Effects Of AM Fungi And Their Interactions With Phosphatesolubilizing Bacteria On Phosphorus Absorption Of Camellia Oleifera

In this study,Camellia oleifera Abel,Claroideogolmus etuicatum,and Bacillus aryabhattai were chosen as experimental materials.On the one hand,through pot experiments,the effects of AM fungi on the growth,photosynthesis,and soil phosphorus forms of C.oleifera under different concentrations of inorganic phosphorus were explored,and the mechanism by which AM fungi promoted the absorption of inorganic phosphorus in C.oleifera was revealed;On the other hand,through a three-compartment net culture system,the interaction of AM fungi and phosphate-dissolving bacteria on soil organic phosphorus mineralization and C.oleifera phosphorus absorption was explored,and the interaction mechanism of AM fungi and phosphate-dissolving bacteria on C.oleifera organic phosphorus mineralization absorption was revealed.The main research results obtained are as follows:（1）Effects of AM fungi on the growth of C.oleiferaUnder low phosphorus(KH₂PO₄ 10 mg·kg^-1)level,inoculation of C.etuicatum significantly increased the ground diameter,aboveground dry weight,underground dry weight,root surface area and photochemical quantum efficiency.Under medium phosphorus(KH₂PO₄ 50 mg·kg^-1)Under the level of inoculation,C.etuicatum significantly increased the ground diameter of the C.oleifera the dry weight of the above ground,the average root diameter,the root projected area,the chlorophyll content,the net photosynthetic rate,and the photochemical quantum efficiency.Under high phosphorus(KH₂PO₄ 100 mg·kg^-1)At a horizontal level,inoculation of C.etuicatum significantly increased the underground dry weight,root volume,root surface area,chlorophyll content and net photosynthetic rate of C.oleifera It shows that AM fungi can expand the absorption area of the root system when the phosphorus is low,increase the chlorophyll content of the leaves of the C.oleifera,which is conducive to the photosynthesis of the C.oleifera,thereby promoting the growth of the C.oleifera and increasing the biomass of the C.oleifera.（2）Effects of AM fungi on the phosphorus concentration of C.oleifera and soil phosphorus formsUnder low phosphorus levels,inoculation with C.etuicatum significantly reduced the content of Fe-P,Ca-P and OP;under medium phosphorus levels,inoculation with C.etuicatum significantly reduced the content of Fe-P and Ca-P;under high phosphorus levels,inoculation C.etuicatum significantly reduces the content of Fe-P,Ca-P and OP.Under different KH₂PO₄ concentrations,inoculation with C.etuicatum significantly increased the phosphorus concentration in the shoots and roots of C.oleifera It shows that AM fungi can increase the absorption efficiency of available phosphorus in the C.oleifera,and at the same time can convert part of the insoluble phosphorus into the available phosphorus form of the plant,thereby increasing the phosphorus content of the C.oleifera.（3）The effect of AM fungi on the expression of Pht1;1 gene in C.oleiferaUnder low phosphorus levels,inoculation with C.etuicatum increased the expression of Pht1;1 gene in C.oleifera roots,while at medium phosphorus levels,inoculation with C.etuicatum significantly reduced the expression of Pht1;1 gene in C.oleiferaroots.It shows that AM fungi can increase the expression of the phosphorus transporter gene in the root system of C.oleifera within a certain range of phosphorus supply intensity,and inhibit the expression of the Pht1;1 gene in the root system when it exceeds this range.（4）The interaction of AM fungi and phosphate solubilizing bacteria on the growth of C.oleifera and the phosphorus content of plantsAt the levels of P0(C₆H₁₆Ca₂₄O₂₄P₆ 0 mg·kg^-1)and P75(C₆H₁₆Ca₂₄O₂₄P₆ 75mg·kg^-1),single inoculation of C.etuicatum significantly increased the ground diameter（30.48%,14.69%）and the aboveground phosphorus concentration（7.06%,7.40%）and root phosphorus concentration（1.58%,6.00%）;single inoculation of phosphate solubilizing bacteria treatment significantly increased the ground diameter（31.94%,18.19%）,aboveground phosphorus concentration（13.50%,9.94%）and root phosphorus concentration（2.64%,3.25%）;double inoculation treatment significantly increased plant height（21.11%,18.41%）,ground diameter（39.60%,39.36%）,aboveground phosphorus concentration（15.14%,13.49%）and root phosphorus concentration（3.21%,10.24%）.It shows that the interaction of AM fungi and phosphate-dissolving bacteria can increase the phosphorus concentration on the ground and the root system of C.oleifera,and the growth-promoting effect on C.oleifera is stronger than that of single inoculation.（5）The interaction of AM fungi and phosphate solubilizing bacteria on substrate phosphatase activity,phytase activity and phosphorus formAt P0 and P75 levels,single inoculation of C.etuicatum significantly increased the substrate acid phosphatase activity（0.06%,2.35%）and phytase activity（1.85%,35.55%）;the monophosphate solubilizing bacteria significantly increased the substrate acid phosphate enzyme activity（6.08%,6.83%）,phytase activity（45.50%,47.04%）;double inoculation significantly increased substrate acid phosphatase activity（6.90%,5.81%）,alkaline phosphatase activity（5.32%,5.74%）and phytase activity（49.75%,63.12%）.In addition,single inoculation of C.etuicatum increased the Sonic-Po content and HCl-P content of the hyphae compartment,and reduced the Na OH-Po content;double inoculation increased the content of H₂O-P,Na HCO₃-Pi and Na HCO₃-Po in the hyphae compartment,Sonic-Pi content,Sonic-Po content and HCl-P content.It shows that AM fungus and phosphate solubilizing bacteria can secrete more phosphatase to promote organophosphate in the matrix to improve the effectiveness of phosphorus in the matrix.