Abstract
Rice plants, Variety Norin 37, were grown on the paddy field according to the usual culture plactices. They were covered by shading frames which have several light transmission factors at the various growing stages. Increasing of dry matter weight during the treated period and photosythetic ability was measured, and also the other physiological factors. The results obtained were as follows: 1) The increasing of dry matter weight had an intimate correlation with the light intensity in case of comparatively high light intensity throughout each stage. 2) In case of slightly shading, the photosythetic ability of a rice community developed more than normal ones at the end of 1 week after the initial shading treatments. It is due mainly to the increasing of unit photosynthetic ability, on fresh leaf weight basis. 3) The relation between the photosynthetic ability of fresh leaf weight basis and the water content in a leaf are shown at figure 9, which brings out of the fact that they have an optimum point, but this is changeable in accordance with the growing stages.
