Study On Physiological Response And Enrichment Ability Of Celosia Argentea And Celosia Cristata To Copper Stress

Heavy metal pollution of soil is becoming more and more serious,and it has become an urgent environmental problem.Phytoremediation has more outstanding advantages than physical and chemical remediation.The key to the application of phytoremediation is the screening of plant materials and repairing mechanism.In this study,we investigated the vegetation of Tonglv mountain mining area in Huangshi city,Hubei province.It was found that there were a large number of well-grown Celosia argentea L..And we analyzed the plants and the soil in 20cm of its root region,indicating that Celosia argentea L.has strong copper tolerance and enrichment.Meanwhile,Celosia cristata L.as related species of Celosia argentea L.was used widely in landscaping.Therefore,in this study,Celosia argentea L.and Celosia cristata L.were used as materials for copper stress research to discuss the seed germination,growth condition,physiological response,copper enrichment characteristics and the difference of copper tolerance of Celosia argentea L.and Celosia cristata L.in order to provide a theoretical basis for Celosia argentea L.and Celosia cristata L.in the phytoremediation application of copper contaminated soil.The main research results are summarized as followings:1.With the increase of copper concentration(0,25,50,100,200,400 mg·L^-1),it showed that the seed germination was affected,the germination vigor decreased,the bud growth and root growth were inhibited.2.Under pot experiment,with the increase of copper concentration(0,400,800,1200,1600,2400 mg·kg^-1),the plant height,root length,fresh weight and biomass of Celosia argentea L.and Celosia cristata L.decreased,and leaves were wilted and sheded seriously,the dark brown roots turn black.3.The cell membrane permeability of Celosia argentea L.and Celosia cristata L.were affected by copper stress.The electrolytic leakage（EL）and malondialdehyde（MDA）content increased with the increase of copper concentration.When the copper concentration≤800 mg·kg^-1,compared with control,there were no significant difference in EL and MDA content of Celosia argentea L.and Celosia cristata L..4.With increased copper stress,the accumulation of active oxygen scavenging of Celosia argentea L.and Celosia cristata L.both by improving the activity of superoxide dismutase（SOD）and Peroxidase（POD）,reducing Catalase（CAT）activity.However,the reaction of ROS defense system of Celosia cristata L.was more intense than Celosia argentea L..Compared with control,amplitude variation of SOD,POD and CAT activities of Celosia cristata L.was larger than Celosia argentea L..5.With increased copper stress,the chlorophyll content of Celosia argentea L.and Celosia cristata L.were decreased.When copper concentration≤800 mg·kg^-1,compared with control,there was no significant difference of Celosia argentea L..However,when copper concentration≤400 mg·kg^-1,compared with control,there was no significant difference of Celosia cristata L..When copper concentration≤800 mg·kg^-1,the OJIP curve of leaf was higher than control in Celosia argentea L.,indicating that the PSII system of Celosia argentea L.was promoted slightly.However,the function of PS II of Celosia cristata L was damaged seriously.6.Under copper stress,the balance of mineral elements in Celosia argentea L.and Celosia cristata L.was destroyed.The content of Na,K,Mg and Fe in roots decreased significantly,while the content in stems,leaves and flowers varied with different positions and concentrations of copper stress.7.With the increase of copper concentration,the enrichment characteristic of Celosia argentea L.and Celosia cristata L.was root>stem>leaf>flower.However,the copper enrichment of Celosia cristata L.was higher than Celosia argentea L..And the bioaccumulation factor（BCF）and translocation factor（TF）of root,stem,leaf and flower of Celosia cristata L.were higher than Celosia argentea L.