西瓜根际土壤解磷芽孢杆菌的筛选及其解磷特性研究

Screening of Phosphorus-solubilizing Bacteria and Its Phosphate Solubilizing Characteristics in Rhizosphere Soil of Watermelon

解磷细菌能分解土壤中难溶的磷,可有效减少土壤磷的固定和缓解磷肥在土壤中利用率低的问题,因此为了获得有较强解磷性能的细菌,本研究通过平板溶磷圈法和钼锑抗比色法筛选出了一株具有较强解磷性能的细菌.通过对该菌株形态特征的观察和对其生理生化特征的分析以及对其16S rDNA基因序列的比对,确定该菌为枯草芽孢杆菌,并将其命名为GS032.该菌株有一定的产酸能力,在培养过程中可导致培养液的pH值产生较大幅度的下降;该菌的初始接种量越高,则最后培养液中所含有的可溶性磷就越高;当初始培养液的pH为5、接种菌量为8×107CFU和培养时间为3 d时,速效磷的含量最高,可达224 mg/L.

Phosphorus-solubilizing Bacteria can decompose the insoluble phosphorus in the soil,which can effectively reduce the fixation of soil phosphorus and alleviate the problem of low phosphorus fertilizer utilization in the soil. In our report,the Halo zone on agar plate and the molybdenum antimony resistance colorimetric were used to obtain the high-efficiency solubilizing-phosphate bacteria strain. The morphological characteristics,the physiological and biochemical characteristics,the 16 S rDNA gene sequence,were analyzed. The results showed that the bacteria strain is identified as Bacillus subtilis and named as GS032. The bacteria strain could secrete organic acids that cause the pH of the nutrient solution to drop significantly during culturing;the higher the initial inoculation amount,the higher the amount of soluble phosphorus contained in the final culture solution. When the initial culture medium pH was 5,the inoculation amount of bacteria was 8×107 cfu and the culture time was 3 days,the content of soluble phosphorus was the highest,which is 224 mg/L.