Scaphium macropodum
(Miq.) Beumee ex Heyne (Sterculiaceae) in a tropical rain forest in West Kalimantan (Indonesia) was analyzed from the viewpoint of statics. The petiole diameter must increase with increasing leaf size to retain enough mechanical stability and a sufficient amount of conductive vessels. The petiole's cross-sectional area at its base was found to be proportional to the leaf blade's dry mass, which indicates that Shinozaki's pipe model is applicable to leaves with different sizes. Although larger leaves produce greater bending moments on the petiole's cross-section as a result of their greater weights, the bending stresses at the petiole's base caused by the leaf's weight were constant at ca. 76,900 g cm−2 regardless of leaf size. Thicker petioles increase the leaf's mechanical stability, but require sizable energy investments for their construction. It is hypothesized that the constant value for petiolar stress indicates an optimal balance between energy economy and the mechanical stability of S. macropodum leaves. To keep bending stress constant, the leaf blade's center of gravity shifts to a more proximal position and the cross-sectional area of the petiole increases.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received 8 December 1997/ Accepted in revised form 1 December 1998
Rights and permissions
About this article
Cite this article
Yamada, T., Suzuki, E. & Yamakura, T. Scaling of Petiole Dimensions with Respect to Leaf Size for a Tropical Tree, Scaphium macropodum (Sterculiaceae), in Borneo. J Plant Res 112, 61–66 (1999). https://doi.org/10.1007/PL00013859
Issue Date:
DOI: https://doi.org/10.1007/PL00013859