草地早熟禾根际固氮菌的培养

Culture condition of nitrogen fixation strains isolated from rhizosphere of Kentucky bluegrass

从草地早熟禾(Poa pratensis)根际土壤中筛选得到8株具有较高固氮、溶磷能力的高效固氮菌菌株,研究其培养条件及典型生长曲线。结果表明,本研究筛选得到的菌株对温度的适应范围比较广,在20~40℃的环境条件下可以正常完成新陈代谢及繁殖发育,最适生长温度为25℃;菌株在中性或偏碱性的条件下生长较好,最适生长初始pH值为7.0~7.5;菌株N4、N5、N10、N16、N17、N20的最佳通气量为220mL,菌株N2、N14的最佳通气量分别为200及100mL。根据所得数据,进一步试验,得到了固氮菌菌株的典型生长曲线,绝大部分的菌株在培养2h后就进入了对数生长期,不同的菌株进入延时期、对数期、稳定期、衰亡期的时间及持续时间也不同。

Culture conditions and typical growth curve of eight nitrogen-fixing bacteria strains with strong ability of nitrogenase activity and the solubilizing phosphorus capability isolated from Kentucky bluegrass rhizosphere soil samples were studied.The results showed that the temperature adaptation scope of strains was wide and strains could grow well between 20~40℃,with the optimum growth temperature of 25℃.The nitrogen fixation strains could grow well in a neutral or slightly alkaline pH condition,with the optimum initial pH range of 7.0to 7.5.The optimum ventilation volume of strain N4,N5,N10,N16,N17and N20 were 220mL,and the optimum ventilation volume of strain N2and N14were 200and 100mL.Based on the above results,the typical nitrogen-fixing bacteria strains growth curves were determined.Most of the strains entered the logarithmic phase after 2h.Different strains started the lag phase,the logarithmic phase,the stationary phase and the declining phase at different culture time.