OPTICAL EMISSION SPECTROGRAPHIC STUDIES ON DISTRIBUTION AND ACCUMULATION OF NANOGRAM AMOUNTS OF N-15 IN RICE SEEDLINGS

An optical emission spectrographic method was used to study the distribution and accumulation of nanogram quantities of 15N in leaves and roots of individual rice plants. Gaseous nitrogen that was prepared from plant samples, not weighing more than 100 μg, was trapped in an electrodeless tube. The excess 15N was determined by exciting the gas with a high frequency generator, then measuring the light intensities of the molecular bandheads at 2977, 2983 and 2989 Å. For leaves that contained 4 atom % 15N the precision obtained was ±1.33%. A comparison of emission and mass spectrographic 15N values were obtained with a number of second leaves of rice plants that were grown under similar environmental conditions. The 15N contents obtained at a 2 atom % level by the 2 methods were in reasonable agreement. © 1969 Oxford University Press.