The incidence of apatite-solubilizing organisms in the rhizosphere and soil

Abstract

A number of microorganisms capable of solubilizing apatite mere isolated from soil and from the rhizosphere of plants. Many genera of common soil fungi and bacteria were represented. The organis~ns solubilizing apatite were consistently present in higher proportions in rhizosphere isolates than in those from nearby soil. The zone of solution of apatite surrounding colonies on agar plates was usually characteristic of organisms producing acid in liquid culture; however, the degree of solubilization was not proportional to the fall in pH. On subculturing, many isolates rapidly and irreversibly lost their ability to dissolve apatite. Soil isolates lost their ability to solubilize apatite more readily than isolates from the rhizosphere.