石灰性土壤中解磷优势菌的筛选研究

从石灰性土壤作物根际土样筛选出2株具有较强解P能力的优势菌株“B2”和“B67”,平板培养溶P圈D/d值分别为5.1和3·8,液体摇床培养过程中产生苹果酸、丙二酸、草酸和乳酸等多种有机酸,产酸总量分别为对照的28·25和19.78倍,pH分别较对照下降2.3和1.1,将“B2”和“B67”的培养液分别接种到4个不同地区土壤中恒温恒湿培养20d后测定结果表明,所有土壤中速效磷含量均有所提高,且接种“B2”处理分别为对照的2.64、3.04、1.71和2.20倍,接种“B67”处理分别为对照的2.12、1.90、1.35和1.78倍,且发现其溶P效果和土壤磷酸酶活性与有效活菌数变化趋势基本一致。

Selection of dominant bacteria for phosphate liberation in calcareous soil

B2 and B67 were identified as two best bacteria to promote phosphate liberation from crops rhizosphere.During incubation in culture media with B2 and B67,the phosphate dissolved circles in plate culture,i.e.D/d values,are 5.1 and 3.8 respectively for B2 and B67.More than one kind of organic acids,including malic acid,malonic acid,oxalic acid and lactic acid,are produced and the total amount of acid is 28.25 and 19.78 times of control,respectively.Further the pH of culture media decline 2.3 and 1.1 units,respectively.When four soil samples,collected from different areas,are incubated with the above culture media for 20 days under the conditions of constant temperature and humidity,available phosphate in four soil samples is enhanced by B2 and B67. Available phosphate contents are 2.64,3.04,1.71 and 2.20 times of four control samples,respectively when the above four soil samples are incubated with B2;whereas available phosphate contents are 2.12,1.90,1.35 and 1.78 times of four control samples,respectively when the above four soil samples are incubated with B67.Also it is found that phosphate lyolysis is positively related to the available number of bacteria and phosphatase activity in soil.