Study On Antimony Enrichment And Tolerance Mechanism Of Cell Wall In The Subcell Of Pteris Vittata L.

Antimony(Sb)is a toxic heavy metal element and P.vittata is a common plant with high concentration in southwest China.In this paper,the mechanism of antimony enrichment and tolerance in the cell wall of P.vittata was studied.To investigate the content of antimony in the subcellular components of P.vittata under antimony stress and the changes of total sugar and galacturonic acid in cell wall pectin and hemicellulose.Chemical modification of cell wall,adsorption dynamic experiments and the FTIR spectroscopy analysis were combined to explore adsorption kinetic characteristics and the functional groups of the cell wall and its components under antimony stress.The main conclusions are as follows:(1)The distribution characteristics of antimony under different concentration of antimony stress in cells of root,stem and leaf of P.vittata were determined by differential centrifugation.Antimony was mainly enriched in the root of P.vittata,and a small amount in stem and leaf.The results showed that the root of P.vittata had strong resistance to antimony,which weakened the further toxicity of antimony to stem and leaf of P.vittata.As a whole,the content of antimony in subcellular cells is cell wall>soluble component>protoplast>mitochondria.This confirms that the cell wall plays a major role in the process of P.vittata reaching antimony resistance.(2)The adsorption kinetics experiment showed that the cell wall of P.vittata root had high affinity to antimony.The antimony content adsorbed by the root cell wall was close to its saturation level after 100 minutes,which was about 95% of the maximum adsorption capacity.We obtained a saturated adsorption capacity of antimony after 450 min,with 25.01 mg/g.The adsorption kinetics experiments of P.vittata showed that pectin was the main part of antimony adsorption fixation.The adsorption effect of antimony decreased 14.63% by reducing the degree of methyl esterification of pectin.In addition,under the condition of hydroponics,the FTIR of P.vittata under antimony stress was studied.The stress concentration of 40 mg/L was the critical value of root of P.vittata,and the critical value of stem and leaf was 60 mg/L.When it exceeded this critical value,plants can be poisoned to a certain extent,while affecting their normalphysiological and biochemical activities.(3)The change of polysaccharides' concentration in cell wall is closely related to the process of cell detoxification.The tolerance of P.vittata to antimony was increased by changing the content of cell wall components.The content of polysaccharide components in the cell wall changes with increasing concentration of antimony ion stress.The total sugar content of total pectin,chelated pectin and hemicellulose I increased significantly,while the contents of basic pectin and hemicellulose II decreased significantly.Only the concentration of galacturonic acid of alkaline pectin in leaf decreased,the content of galacturonic acid in root,stem and leaf increased.In this way,P.vittata reduces damage to its internal organelles by accumulating large amounts of antimony on its cell walls.This study shows the important role of the cell wall,especially the cell wall polysaccharide,in the detoxification of Antimony.