A Study of the Breakdown of Organic Phosphates by Micro‐organisms from the Root Region of Certain Pasture Grasses

Abstract

A survey of micro‐organisms isolated from the root surface, rhizosphere soil and nonrhizosphere soil of pasture grasses (Ryegrass, S23; Timothy, S50; Cocksfoot, S143) was made to determine their ability to attack phenolphthalein diphosphate, sodium glycerophosphate, sodium phytate, lecithin, ribonucleic and deoxyribonucleic acids. The total numbers of organisms capable of decomposing these compounds were higher on the root surface and in the rhizosphere soil of the grasses when compared with the numbers in nonrhizosphere soil. Occasionally, preferential stimulation of organisms hydrolysing some of the compounds was observed in the root regions. The addition of deoxyribonucleic acid to medium inhibited the numbers of colonies developing in dilution plate counts. This inhibition was generally more pronounced on root surface organisms than on those from nonrhizosphere soil.