作物の養分吸収に関する動的研究(第6報) : 作物根中の Ca^<45> の置換浸出に就て

抄録

The depletion of Ca from metabolising barley and wheat roots was studied by employing tracer technique of Ca^<45>. The basic technique with special regard to the self-absorption of Ca^<45> was preliminary established as shown in Table 1 and Fig. 1. The outward movement of Ca^<45> was remarkable in the chloride of K, NH_4,Rb, Mg, Ca, Sr and Ba except for Li and Na in contrast to H_2O (Table 2,4). The highly hydrated ions as Li and Na might have failed to deplete Ca. Unexpectedly, however, no significant differences were observed among other ions. This is the marked contrast to K^<42>, which has been reported to be depleted exclusively by K. A series of enzymic inhibitors as shown in Table 5 did not affect the depletion except for dinitrophenol. The elevation of temperature from 6°-20℃, however, more or less promoted its outward movement (Table 4). This apparent discrepancy was discussed on the basis of metabolic activity. Further, different anions showed no remarkable difference (Table 7). The alternate treatmeut with H_2O and salt solutions for the same plant root gave definite proof that the depletion, so far as this study was concerned, was a normal process of healthy metabolising roots and no sign of injury, as might be expected on the use of single salt solution, could be observed (Table 6,Fig. 2). In conclusion, the status of Ca held in metabolising plant roots would be a more or less loose bonding as compared to K and yet a little stronger than Na, its linkage being almost, if not entirely, independent of the normal metabolism.