Studies on Translocation of Nutrients in Crop Plants : Uptake, Translocatin and Ditribution of Phosphorus, Especially Contrasted with Calcium (Part 1)

Abstract

1. To separate P^<32> from Ca^<45> we devised a method, depending upon making use their difference in β-ray energy. According to this method, P^<32> and Ca^<45>, when existed at the same time in one plant, could be traced independently, individual difference of plants being eliminated. 2. By this separation method, translocation and distribution of P^<32> and Ca^<45> in soy-bean plant were examined, and we found that the translocation rate of "Ca" was slower than that of "P", but "Ca" was translocated, as time elapsed, to the upper leaves. 3. It was concluded, therefore, that distribution and translocation of "P" would be dependent on the metabolic factors, i. e. respiration and photosynthesis. On the other hand, those of "Ca" would be dependent rather on non-metabolic factors such as exchange and diffusion. 4. In the field, the first hunger signs of "N", "P", "K" etc. usually appeared in upper leaves, while those of "Ca", "Fe", "B" etc., in lower leaves. This phenomena was possibly due to the difference of translocation rate in the plant of each nutrient.