东祁连山7种禾草根际溶磷菌筛选及其溶磷特性

Screening and characteristics of phosphate-solubilizing bacteria in rhizosphere of 7 grasses on eastern Qilian Mountains

采用PKO无机磷和蒙金娜有机磷选择性培养基,从东祁连山(甘肃省天祝县及周边地区)天然草地上的7种禾草根际分离出溶解无机磷菌株109株,溶解有机磷菌株143株。各菌株生长速度及形态特征差异较大。7种禾草根际溶解无机和有机磷菌株数量,除醉马草(Achnatherum inebrians)溶解无机磷呈根表土壤】根系表面】根内的分布趋势外,其他均呈现出根系表面】根表土壤】根内的分布趋势。大部分溶解无机磷菌株在10 d时溶磷圈直径(D)与菌落直径(d)的比值(D/d)不再增大,而溶解有机磷菌株则在14 d时不再增大。利用钼蓝比色法测定菌株溶磷能力,结果表明,109株溶解无机磷菌株培养液中有效磷含量在0.47~582.46μg·m L-1,最大为菌株PCRP5;143株溶解有机磷菌株培养液中有效磷含量在0.07~14.76μg·m L-1,最大为菌株MCMRS4;蒙金娜培养基pH与有机磷菌株有效磷含量无显著相关性(P】0.05),PKO培养基pH与无机磷菌株有效磷含量之间呈极显著负相关(P【0.01)。

Phosphate dissolving bacteria had been isolated from rhizosphere of 7 kinds of grasses based on PKO and Mehknha culture media.The results showed that there were different colony characteristics in growth rate,color,shape,edge integrity,as well as the surface condition of the ridge in different bacteria strains.The number of inorganic phosphate solubilizing strains from rhizosphere of Achnatherum inebrians showed that soil adhering to roots>rhizoplan or surface of roots>histoplan or interior of roots,strains from others grasses were rhizoplan or surface of roots>soil adhering to roots>histoplan or interior of roots distribution trend.In the first 10 days,most of the dissolved inorganic phosphorus strain's D/d stabilized,but most of the dissolved organic phosphorus strain stabilized in the first 14d.Phosphorus solubilizing capability of the strains were determined by the molybdenum blue spectrophotometry,the results indicated that there were lager differences in 109 phosphate-dissolving microorganisms capability,phosphate concentration was between 0.47 ~ 582.46 μg · m L-1,of which strain PCRP5 had the highest phosphate solubilization capacity.For the 143 strains organic phosphate dissolving bacteria,the ability to dissolve organic phosphorus was large(concentration was 0.07 ~ 14.76 μg · m L-1),the highest P concentrations was strains MCMRS4.There were no obvious relationship between the organic phosphorus strains solubilization capacity and pH(P>0.05),however pH of PKO showed significant negative relationship with the organic phosphorus strains P concentration(P<0.01).