抄録
(1) Rice plants, the variety Shin No. 2, were cultured in a glass house being kept from cold weathers in the fall; and, during the period from heading to 20 days after heading, some of the plants were put in a dark room for 3 days, and on the other hand some were placed in the open air for 7 days, both to check temporarily the nutrient translocation to the kernels; and then were examined the occurence of notched-belly in them. (2) The notched-belly kernels occured numerously when the nutrient translocation to the kernel was seriously checked for a few days during a period of 5-20 days after flowering. (Fig. 4.) When the nutririent translocation was checked, in certain varieties of rice plants, starch cells of the middle portion of the kernel nearly stopped their growth in dorso-ventral direction, but those of the other portion continued their growth after the recovering of nutrient translocation. In such a case, the dorsoventral diameter at that portion remained as it was at the stage of that time, and consequently kernel was formed into a notched-belly shape. (3) When the nutrient translocation was checked and the growth in dorso-ventral diameter at a limited portion of the kernel ceased at 5-7 days after flowering, the kernel became acutely notched. Usually, such a kernel was shorter in length and rather longer in dorso-ventral diameter than the normal kernel. (Fig. 5.) (Table. 1) When the restriction of nutrient translocation occured at about 15 days after flowering, the kernel was obtusely notched, and the length of the kernel was similar to that of the normal one while its dordo-ventral diameter was shorter.
