Abstract
Changes in oxygent content of the solution surrounding the root were measured with eirher the intact or excised root separately by means of polarography using microplatinum electrode. Rice plants (var. Aichi asahi) were grown by solution culture up to its ten-leaf stage and they were used as material. When an excised root was immersed in the solution was shut off from the open air, oxygen content of the solution rapidly decreased at the rate of 0.101 ml/l/min/gm. In case of intact plants, however, the oxygen content rapidly increased after a slight decrease and reached its maximum after about 4 hours. On the other hand, when the plant from which the upper part (leaves and culm) was cut away at the base was set up to the apparatus in such a position so that the cut surface might be exposed to open air, increase of oxygen content in the solution was considerably slight and oxygen concentration did not reached its maximum at all. From these results, it was concluded that oxygen can also be send into the root from leaves through the plant body in intact rice plant and its supply excesses the amount of oxygen consumption at the root. Accordingly it is assumed that there exists some physiological mechanism for the active transportation (pumping up) of oxygen in rice plant body.
