A quantitative analysis of plant form;the pipe model theory,1.

Abstract

SHINOZAKI, K., K. YODA, K. HOZUMI ard T. KIRA (Osaka City Univ., Osaka) A quantitative analysis of plant form-the pipe model theory. I. Basic analyses. Jap. J. Ecol. 14,97-105 (1964). Examining the profile diagrams of various plant communities showing the vertical distribution of the amounts of leaves and other non-photosynthetic organs at respective horizons above the ground, a close correlation was found between the distributions of the two amounts. The amount of leaves existing above a certain horizontal level in a plant community was always-proportiona1 to the sum of the cross-sectional area of the stems and branches found at that level. This led to a new interpretation of plant form, in which the stem and branches were considered as the assemblage of unit pipes each supporting a unit amount of photosynthetic organs. In trees, the disused pipes, which had once supported the leaves on the already shed-off branches, remain in the trunk and boughs together with the working pipes connected with the living leaves. A specific shape of tree Shoot is thus formed. This pipe model theory on tree form proved to be applicable to various conifers and hardwoods.