THE P32 INJECTION METHOD FOR STUDYING THE ROOT SYSTEM OF WHEAT

Abstract

A new technique involving the use of P32 for the study of plant root development is described. Carrier-free P32 was injected into the stem of wheat plants using a microliter syringe. After allowing 5 days for the P32 to distribute throughout the total plant system, soil–root cores were taken, ashed at 500 °C, and the activity of a pressed soil briquet was determined.The amount of roots measured by the injection method was compared to the more laborious root-washing procedure. Very close agreement between the two methods was realized when the activity of the soil–root cores was recalculated to measure the per cent distribution of the roots within a particular core as compared to the total depth sampled. Preliminary data are reported on experiments designed to estimate the influence of various factors such as phosphate fertilization, soil types, and moisture stress on root development.