Morphological Studies on the Regularity of Shoots Development in Rice Plants : III. Regularity in the total number of leaves emerging on the tillers

Abstract

In order to clarify the regularity of shoot development in an individual rice plant, the relationship between the total number of leaves on each tiller and that of leaves on the main stem was investigated for four year period using 6-10 plants individually potted. The results disagreed with the generally accepted theory of "synchronous development of leaves and tillers" (Katayama, 1951). The total number of leaves on the main stem often varied by one leaf in the same plot. When compared with Katayama's theoretical total number of leaves on tiller [deduced using the smaller total number of leaves on the main stem (expressed as N-1, where N is the larger total number of leaves on the main stem], the actual total number of leaves on each tiller of different orders showed an increase with certain regularity; the number increased by 0 to 1 on the primary tillers, 1 to 2 on the secondary, 2 to 3 on the tertiary and 3 to 4 on the quaternary tillers, respectively. The present study suggests the existence of a certain regularity in the relationship between the total number of leaves on each tiller and that of leaves on the main stem. Accordingly, on each primary tiller (expressed as n₁) and on each secondary tiller (expressed as n₁ n₂), the maximum total number of leaves (referred to as L max.) -excluding prophyll-in the same plot, can be expressed as: L max. (n₁) = [(N-1) -1] -n₁ and L max. (n₁n₂) = [(N-1) -2] - (n₁+n₂). In these formulas, both n₁ and n₂ are numbered according to the nodal position counted acropetally.