玉米根际溶磷细菌的分离、筛选及溶磷能力研究

采用传统的微生物分离培养法,对玉米根际溶磷细菌进行分离,筛选出38株解无机磷菌株和35株解有机磷菌株,并发现无论是细菌总数,还是溶磷细菌总数,根际土壤都比非根际土壤要多.对筛选获得的73株菌株进行菌落形态观察发现,大多数菌落呈乳白色或黄色、形状不规则或近圆形、光滑黏稠、扁平、不透明、边缘不整齐.进一步利用钼锑抗比色法测定其溶磷能力,发现无机磷菌株溶解的有效磷含量与培养液pH之间存在显著的相关性,有机磷菌株则无明显相关.各菌株溶解磷酸钙和卵磷脂的能力差异较大.无机磷菌株和有机磷菌株对无机磷(磷酸钙)和有机磷(卵磷脂)的溶磷量分别为8.88～108.31和0.51～3.53 mg/L.菌株中SWJ1-4和SWJ3-1溶解无机磷能力较强,RYJ1-6溶解有机磷能力较强,且这3株菌株生长快、生长状况良好,在后续微生物菌肥研制中具有较大潜力.

A Study on the Isolation, Screening and Phosphate Solubilizing Capacity of Phosphate Solubilizing Bacteria in the Rhizosphere of Corn

Phosphate-solubilizing bacteria were isolated from the rhizosphere of corn, and 38 strains of inorganic phosphate-solubilizing bacteria and 35 strains of organic phosphate-solubilizing bacteria were screened by using traditional method of isolation and culture of microorganisms. The number of both total bacteria and phosphate-solubilizing bacteria in the rhizosphere soil was higher than that in the bulk soil. Major bacterial colony was milky or yellow, irregular or roughly round, smooth, thick, flat, non-transparent with ragged edge. Furhter study on phosphorus solubilizing capacity of the strains by Mo-Sb colorimetry method indicated that pH was significantly correlated with the content of available P of inorganic phosphate-solubilizing bacteria strains, but not correlated with that of organic phosphate-solubilizing bacteria strains. There were great differences between solubilizing calcium phosphate by inorganic phosphate-solubilizing bacteria and solubilizing lecithin by organic phosphate-solubilizing bacteria. Their phosphate-solubilizing capacity ranged from 8.88 to 108.31 and 0.51 to 3.53 mg/L, respectively. The strain SWJ1-4 and SWJ3-1 had a higher ability in solubilizing inorganic phosphate than other strains and strain RYJ1-6 had a higher capacity in solubilizing organic phosphate. The three strains had great potential in further development of microbiological fertilizer because of their stronger phosphate-solubilizing ability, faster growth rate and better growing state.