| Phosphorus is one of the necessary factors in the life of the plant. Most of soil in our land are P deficiency, mainly about 95% phosphorus in soil cannot be directly used by plant. Although applying P fertilizer in the soil is the main way to raise the amoun tof available P, the applied P fertilizer is ofter converted into unavailable P by combining with Ca3+,Fe3+ and Al3+, which lose efficacy. In usual, the utilization ratio of P fertilizer only ranges from50% to 25%, As the result, it is important to convert insoluble P into soluble P and to release P from lecithin. Phosphate solubilizing microorganisms which can transform unsoluble phosphate into available forms, and thus not only improve the phosphorus nutrition and the growth of plants, but also take an important part in phosphorus cycling in calcareous soil and the ability of the soil to supply P. In this study, we collected sample soil from the advantage plants pewterwort of the wastelands of mine tailings in tongling city, anhui province. The screenings were done using the traditional method of dilution and besmear flat, incubating in 29℃. Many Phosphate solubilizing strains were separated through preliminary screening on the NBRIP solid medium, then rescreening was done using broth assay method, At last, B25 and F4 were selected which present the best ability of phosphorus solubilization, morethen, F4 is superior to B25, the best ability of phosphorus solubilization can last for a long time.Fungi F4 and bacteria B25 were identified by the methods of molecular biological, morphological were observated by scanning electon microsope. Extracted the genomic DNA of the two strains, then amplificated the 18Sr DNA and 16Sr DNA, through cloning and sequencing the genetic sequences were contrasted the homology in GenBank. Homological analysis showed that the gene sequence of B25 had a high homology to GU297610 (Bacillus anthracis strain U13), EF062509 (Bacillus sp. MCCB 101) and AM778997 (Bacillus thuringiensis 16SrRNA gene and 16S-23S IGS), the gene sequence of B25 had a high homology to AY030322,DQ278883,M55639 (Aureobasidium pullulans), the similarity were up to 99%, As a result, we come to a conclusion Fungi F4 is Aureobasidium pullulans, bacteria B25 belongs to Bacillus.Study the relationship between the pH value of medium and the growth of phosphate solubilizing microorganisms for the ability of phosphorus solubilization. the result showed that, In the process of cultivation, the ability of phosphorus solubilization and pH value of medium had a certain negative correlation, morethen, Fungi F4 showed stronger than bacteria B25. There was a significant positive correlation between the ability of phosphorus solubilization of fungi F4 and the growth bacteria, however, bacteria B25 was not. Research the influence which different environmental factors imposed on the the ability of phosphorus solubilization. Results showed that the best carbon was starch, the best cultivation temperature is 30℃, the best initial pH value is 6.0 for fungi F4; corresponded to bacteria B25 were glucose,30℃and 7.0.In pot experiments, the height, dry weight, total P and total N of the tested plants had significant difference between CK and the treatments with the addition of phosphate solubilizing microorganisms strains after the growth of 90 days Meanwhile, we followed the changes of the total content of heavy metals in plants and the content of the effective heavy metal in the tailings, The results showed that there was also significant difference between CK and the treatments, in a certain extent, this action improve the adsorption ability of plants for heavy metals and the levels of the effective heavy metals of tailings, but this kind of influence did not have a certain regularity, what is more, some heavy metal elements appeared the release phenomenon. |
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