Regulation Effects Of Arbuscular Mycorrhizal Fungi(AMF) On Phytoremediation Of Sorghum Haipense Incesium Contamination Soils

At present, nuclide cesium pollution in the soil is increasingly serious, plant extraction technology is the most commonly used method of bioremediation, but because cesium can inhibit the growth of plants, plant bio mass was to be a restraining factor for it. The study found that irbuscular mycorrhizal fungi (AMF) is an endotrophic mycorrhizal fungi, interact with the roots of more than 80% terrestrial plants to form a mutually beneficial symbionts,combine with host plants to form large filament network,enhance absorption ability of host plants to mineral elements in soil, improve resistance to heavy metals and nuclide.In this study,the potted Sorghum halpenses used as phytoreme-diation materials were contaminated with cesium and inoculat-ed with arbuscular mycorrhizal fungi,to analyse the effects of different arbuscular mycorrhizal fungi on rhizosphere soil enzyme activities, the absorption efficiency of mineral elements, the growth status of Sorghum halpenses, AsA-GSH cycle and the accumulation ability of Sorghum halpenses to cesium, to explore the application prospect of AMF in phytoremediation contaminated with cesium in soil, to provide theory basis for AMF-plantsymbionts reclamate cesium contaminated soil.The main results obtained in this research are as follows:The study of colonization rate and mycorrhizal dependency of different arbusculor mycorrhizal fungi on Sorghum haipense at soil contaminated with Cs.The colonization rates of selected five kinds of arbuscular mycorrhizal fungi(Glomus geosporum,G.mosseae,G.diapha num,G. versiforme and G. etunicatum) on Sorghum haipense root were significantly higher than control, G. diaphanum treatment was most significant reached 63.38%.Meanwhile mycorrhizal dependency of them were significantly higher than control,the most significant treatment was G.versiforme reached 156.32%, the order of other treatments were:G. mosseae> G. etunicatum>G. geosporum> G. diaphanum,which demonstrated Sorghum haipense was mycorrhizal dependency plants.2 The effects of different arbuscular mycorrhizal fungi(AMF)on soil fertility, rhizosphere soil enzyme activities and biomass Sorghum laipense contaminated with Cs.The inoculation AMF promoted the acidic phosphatase,invertase and catalase activity in rhizosphere soil under Cs stress, G. diaphanum G. mosseae and G. etunicatum treatment respectively, were most significantly 7.58,2.26 and 1.12 times than control. On the contrary, moculation AMF significantly inhibited the urease activity, the inhibit-ion of G. geosporum treatment was most significant and the enzymatic activity was 84.21% of control. On the other hand, inoculation AMF enhanced the absorption ability of Sorghum haipense to ammonium nitrogen, effective phosphorus and organic matter, but also the growth of Sorghum haipense was improved, the largest amplification of leaves, stems dry weight and root length respectively was 43.93%,74.28% and 92.60% compared to control, G. diaphanum, G. versiforme and G. etunicatum treatment were showed respectively, G.mosseae treatment significantly enhanced dry weight of the underground part, plant height and stem diameter, respectively was 2.02,1.65 and 1.33 times than control. Regression analysis between root length, plant height and rhizosphere soil enzyme activities demonstrated that the degree of correlation between root length and rhizosphere soil enzyme was higher han plant height.It demonstrated that inoculation AMF enhanced rhizosphere enzyme activities of Sorghum haipense,and then promoted the absorption ability of Sorghum haipense to mineral elements in soil, increased the biomass of host plants. 3 The effects of AMF on AsA-GSH cycle of Sorghum haipense under Cs stressInoculation AMF increased the content of AsA and GSH,decreased the content of DHA and GSSG.increased AsA/DHA and GSH/GSSG ratio in roots and leaves of Sorghum haipense under Cs stress. Meanwhile, five different inoculation AMF enhanced antioxidant enzymatic activities of Sorghum haipense, G. mosseae treatment significantly increased the enzyme activities of APX, DHAR, and GR of Sorghum haipense in roots was 2.34,3.50 and 3.78 times than control respectively, and G. versiforme treatment significantly improved VIDHAR activity; In addition, G. geosporum treatment significantly increased MDHAR and GR enzyme activities of Sorghum haipense in leaves, and the effects of inoculation G. versiforme and G. mosseae on APX and DHAR enzyme activities were most significant respectively.It demonstrated that inoculation AMF increased antioxidant enzyme activities of Sorghum haipense in roots and leaves under cesium stress, promoted the regeneration of antioxidants AsA and GSH, thus enhanced the ability of Sorghum haipense to resist cesium stress.The correlation analysis between mycorrhizal colonization and AsA-GSH cycle of Sorghum haipense in roots and leaves demonstrated that mycorrhizal colonization and antioxidant(AsA and GSH), antioxidant enzymes(APX、 VIDHAR、DHAR and GR),oxidized and reduced value AsA/DHA、 GSH/GSSG were positively correlated,but negative correlation between nycorrhizal colonization and GSSG,DHA. It demonstrated that inocul-ation AMF enhanced the antioxidant capacity of Sorghum haipense, raised the ability of Sorghum haipense to resist cesium stress.The appraisal of repair benefit of different arbusculor mycorrhizal fungi on Sorghum haipense in soil contaminated with CsInoculation AMF enhanced the ability of Sorghum haipense to enrich Cs,significantly increased Cs content in overground and underg-round part, leaves had more stronger ability than roots to accumulate Cs,promoted more Cs to enrich in overground part of Sorghum haipense, decreased Cs residue in soil,and Cs enrichment factor in overground and underground part of Sorghum haipense was higher than control, the enrichment factor of G. versiforme and G. mosseae was highest among treatments,respectively, was 10.41 and 2.3,the transfer factor of G. iiaphanum was 5.03 was most among all treatments.The correlation analysis demonstrated that colonization rate and Cs content in averground and underground part of Sorghum haipense was positively correlated, but Cs content in soil was negatively correlated,rhizosphere soil enzymes activities and Cs enrichment factor in overground and underground part were positively correlated, which demonstrated that inoculation AMF increased rhizosphere soil enzymes activities of Sorghum haipense under Cs stress, and promoted absorption, migration and transfer ability of Sorghum haipense to Cs. However, there was negative correlation between enrichment factor in aboveground and underground and urease, the correlation coefficient was-0.97* and-0.98*, it demonstrated that the inhibition of ceasium to urease was higher than the promotion of AMF to urease activities possibly inoculated with AMF, therefore urease was used as a physiological index to measure the pollution degree in contaminated with soil.