4种优良牧草根际PGPR分布特征研究

Study on the distribution characteristics of plant growth promoting rhizobacteria(PGPR) from the rhizosphere of four high-quality herbages

为了筛选高寒草原牧草植物根际促生菌(PGPR)菌株资源,探究其分布规律,试验利用无氮(NFM)培养基、PKO无机磷、蒙金娜有机磷培养基对高寒草原优良牧草披碱草(Elymus dahuricus)、燕麦(Avena sterilis Linn)、紫花苜蓿(Medicago sativa)和草地早熟禾(Poa pretensis)根际的固氮菌、溶磷菌按根系较远的土壤(NRS)、根表土壤(RS)、根系表面(RP)和根内(HP)4个区域的PGPR菌株进行分离、分析。结果表明:从4种供试植物根际共分离到PGPR菌株222株,其中固氮菌71株、溶解无机磷菌株73株、溶解有机磷菌株78株;PGPR菌株数量在植物根际的分布均表现出根表>根表土>远根土>根内的分布趋势。说明PGPR的分布表现出强烈的根际效应。

To screen the plant growth promoting rhizobacteria （PGPR） strain resources of herbages in alpine grassland, and investigate their dis- tribution law, the nitrogen - free medium （ NFM ）, PKO medium with inorganic phosphorus and Menjinna organic phosphorus medium were used in the test. And then PGPR strains in nitrogen fixing bacteria and phosphate solubilizing bacteria from the rhizosphere of four high - quality herbages, including Elymus dahuricus, Avena sterilis Linn, Medicago sativa, and Poa pretensis, were isolated and analyzed according to four different regions of the rhizosphere, including soil away from roots （ NRS）, rhizosphere soil （ RS）, surface of roots （ RP）, and interior of roots （HP）. The result showed that 222 PGPR strains were isolated from the rhizosphere of the four plants, including 71 strains of nitrogen fixing bacteria, 73 strains of solubilizing inorganic - phosphorus bacteria, and 78 strains of solubilizing organic - phosphorus bacteria. The distribution of the number of PGPR strains showed a descending order as follows： RS, RP, NRS, and HP. The result indicates that the distribution of PG- PR presents a strong rhizosphere effect.