抄録
We measured the amount of co2 exhaled by the rice plants which were cultivated changing the opening time of flood irrigation and obtained the following results. 1) During the experimental term from 10th of July to 26 th of Sept., we found twice the increasing tendency of the amount of co2 exhaled in every plot, the first it was found at the time of tillering and secondly just before heading. 2) The first max. exhalation of the transplanting plot was delayed more than ten days to that of the direct planting. This may be attributable to the physiological hindrance caused from transplanting and is correspond to the fact that the max. tillering of the former was more than ten days later than that of the latter. 3) The amount of co2 exhaled showed some tendency to increase at fifth day after starting flood irrigation, this may come from the sudden change of cultivating condition. 4) The amount of co2 exhaled by the rice plants which were cultivated in the pots of field state throughout the experiment showed various results according to the amount of water in the soil. This may be counted to the affinity of rice plant to water. 5) The amount of co2 exhaled seemed to concider rather with the cultivating method than the growing condition of rice plant.
