Abstract
Potted plants of the lowland rice variety, Norin 37, were used for the measurement of the ventilating pressure at intervals of bout 2 weeks after transplanting. The results obtained are as follows: 1. The ventilating pressure varied with the degree of expansion of stomatal openings and with the number of green leaves. Particularly important was the position on the stem where the lowest green leaf was attached. 2. Specific differences between the main culm and tillers in the ventilating pressure were discernible at the growth stages prior to heading, but they diminished towards maturity. 3. Seasonal changes in the ventilating pressure was recognized decidedly, the pressure being lowest at the stage of differentiation of ear-primordia. 4. Oxygen transference from the top to the roots might reasonably be affirmed.
