Morphological Studies on the Regularity of Shoot Development in Rice Plant. V. The regular modification in changes of organ length on main shoot with the same total leaf number.

Abstract

In a field plot where rice seedlings were planted as a single per hill, a difference of one leaf appeared in the total leaf number of the main shoot. Therefore, the main shoot with 'n' leaves and those with '(n-1)' leaves were designated 'N type' and 'N-1 type', respectively. Both types have different patterns of changes in the length of elongated internodes and laminae succesively developed on the main shoot. In addition, the above 'laminae pattern' makes a reversed V shape on a line graph; however, the peak of reversed V shape, namely the longest lamina appeared in node order of '(n-2)' or '(n-3)', which are counted basipetally from the top node of the main stem with 'n' leaves. The comparison of the group having the peak on '(n-2)' node to the other one having the peak on '(n-3)' node are made in N or N-1 types. The result was that the main shoots of N type and those of N-1 type are separated into two subtypes by the positions of the above peaks, respectively. That is, the subtype with '(n-2)' peak differs from the other subtype with '(n-3)' peak in the following aspects: (1) upper internodes are longer but lower ones are shorter, and (2) upper laminae are longer but lower ones are shorter. At the same time, the result by the test of normality defined quantitatively the above subtypes.