The Study Of High Dissolved Phosphorus Isolation Identification,Conditions Of Indoor Dissolved Phosphorus And Dissolved Phosphorus Effect In Rhizophere Soil Of Maize

Phosphate-solubilizing microorganisms is an important microorganisms involved in phosphorus cycling of soil, they are insoluble phosphorus can be transformed into effective phosphorus in soil. From rhizophere soil of maize in different farming areas of Chongqing have geted 10 of efficient phosphate-solubilizing strains by initial screening, and re-screening by more variety of insoluble phosphorus sources to have four strains, they are compatible with more variety of poorly soluble P sources, Then they were preliminary strain identification, indoor dissolved phosphorus conditions, phosphate solubilization capacity, dissolving characteristics, and to determine their influence on the growth of maize by the pot experiment, the following conclusions:1. Using the modified pvk method and dissolved phosphorus circle method to filter out the 56 relatively efficient phosphate-solubilizing strains (D/d≥1.5) from regions of the maize rhizosphere soil in Beibei, Fuling, Yunyang of Chongqing, the number of high efficiency soluble phosphorus strains found in different regions were various, They were:Beibei＞Yunyang＞Fuling, near the root zone is approximately equal to the far root zone. Among them, there were 28 (D/d≥2.0) by the shake flask cultures and useing of molybdenum antimony anti-colorimetric method to determine the soluble phosphorus content (available phosphorus and total phosphorus) to screene out of 10 efficient strains of phosphate solubilization.2. Analysis of plate screening (D/d) and shake flask screening (available phosphorus and total phosphorus), and between them there were significantly associated (r=0.402 and 0.531, p＜0.05), the results of two screening remained consistent. Plate screened of dissolved phosphorus in ring size (D) is more reactive phosphate-solubilizing strains of gastric acid secretion capacity, while plate screening (D/d) and colony (d) as a screening indicator in the large-scale screening strains, can speed up the potential of efficient strains of phosphate solubilization. Strains in shake flask screening soluble phosphorus content, which the difference between the available phosphorus in the amount of total phosphorus content, That is mainly reflected in the amount of strain on the P absorption.3. Compatible with the re-screening of a variety of insoluble phosphorus source characteristics of 10 bacteria to different insoluble phosphorus sources, various strains of dissolved phosphorus sources of different insoluble difference showing of Ca3(PO4)2＞Mixed insoluble phosphorus＞FePO4、AlPO4＞lecithin, Each of these strains FePO4 the difference compared to the rest of the phosphorus source, the dissolution of mixed phosphorus source is mainly reflected in the strain of Cas(PO4)2 dissolved.4. Comprehensive compatible with a variety of poorly soluble P sources screening analysis obtained, strains P1, P17, P35, P21 dissolution of Ca3(PO4)2 is relatively strong, the strains of P21, P17, P1 and P35 of AlPO4 the ability to dissolve relatively strong; P21, P17, P35, P22 and P1 of FePO4 the ability to dissolve relatively strong, P21, P1, P35, P17, for lecithin’s ability to dissolve relatively strong, P21, P35, P17, and P1 for the solubility of the mixed phosphorus source relatively strong; strain P1, P17, p21 and P35 together as shake flask screening from the insoluble phosphate source compatible with a variety of efficient strains of phosphate solubilization, where P21 strain in a variety of insoluble phosphate source filter has good phosphate solubilization performance.5. Dissolved phosphorus strains P1, P17, p21 and P35 for 22 kinds of physiological and biochemical identification showed that P1 is the cockroaches escherichia coli (Escherichia.blattae), P17 is acid producing Klebsiella (HP 1, Klebsiella oxytoca), p21 is fig shara coli (Serratia ficaria.plymuthica), P35 is cockroaches escherichia coli (E.blattae).6. Regulation of carbon and nitrogen sources (type and concentration level) experiment, each group of four strains of phosphate solubilization dissolved phosphorus and acid secretion have some impact. The best carbon source is glucose, ammonium sulfate is a relatively good source of nitrogen, In which P1, P21 are more suitable carbon source were 16g·L-1, P35 was 12g·L-1, P17 was 8g of L-1; P1 is more suitable nitrogen source was 0.4g L-1, P35 and P21 were 0.2 g·L-1, P17 was 0.6g·L-1.7.4 experimental strains are more sensitive to NaCl, the NaCl concentration of 0.1g·L-1, soluble phosphorus content of each strain is relatively small, about 2/3 of the remaining concentration of low NaCl concentration to inhibit the strain dissolved phosphorus, strains with salt tolerance, the relatively high NaCl concentration strain dissolved phosphorus content is still high, of which P17 strain is particularly prominent, higher than 50 ug·ml-1. Every strains to choose a more suitable NaCl concentration is 0.5g·L-8. The higher the amount of oxygen is four strains tested to give full play to the necessary conditions for phosphate solubilization capacity, of which P1, strain is a facultative aerobic bacteria, higher or lower oxygen levels with good phosphate solubilization the amount of P17, relatively small demand for oxygen, the oxygen level within a certain range, higher dissolved phosphorus. Every strains of the common choice is more suitable for medium volume is 20ml.9.4 phosphate solubilization agents inoculated in the normal growth of experimental soil could increase over time, agents in about 21 days when the maximum capacity of bacteria to the soil, followed by large-scale death and bacterial counts remained relativelylower level, accompanied by activation of the phosphorus in this process. Strains grown in sterile soil is relatively good, but not in sterilized soil select number of smaller bacteria strains in the two experiments in soil phosphate solubilization effect is similar to the experimental strains. 10. Without fertilizer, the bacterium was inoculated in the experimental soil with maize seedlings cultured 41 days after the maize seedling bio mass, soluble protein, soluble sugar content increases significantly higher than CK; while strengthening root activity; plants phosphorus utilization; four agents can promote the growth of maize seedlings and increase its resistance to a certain extent. Higher accumulation of growth of maize seedlings in sterile soil, not sterile soil inoculant its strong role in promoting.