Effects Of Polyphosphate Actinomycetes (YIM A116) On Soil Phosphorus Forms And Plant Growth Under Phosphorus-enriched Soil In Central Yunnan

The central of Yunnan has large areas of phosphorus-enriched soil,and phosphorus loss with runoff was serious.Control of phosphorus loss in phosphorus-enriched soil is one of the key measures of eutrophication control of lake waterbody.Plants and soil microorganism integrated control is considered to be the most environmental protection measures to reduce the risk of phosphorus loss.In this paper,to explore the effects of polyphosphate actinomycetes adding on soil phosphorus fractions and the growth of plants,4 treatments of soil treatments(sterilization soil,original soil.sterilization soil + polyphosphate actinomycetes,original soil + polyphosphate actinomycetes),3 treatments of carbon additon concentrations(0,0.5 mgC/g soil,2.5mgC/g soil),2 treatments of water treatments(normal water content、10%PEG 6000),2 treatments of plant soecies(Medicago sativa L.,Lolium perenne L.)were designed,and soil phosphorus fractions,soil physical and chemical properties,plant photosynthetic indices,plant physiological and biochemical indices,and plant growth index were analyzed.The main research results were as follows:(1)Effects of polyphosphate actinomycetes adding on soil physic-chemical propertiesAfter adding polyphosphate actinomycetes,the contents of Al-P and dissolved total phosphate in soil were decreased significantly(decreased by 20.96%and 20.65%respectively),and soil available phosphorus content was significantly increased by 38.23%;Soil available phosphorus content was increased by 4.7%after adding 2.5 mg C/g soil concentration of carbon source.For original soil,soil available phosphorus content was increased by 3.4%after adding phosphorus actinomycetes.The soil contents of TP、Fe-P、Ca-P and O-P have no significant difference compared with sterilization soil.After adding polyphosphate actinomycetes,the content of polysaccharide is significantly increased,and the pH is significantly lower.There is no significant difference for available nitrogen and dissolved total nitrogen between soil of adding polyphosphate actinomycetes and sterilization soil.(2)Effects of polyphosphate actinomycetes adding on plant growthUnder phosphorus-enriched soil,maximum net photosynthetic rate,transpiration rate,and stomatal conductance significantly improves after adding polyphosphate actinomycetes.The maximum net photosynthetic rate,transpiration rate,stomatal conductance increase by 18.85%,46.98%,55.69%for L.perenne,and 57.29%,79.83%,54.19%for M.sativa,respectively.Moreover,sucrose phosphate synthase(SPS),nitrate reductase(NR),acid phosphatase(ACP)activities of plant increased significantly after adding polyphosphate actinomycetes.For biomass,the plant biomass increased significantly after adding polyphosphate actinomycetes.(3)Response of plant under drought stress after adding polyphosphate actinomycetesUnder soil drought stress,after adding phosphorus actinomycetes,the content of proline significant increased by 10%and 19.2%respectively for L.perenne and M.sativa after adding polyphosphate actinomycetes.Antioxidant enzyme activities also significantly increased.However,no significant difference for superoxide dismutase(T-SOD)activity was not found.In total,though plant biomass decreased under drought stress,adding of polyphosphate actinomycetes would effectively alleviate drought effect.These results showed that polyphosphate actinomycetes would influence soil physical and chemical properties,especially soil phosphorus fractions,moreover,it also influence plant photosynthesis and physiological and biochemical indices.As the result,plant nutrition condition and ability of plants to resist stress were improved,and the plant biomass increased,leading to reduce the risk of phosphorus loss.