Abstract
We grew the paddy rice from seeding time under the conditions of controlled environment in order to reveal the influence of the humidity of the atmosphere over its growth and physiology by observing how the relative humidity changed its leaf-emergence rate and leaf morphology. The obtained results were as follows: 1. The leaf-emergence rate was greater under the condition of more moist atmosphere than that of drier one. 2. The distance between the vascular bundles, the area of the mesophyll, vascular bundle and epidermis, the size of the motor cell, and the thickness of the mesophyll and epidermis were greater under the condition of dry atmosphere than that of standard atmosphere (75% of relative humidity). On the other hand, the plants grown in a relatively moist atmosphere had a larger mesophyll system and smaller epidermis system than those grown in the standard atmosphere. 3. The rice plants grown in dry atmosphere had a morphology similar to that of the plants raised under the condition of relatively low temperature and strong light, while plants cultivated in the moist atmosphere were similar to those with heavy nitrogen application.
