The Selective Breeding Of High Efficient Phosphate-dissolving Aspergillus Niger Strain By ARTP And Its Characteristic Study

In this paper,Aspergillus niger XJ was mutagenized by ARTP.The positive mutant strains were screened by plate screening,shaking flask screening and genetic stability test.Then the acid-producing ability,environmental tolerance,bacteriostatic and growth-promotion were compared by the original strain and the mutant strains to investigate the Phosphorus-dissolving characteristics of the positive mutant strain.The results were shown as follows:1.Four good genetic stability strains XJ90-32,XJ120-12,XJ120-31 and XJ180-22 was screened by plate screening,liquid shaking flask screening and 10 generations of culture.Compared with the original strains,their phosphate-dissolving ability were increased by 50.3%?57.5%?55.9% and 61.4%,respectively.2.The results of acid production showed that the original strain and positive mutant XJ120-31 only secreted oxalic acid,but XJ90-32 and XJ180-22 also secreted citric acid,and XJ120-12 also secreted citric acid and succinic acid.For indole acetic acid,XJ120-12 increased by 10.5% compared with the original strain.3.The results of environmental tolerance showed that the optimum carbon and nitrogen sources for strains were glucose and ammonium sulfate,which were stage-tolerant to high concentration of glucose.When the ammonium sulfate concentration exceeded 0.5%,NaCl concentration exceeded 1%,temperature exceeded 35 ?,and pH exceeded 7,the ability of strains to phosphate-dissolving began to decline,and the ability to phosphorus-releasing in different insoluble phosphate media was the best.4.The pot experiment of peanut showed that inoculation of Aspergillus niger strains could promote peanut growth and increase soil available phosphorus content,of which XJ120-12 was the most effective.Compared with CK,the stem length,root length,fresh weight,dry weight,chlorophyll content and total protein content of peanut treated with XJ120-12 increased by 68.7%,132.7%,67.7%,117.2%,12%,49.5% respectively,and the soil available phosphorus content increased by 168.2%.The results of bacteriostasis experiments showed that XJ120-12 had the best bacteriostasis against Alternaria and Phytophthora tobacco,and XJ90-32 had the best bacteriostasis against three plant pathogenic bacteria.