The Components Of The Bacteria And Microbial Phosphorus In Red Soils Of China Applied The Technique Of Aqueous Two-Phase Partitioning

Influenced by the subtropical climate and unreasonable use in deeply weathering red soils, the nutrient content is lower, especially the validity of phosphorus. The microorganisms could immobilize and transform organic and inorganic forms phosphorus, make them become one of the main sources to provide phosphorus for the plant growth. More and more attention has emphasized on how to improve availability of this part phosphorus.The technique of aqueous two-phase partitioning (A2PP) has been considered as a useful tool to separate and purify cell, virus, macromolecule and applied to biochemistry, cytobiology and other relevant fields. There is few reports in soil field up to date. This experiment was commixed the soil, Dowex resin, sodium cholate and glassware. The soil solution was passed through a 20-30 μ m filter paper by vacuum extracting. The proper volume liquids were taken out and added into the PEG/Dextran system for purification. The bacteria biomass and the component of bacteria phosphorus were determined. The applicability of A2PP in the soil field and the relationship with soil phosphorus and soil physical- chemical character were studied, so as to confirm the main contributor of soil microbial phosphorus components in the subtropical area. The main results showed:1. The soil bacteria was well dispersed after the Dowex resin, sodium cholate, glassware and soils were placed into a flask and the suspension was shaken for 2h .The dispersion of bacteria was between 0.41⁰.60 and it was different for different parent material, with the order of sandstone > granite > Q2.2. The experiments proved that A2PP could well purify the soil bacteria.(1) In the two phases, the soil bacteria after purified existed in the top phase, and more than 63⁷8% of soil bacteria number added were obtained respectively.(2) Under the fluorescence microscope , the soil bacteria was tied with soil clay and organic matter, but A2PP could get more purer bacteria.(3)The ratio of bacteria extraction was between 0.31 to 0.48, and it was different for different parent material, with the order of sandstone > granite > Q₂。3. A2PP was applied to the following different researches.(1) For the typical six red soils derived from different parent material, the bacteria forms were mostly small ball, small bacilli.(2)The microbial phosphorus(MP)was determined. All the soils was mainly made up of the fungal phosphorus (FP) for the vegetable garden soil, woodland except of thetea garden soil, and the ratio of fungal P to microbial P was woodland > vegetation > tea garden soil.(3) Fungal phosphorus was tested the active participator during the process of immobilizing and transforming of P for the subtropical red soils in the microbial P components. Fungal phosphorus had a significant positive correlation with microbial phosphorus and organic phosphorus extracted by H2O, and the correlation coefficients were beyond 0.92 (n=6). Fungal still had positive correlation with soil available phosphorus, organic matter, organic phosphorus sum, organic phosphorus extracted by NaOH, inorganic phosphorus extracted by NaHC03? and total phosphorus. In addition, bacteria phosphorus had positive correlation with organic matter. Fungal still had correlation with microbial phosphorus, organic phosphorus extracted by NaOH and organic phosphorus sum.