| Abstract: | The utilization of 18O labelled potassium phosphate KH2P18O4, instead of radiophosphorus, 32P, labelled phosphate in biochemical and ecological studies concerning fertilizer phosphorus assimilation by plants is presented. The 30–60 mg dry plant samples were heated under 10?2 mm Hg vacuum in Pyrex ampoules to form carbon dioxide (C16O18O) for 18O mass spectromietric analyses. Potassium phosphate labelled with 1.36 18O atom per cent is sufficient to obtain a significant increase of the 18O plant content, the added 18O quantity in 0.5 kg soil being 1.4 × 10?2 g 18O in this case. |
