Abstract
Photosynthetic activities of wheat and barley, grown on a field, were measured using a plant chamber, shown in Fig. 1 which had been modified and improved from that of the previous paper. The results obtained were as follows. 1) Light intensity was the most important factor in determining the photosynthetic activities of wheat and naked barley grown on a field as already reported in the previous paper with rice plants. However, the requirement of light intensity for saturation in wheat and barley communities was considered to be comparatively lower than in rice plants. 2) Seasonal changes of photosynthetic rate of wheat and barley are shown in Fig. 5. In wheat the photosynthetic rate gradually increased with the growth, attaining maximum at the internode-elongation-stage, and remaining approximately at the same level until the milk-stage. Subsequently the rate declined with the process of ripening of the grain. In barley, the rate increased considerably during the period from the stage of internode-elongating to that of early milk-ripening, although fluctuations in the rate were observed after heading period. In the subsequent ripening stage, the rate declined rapidly.
