and soil.In this study,we aimed at assessing the ecological responses of the two invasive plants and usefulness of utilizing two invasive plants?Bidens pilosa L.andChromolaena odorata L.?to remedysoil pollution by Atrazine.The results are as follows:?1?Both Bidens pilosaand Chromolaena odorataaccelerated the degradation of atrazine,andChromolaena odoratais more effective.After 24 days,the degradation rate of Chromolaena,Bidens and bare soil was 96.5-99.5,90.4-93.0 and 79.0-85.0%respectively.With the 3.2 mg·kg^-1 and 4.8 mg·kg^-1 concentration of atrazine treatments,the bioconcentration indexes of Chromolaena were 1.32 and 2.20 respectively,while Bidens's weremerely 0.21 and 0.16 respectively;the removal indexes of Chromolaena were0.30 and0.37 respectively,while Bidens's were 0.55 and 0.80 respectively.?2?Atrazine had significant impacts on the growth of Bidensand Chromolaena,significantly declinedthe height,biomass,chlorophyll content and chlorophyll fluorescence parameter of the two species.The inhibition rate of radicle and shoot of the two plants increased asthe atrazine concentration increased.Low concentration of atrazine promoted the germination of Bidenswhile inhibited itsgerminationin the higher concentration.Germination rate of Chromolaena decreased as the atrazine concentration increased.?3?After 120 days,with the increase of atrazine concentration,both Bidens andChromolaena leaves'soluble protein content,catalase?CAT?content and peroxidase?POD?increased at low atrazine concentration and declined at high atrazine concentration.Thisphenomenon indicated that atrazine promote the soluble protein and anti-oxidase at low concentration and inhibit at high concentration.?4?At the 120th day of atrazine treatments,the content of available nitrogen,available phosphate and available potassium all declined with the increase of atrazine concentration.pH increased under the treatment of Bidens,while pH had no significant change under the treatment of Chromolaena.This phenomenon possibly indicated that atrazine destroy the available nutrient in soil under the phytoremediation of invasive plants.In conclusion,both Bidens and Chromolaena has potential to repair atrazine in soil,whilethe phytoremediation of Chromolaena is better than Bidens.However,atrazine significantly impacts the growth of both Bidens and Chromolaena,causing the decline of height,chlorophyll content,photosynthetic efficiency,etc.