抄録
Along the successive "shoot units" (abbreviated as SUs) on main stems of rice plants, the number and diameters of primary roots were compared with several morphological characters of the shoots. Each shoot was composed of 16 SUs, and acropetally towards the 11th SU, many characters examined tended to increase almost linearly. The characters involved here were the lengths of leaf blades, leaf sheaths and internodes, the diameters of the stem, as well as the diameters of vascular cylinder of the stem, and further the number and the diameters of primary roots, respectively. From the 12th SU upwards, on the contrary, almost all characters mentioned above, except the internode lengths, tended to decrease. These higher SUs were characterized by the remarkable elongation of their internodes. The primary roots appeared near the 12th SU showed peculiar phenomena, i.e. the abundant occurrence of dormant root primordia and the considerable decrease in their diameters. The results obtained suggest that a close growth correlation may exist among various organs of each SU, and the internodal elongation or related internal factors may change the correlation to a great extent.
