Morphological Analysis on Mechanical Strength of Leaf Blades in Erianthus

Abstract

Erianthus, a perennial C₄ grass, is a raw material for cellulosic bioethanol, mainly because it has high potential for biomass production based on its large canopy. In this study, the mechanical strength of the leaf blade was examined with reference to its morphology. The results showed that the weight and mechanical strength of leaf blade increased basipetally along the leaf axis. The potential weight of the blade to support itself, estimated from the mechanical strength measured with a force-gauge, was not less than the actual leaf weight. These results are in agreement with the actual conditions of the canopy, and suggest the validity of our methodology. Measurement of the mechanical strength of only the midrib itself indicated that the mechanical strength of the whole leaf blade was mainly based on the development of the midrib which was larger and had changed from circular to U-shaped basipetally along the leaf axis excluding the leaf tip with undeveloped midrib. These results suggested that the size and shape of the midrib contribute to the mechanical strength to support the leaf blade.