抄録
Histological comparison between the injured grains obtained naturally or artificially and the normal grains at the various developmental stages was performed. The results of observations were as follows. 1. The immature grains were classiable into three types, death type, near death type and gradual death type. These types differed in the process to interruption of development, but the inferior development of pericarp, embryo and especially endosperm was common to the types. The immature grains tended to occur, when the ovaries or grains met with a low temperature at few days before or after the flowering. 2. The shrivelled or concaved grains were characterized by the loss of endosperm in a middle part of the grains, although the development of pericarp and embryo were complete. These grains were generally originated from the normal grains which were attacked by a low temperature at over a week after the flowering. 3. The chilling injury at the flowering stage will be interpreted as the results of entire or partial interruption of the endosperm development by a low temperature.
