Study On The Accumulation And Resistance Of Antimony In Houttuynia Cordata Thunbto

This paper set Houttuynia cordata Thunbto—medicine and food plants as the research object,adopt the method of solution culture,applying different concentrations(5,10,15,20,30,50 mg/L)of Sb(Ⅲ)and Sb(Ⅴ)stress,by measuring its leaf malondialdehyde(MDA)content,superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)activity and soluble sugar(SS),soluble protein(SP),auxiliary glycine(Pro)content changes of the characterization of Houttuynia cordata Thunbto physiological response to stress of antimony and adjustment mechanism of oxidation reaction;By determining its root and aboveground part different valence state of antimony content,preliminary understanding the accumulation of antimony in Houttuynia cordata Thunbto absorption characteristics between valence state transformation,so as to provide foundation support for Houttuynia cordata Thunbto antimony repair contaminated soil;Through the determination of antimony stress under its aboveground and underground parts of nonprotein sulfhydryl group peptide(NPT)and reduced glutathione(GSH),plant chelating peptide(PCs)and metallothionein(MT)content,understand its polypeptide substance in adversity environment chelating reaction.The main conclusions are as follows:(1)Houttuynia cordata Thunbto under the stress of antimony,protective enzymes and osmotic regulation substances in the body change accordingly,eliminate excessive reactive oxygen species,stable structure of biological cells,adjust cell osmotic concentration,have the effect of slow harm.As the main indicator of the degree of membrane lipid peroxidation,MDA reflects the changes of free radical in plants under adverse conditions.The overall trend of MDA changes is that in the low concentration(0~10mg/L),the concentration(10~20mg/L)gradually decreases,and the higher concentration(20~50mg/L)continues to rise.MDA change again and again,which is associated with the change of the protective enzyme in the body,stress of initial Houttuynia cordata Thunbto phenomenon,membrane lipid peroxide as protective enzyme system startup,the part to eliminate free radicals,slow the membrane lipid peroxidation level,and with the increase of stress concentration,protective enzyme activity also declined trend,the MDA levels continue to rise Houttuynia cordata Thunbto three protective enzymes in the body including SOD,POD,CAT,they all activity as the processing levels showed a trend of decline after rising first,low concentration(0~15mg/L)of antimony stimulation,the body’s defenses and resistance characteristics of physical activity by stimulating speeding up,the activities of antioxidant enzymes in the rapid rise in their own defense system,in response to the body caused by the increase of reactive oxygen species from poison,and elevated concentrations(20~50mg/L),the accumulation of heavy metal ions in the body,effects on plants,many functions in the cell membrane and enzyme system was destroyed,active instead is restrained began to decline Houttuynia cordata Thunbto three osmotic regulation substances in the body including SS,SP and Pro,SS and is related to the level of processing a large number of synthetic SS to maintain tissue water balance,and SP due to various enzymes involved in metabolism,including protectiveenzyme system,thus presents the negative correlation tendency,presents the downward trend after rising first,Pro content peaked at 10 mg/L,maybe and SS combination results in the decrease of high concentration of Pro content.Additional analysis of protective enzyme activity,osmotic regulation substances and antimony content change of correlation coefficient,the results showed that SOD activity,SS and SP content on Sb(Ⅲ),Sb(Ⅴ)stress sensitivity is higher,the three indicators can be as identification of h.cordata under the stress of antimony,looks like the physiological indicators.(2)Its rejection mechanism under the stress of antimony,regardless of Sb(Ⅲ),Sb(Ⅴ)stress,antimony after entering Houttuynia cordata Thunbto are mainly distributed in the root,and Sb(Ⅲ)stress transfer coefficient is 0.09~0.17,Sb(Ⅴ)stress transfer coefficient is 0.04~0.07,shows that its limit antimony off to the ground part,slow poison.With the increase of Sb(Ⅲ)stress levels,h.cordata Sb(Ⅲ),Sb(Ⅴ)levels were significantly elevated,Sb under 50 mg/L(Ⅲ),Sb(Ⅴ)content reached its highest 3304.63 mg/kg and 368.01 mg/kg,aboveground enrichment coefficient is10.41~16.14;Sb(Ⅴ)under duress,Houttuynia cordata Thunbto in Sb(Ⅲ),Sb(Ⅴ)content also showed a trend of obvious rise,50 mg/L in processing Sb(Ⅲ),Sb(Ⅴ)content reached its highest771.02 mg/kg and 2813.28 mg/kg,aboveground enrichment coefficient is 4.60 ~ 8.98.Houttuynia cordata Thunbto for Sb(Ⅲ)had higher enrichment coefficient,instructions for Sb(Ⅲ)absorption ability is stronger than Sb(Ⅴ).The aboveground and root of the hernia were mainly Sb(s),and the percentage of the aboveground and the root Sb(s)was as high as 85.49% and 90.72% respectively.And Sb(Ⅴ)under duress,mainly Sb(Ⅴ)in the root,content range between 77.72% ~ 80.02%,after running to the ground part is given priority to with Sb(Ⅲ).Analogy of antimony kin element arsenic,plants of arsenate reductase or glutathione reductase As(Ⅴ)can be revert to the As(Ⅲ),so there may be a similar function in plant body material to complete the conversion.(3)plants under heavy metal stress,plants non-protein thiol peptide(NPT),glutathione(GSH),plant chelating peptide(PCs)and metallothionein(MT)with heavy metals and other substances can complexation reaction,reduce the toxicity of heavy metals.Experimental results show: with Sb(Ⅲ)concentration increases,its root and aboveground NPT,content of GSH and PCs were lower after increase first,in 15~20 mg/L range to the maximum,and the content of the root is higher than the earth.With Sb(Ⅴ)concentration increases,its root and aboveground tissues and organs of the NPT,content of GSH and PCs all showed a trend of rise,when 50 mg/L to the maximum.Sb(Ⅲ)and Sb(Ⅴ)stress process causes of differences is high concentration(20~50mg/L)within the scope of Sb(Ⅲ)> Sb(Ⅴ)toxicity,more damage to the plant,the high concentration range of Sb(Ⅲ)under stress,the NPT,cut down the content of GSH and PCs,and less toxic Sb(Ⅴ)plant is still able to produce resistance.The content of the root NPT,GSH and PCs is higher than that in the ground,which may be the first plant organ under stress due to the root system in the underground part.When the subterranean part was induced by the subterranean part,the accumulation amount was correspondingly lower than that of the underground part.