| Cunninghamia lanceolata is the most important timber tree species in Fujian and even the southern area,with good ecological and economic benefits.However,continuous planted artificial pure forest of Cunninghamia lanceolata will cause soil degradation,and land productivity declining.In the process of Cunninghamia lanceolata cultivation,the method to solve the problem of soil nutrient deficiencies through fertilizer will not only pollute the environment and break the ecological balance,but also the season utilization rate of fertilizer conducted in the plants is quite low.Researches about the phosphorus,potassium microbial transformation of soil insoluble phosphorus and potassium to improve the soil fertility and further contribute to the Cunninghamia lanceolata growth and sustainable development of Cunninghamia lanceolata artificial forest has important practical significance.Therefore the research adopted different ages of Cunninghamia lanceolata root soil in Huanxi forest farm and Xidong forest farm in Fujian area as research objects,selected high effective bacterial strains of phosphorus,potassium microbial through static qualitative tests and shaking bottle quantitative tests;analyzed with 16S rDNA through the observation of the shape features of bacterial colony and bacterial strains,classified and identified on the separated high efficient phosphorus,potassium bacteria;meanwhile optimized the nutrient media components and fermentation conditions in the case of shaking cultivation on bacterial strains,and determined the best cultivation plan.The research mainly obtained following results:The quantity range of Cunninghamia lanceolata root inorganic phosphorus in rhizosphere bacteria is 2.62～8.45×105 cfu/g;the quantity range of Cunninghamia lanceolata root organic phosphorus bacteria in rhizosphere bacteria is 1.31～5.03×105 cfu/g;the quantity and variety of the root phosphorus in Huanxi forest farm is beyond that of Xidong forest farm.Through the tests on the separated 25 pcs of inorganic phosphorus and 20 pcs of organic phosphorus by cultivation of phosphate dissolving ring method and liquid shaking,results showed that:(1)the diameter of transparent circle of inorganic phosphorus bacteria is between 5.06mm～12.28mm,the changing range of the transparent circle diameter D and the bacterial colony is 1.08～3.05;the range of liquid dissolved phosphorus is 6.21μg/ml～238.08μg/ml;the bacterial liquid pH is between 3.90～6.81,the ability of inorganic phosphorus bacteria dissolved and the pH value of the solution existed remarkable negative correlation(P<0.01,R2=-0.739);among which the bacterial strain WP1(238.08μg/ml)and WP10(213.05μg/ml)has best effect of phosphorus solution,with the identification of 16S rDNA they are both Acinetobacter.(2)The phosphorus solution bacterial circle diameter of organic phosphorus is between 3.69mm～9.65mm,the changing range of the ration between the solubilizing circle diameter(D)and the bacterial colony diameter(d)is 1.08～2.26;the range of liquid phosphate is 4.78μg/ml～15.04μg/ml;the pH of bacterial liquid is between 6.58～7.42,the quantity of organic phosphorus bacterial strain and pH value of solution has no correlation(P>0.05,R2=0.170);among which the YP9 bacterial strain(15.04μg/ml)has best effect of phosphorus dissolution;with the identification of 16S rDNA it’s Klebsiella.Using the Portland medium and liquid shake cultivation to test on the separated 20 pcs of potassium bacteria,results showed that the content range of soluble potassium in the solution of strains is 38.42μg/ml～81.06μg/ml,there are 65%strains showing the capacity of potassium solution,the liquid soluble potassium content range is 52.17μg/ml～81.06μg/ml,the potassium solving rate in the strains is between 3.29%～60.48%;pH value of liquid bacterial is between 4.12～6.97,the releasing capacity of mucilaginous potassium has no correlation with pH value of solution(P>0.05,R2=0.105);among which the bacterial strain JK13(81.06μg/ml,60.48%)and JK2(73.93μg/ml,46.37%)has the best potassium solution ability,with the identification of 16S rDNA they are Bacillus(JK13)and Methylobacterium(JK2).Determine the optimization range of cultivating conditions of all strains through single factors experiments,and combine the orthogonal design test to obtain the best shaking bottle cultivating conditions plan for the bacteria strains,the results showed that:(1)the most suitable carbon source of WP1 is 1.0%concentration of glucose,the most suitable nitrogen source is 1.50%concentration of yeast power,the best cultivating plan:pH 7.5,loaded liquid 20ml/100ml,vaccination volume 5%,temperature 35℃;the bacteria growth after optimization improved 15.02%than the situation without optimization.(2)the most suitable carbon source of WP10 is 0.5%concentration of maltose,the most suitable nitrogen source is 1.50%concentration of yeast power,the best cultivating plan:pH 7.5,loaded liquid 30ml/100ml,vaccination volume 5%,temperature 35℃;the bacteria growth after optimization improved 10.24%than the situation without optimization.(3)the most suitable carbon source of YP9 is 0.5%concentration of glucose,the most suitable nitrogen source is 1.25%concentration of yeast power,the best cultivating plan:pH 6,loaded liquid 20ml/100ml,vaccination volume 7%,temperature 35℃;the bacteria growth after optimization improved 31.02%than the situation without optimization.(4)the most suitable carbon source of JK13 is 0.5%concentration of mannitol,the most suitable nitrogen source is 1.0%concentration of yeast power,the best cultivating plan:pH 9,loaded liquid 3 0ml/100ml,vaccination volume 1%,temperature 35℃;the bacteria growth after optimization improved 57.56%than the situation without optimization. |
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