Study On The Distribution Characteristics And Toxicological Mechanism Of Sb In Houttuynia Cordata Thunb

China is the country with the most abundant antimony resources in the world.The exploitation and use of antimony lead to environmental pollution.The research of antimony in plants mainly involves the physiological and biochemical indexes,such as the influence of growth and development,the activity of enzymes and protein,the absorption of nutrient elements,and root exudates,the toxic mechanism of subcellular ultrastructure and functional group is not involved.In this paper,Houttuynia cordata Thunb as the research object,the existing form of antimony in Houttuynia cordata Thunb,the distribution characteristics of subcellular,the stress response of cell ultrastructure to antimony,the combination of antimony and functional groups in subcellular,the distribution characteristics of Sb in Houttuynia cordata Thunb subcellular and its toxic mechanism were studied,to provide scientific basis for further study on health risk control and toxicology of Houttuynia cordata Thunb.The main conclusions are as follows:?1?The content of antimony in different parts of Houttuynia cordata Thunb was as follows:root>leaf>stem,In Houttuynia cordata Thunb,Sb is mainly in residual form?F_R? and hydrochloric acid extraction form(F_HCl) with low activity state.The content of Sb in root residual form?F_R?,hydrochloric acid extraction form(F_HCl) and acetic acid extraction form(F_HAC)reaches1245.76 mg/kg?1432.84 mg/kg?514.04 mg/kg.?2?The distribution of Sb content in the root,stem and leaf subcellular of Houttuynia cordata Thunb shows a certain regularity.In the root cell wall>soluble component>organelle?protoplast and mitochondria?,the stem is mainly distributed in the cell wall and organelle?protoplast and mitochondria?,the leaf is mainly distributed in the cell wall and soluble component,and the Sb content in the cell wall and soluble component is the highest reaches 1443.28 mg/kg and 1318.98 mg/kg,the proportion of Sb in cell wall and soluble component is the highest reaches 87.22% and 83.19%,the content of Sb in mitochondria and protoplasts is the highest reaches 37.29% and 46.89%.?3?60 mg/L Sb??? and Sb??? under stress,the subcellular structures of roots,stems and leaves of Houttuynia cordata Thunb were damaged to different degrees,the surface structures of mitochondria and chloroplasts were broken,the ridge convex structures disappeared,the internal structures were exposed and vacuoles were formed,the cell wall structure was fuzzy and deformed,the cell membrane was separated from the substance wall,and the black substance containing Sb was found in the vacuoles,which was detected by TEM-EDS entering the vacuole of Houttuynia cordata Thunb,the black substance was formed.The mechanism of the resistance of Houttuynia cordata Thunb to Sb was mainly manifested in the fixation of cell wall and the compartmentalization of vacuole.?4?Sb????Sb??? under stress,the content of protein,polysaccharide,pectin and cellulose in the cell walls of roots,stems and leaves of Houttuynia cordata Thunb increased,and Sb mainly interacted with them,forming complex adsorption and complexation on the cell walls,reducing the migration and diffusion ability of Sb.In the Houttuynia cordata Thunb subcellular??OH/?NH???C?H???C?N???C?C/C?O????C?H/?C?C/?C?O???C?C/C?O???COO-?the shift of the characteristic peak is large,which combines with antimony.