The Sterile Culture of Plants in Soil

Abstract

In his paper (1) Gerretsen described a method developed by him for the prolonged cultivation of plants in quartz sand under sterile conditions. By growing plants in this fashion, he was able to demonstrate that microorganisms had the power of rendering soluble (if only in part) such unavailable forms of phosphate as tri-calcium phosphate, bone meal, Morocco and Algerian phosphates, and that this action made more phosphate available for uptake by plants. He also definitely proved that in the absence of microorganisms the roots possessed some method of solubilizing difficultly-soluble phosphates. This was shown by the fact that sterile plants supplied with an insoluble phosphate took up quite an amount of phosphate when there were no microorganisms present; the amount, however, was less than that absorbed in the presence of microorganisms.