Abstract
Six wheat young plants were cultivated in each Wagner pot. On March 20th 1952,when wheat plant is in very-young-head forming period, one pot was manured with nitrogen and phoshate containing radioactive phosphorus and the other control pot was manured with only phosphate as is shown in Table 1. After 63 hours of top-dressing, 3 plants were sampled from each pot, dried in a steam oven, weighed, and then burnt in an electric furnace ; the ashes were disolved with HCl in stainless-steel counting cup, then dried under infrared lamp. Each cup was measured its radioactivity by Geiger-Muller counter. Datas shown in Table 2 suggest that nitrogen dressing followeb intense increase of the phosphate intake by wheat almost 5 times as that of control. After 80 hours of top-dressing, one plant from each pot was sampled, analyzed into each part carefully, and then dried by electric iron to pressed leaves. These pressed leaves were radioautographed as shown in Fig. 1 and 2. These radioautographs show that fertilized plant accumulated more radiophosphorus, and that. P^<32> was condensed especially in the very-young-head Two plants remained in each pot were grown to their ripening. On July 5th 1952,almost matured plants were sampled, devided into several organs, then dealt with the same method as above, mentioned to determine their radioactivities. From Table 3 and 4,we can estimate that paleass rachis, bootleaf, and nodes in fertilized plants have accumulat-ed two times or more of radiophorus as that of control at their matured stage.
