| Phosphorus applied to soil is quickly fixed into insoluble phosphates,which reduces the available phosphorus content in soil.Phosphate solubilizing microorganism can dissolve insoluble phosphates into soluble form for plant absorption and utilization.Although scientists around the world have isolated and screened a large number of phosphate solubilizing microorganisms,different microorganisms have different phosphate solubilizing ability,suitable growth conditions and promoting effects on crops.Therefore,more kinds of phosphate solubilizing microorganisms with wide adaptability and beneficial to crop growth need to be developed to meet agricultural needs.In this study,phosphate solubilizing microorganism was screened from the rhizosphere soil of Tomato in solar greenhouse.The factors affecting the growth and metabolism,the ability to dissolve different phosphates,the viability in different soils and the effect on crop growth of the phosphate solubilizing microorganism were studied in order to provide a theoretical basis for the rational application and the full play of phosphate solubilizing effect of it.The main results are as follows:?1?A fungus with high phosphate solubilizing capacity was screened out,which was identified as Penicillium oxalicum and named PSF1.?2?Penicillium oxalicum PSF1 can utilize various carbon sources such as glucose,sucrose,lactose,galactose,soluble starch and nitrogen sources such as ammonium nitrogen,nitrate nitrogen,amide nitrogen.C/N 10:1 60:1,initial p H 7 10 and culture temperature 20 35? are suitable for the growth and metabolism of strain PSF1,which can also maintain high phosphate solubilizing capacity.?3?The phosphate solubilizing capacity of Penicillium oxalicum PSF1 to tricalcium phosphate and phosphate rock powder are 869.62 and 233.56 mg·L-1 respectively,and that to iron phosphate and aluminium phosphate are 28.42 and 44.77 mg·L-1 respectively.There are very significant negative correlations between the phosphate solubilizing capacity of strain PSF1 to tricalcium phosphate,phosphate rock powder,iron phosphate and the p H of culture mediums but no significant correlation between the solubilizing capacity of strain PSF1 to aluminum phosphate and the p H of culture medium.?4?Penicillium oxalicum PSF1 can grow normally and improve available phosphorus content in brown earth,black soil and cinnamon soil.Strain PSF1 can grow normally and exert phosphate solubilizing capacity under the conditions of soil relative water content 60% 90%,culture temperature 20 30?.Strain PSF1 grew best when glucose was the carbon source and grew better under soil sterilization condition.?5?In pot experiment,the content of soil available phosphorus increased by 4.07% 31.57% in inoculation treatments compared with that in non-inoculation treatments when Brassica Napus was harvested.The fresh and dry weight of Brassica Napus increased by 6.51% 26.84% and 3.48% 27.89% respectively,N,P,K content increased by 1.80% 17.26%,9.02% 32.52%,6.18% 21.35% respectively,and chlorophyll content increased by 3.85% 19.91% in inoculation treatments compared with that in non-inoculation treatments.?6?The number of strain PSF1 in organic material treatments was higher than that in chemical fertilizer treatment.The growth of PSF1 was the best when chicken manure was used as organic carrier.The number of strain PSF1 in soil under high inoculation quantity was higher than that under low inoculation quantity. |
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