Variation in morphology, anatomy and chemistry of stems of Miscanthus genotypes differing in mechanical properties

Abstract

The aim of this experiment was to measure the chemical composition and morphological and mechanical properties, and to determine the contribution of different tissue components and chemical constituents to the modulus of elasticity of Miscanthus. Randomly selected stems of Miscanthus ‘Giganteus’, 10 numbered clones and 6 named cultivars of M. sinensis were harvested in February 1999. Determination of morphological characteristics included counting the number of internodes, measurement of the length of stems and internodes, and size of outer and inner diameter. Culm wall thickness, cross sectional stem area and moment of inertia were calculated, and modulus of elasticity was measured using a three point method. Chemical analysis included determination of the concentration of dry matter, cellulose, lignin, and ashes. Studies of anatomy encompassed determination of number of vascular bundles, area of parenchyma vascular bundles, and outer heavily lignified ring (outer ring). Substantial variations and significant differences between genotypes were found for all morphological and anatomical characteristics and for concentrations of chemical constituents except dry matter. A stepwise regression analysis was carried out on the relationship between modulus of elasticity as the dependent variable, and the morphological characteristics, anatomical characteristics, and the concentration of chemical constituents as independent variables. Modulus of elasticity depended significantly of the area parenchyma vascular bundles and outer heavily lignified tissue (outer ring) and of the concentration of lignin and cellulose. Based on the measured characteristics it was hypothesized that the cultivar ‘Purpurescens’ may have the highest lodging resistance followed by ‘Braunschweigh’ and ‘Giganteus’.