Effects Of Nitrogen Application And Inoculating Ectomycorrhizal Fungi On Carbons Sequestration Of Pinus Tabulaeformis

Pinus tabulaeformis, dependent on ectomycorrhizal fungi （ECMF）, is one of the mostimportant species in the boreal forest ecosystem. In this study, Pot test of P. tabulaeformisinoculated with ectomycorrhizal fungi were used collectively at four N levels (0,4.5,9,18mg·L^-1NH4NO3), In order to study the effect of Aminita vaginata, Suillus lactifluus and S.tomentosus respectively at different N levels on growth, photosynthetic pigment content,photosynthetic characteristics, chlorophyll fluorescence parameters and carbohydrateaccumulation and distribution of P. tabulaeformis. At the times, the above three kinds ofECM fungi were studied in different ratio of carbon to nitrogen by adding nitrogen to changein pure culture. Growth, dry matter accumulation, respiratory release the amount of CO2aswell as the secretion of nitrate reductase and urease were measured.The results are as follows:1. Effects of different ratio of carbon to nitrogen on growth, respiration and thesecretion of enzyme of ECM FungiEffects of different ratio of carbon to nitrogen on the diameter of the colony and themycelium biomass of ectomycorrhizal fungi mycelium were very different with differentfungi species. Overall, grow of ectomycorrhizal fungi in the C: N20:1medium was the best,in C: N10:1and C: N40:1medium growthes were poor. SL is the fastest, AV followed, STslowest. Respiratory release CO2of three fungi were like this: SL is the biggest, AV followed,ST least. Respiratory release CO2of SL and ST in the C: N20:1medium was significantlygreater than the other two carbon-nitrogen ratio medium. Amount of respiratory release CO2of AV in three different ratio of carbon to nitrogen medium had no significant difference.Different species of nitrate reductase and urease activity varied widely, showing the AVhighest, the SL followed, ST lowest. The activitives of both enzymes of SL in differentcarbon to nitrogen ratio all had following rules:[C: N20:1]>[C: N40:1]>[C: N10:1]. Theactivitives of both enzymes of AV in the C: N20:1medium was significantly larger than theother two carbon-nitrogen ratio medium.2. Effects of nitrogen and ECM fungi on growth and photosynthesis of P.tabulaeformisAt the same N level, growth and biomass of Pinus tabulaeformis seedlings inoculated with ectomycorrhizal fungi were higher than the uninoculated, and seedlings inoculated withA. vaginata were the best while those with S. lactifluus and S. tomentosus showed nosignificant difference. Photosynthetic pigment content, net photosynthetic rate, stomatalconductance, transpiration rate, Fv/Fm as while as ΦPSII of Pinus tabulaeformis seedlingsinoculated with ectomycorrhizal fungi were increased, and net photosynthetic rate ofseedlings inoculated with A. vaginata was very significantly improved. These parameterswere all influnced by the nitrogen concentration, increased before a decrease as the nitrogenconcentration increased，with a peak at9mg·L^-1. Nitrogen concentration and ectomycorrhizalfungi had an interactive effect on the growth and photosynthetic characteristics of Pinustabulaeformis seedlings, and the inoculation of ectomycorrhizal fungi would benefit them at arespect of growth, with a optimal condition of the combination of A. vaginata and an amountof9mg·L^-1nitrogen concentration.3. Effects of nitrogen and ECM fungi on non-structural carbohydrate of P.tabulaeformisAt the same N level, Percentage of reducing sugar and soluble sugar in roots, stems andconifer of P. tabulaeformis seedlings inoculated with ectomycorrhizal fungi all had followingrules: AV> ST> SL>CK. However, Percentage of starch in these parts had no the coincidentrules. Percentage of reducing sugar and soluble sugar content of the whole P. tabulaeformisseedling inoculated with ectomycorrhizal fungi varied widely, showing the AV highest andCK lowest. Percentage of starch content of the whole seedling had no significant difference.Non-structural carbohydrate accumulation of the whole seedling inoculated with AV wasvery significantly improved. These parameters were all influnced by the nitrogenconcentration, increased before a decrease as the nitrogen concentration increased，with apeak at9mg·L^-1. Each treatment seedlings’ NSC allocation in different organ had nosignificant difference, overall showing up to NSC allocation in roots most, followed byconifer, stems least.