Quantitative analysis for the cellulose I α crystalline phase in developing wood cell walls

Abstract

FT-IR and X-ray analyses were employed to determine the relative ratio of cellulose I α and I β crystalline phases present in each developmental stage of coniferous tracheid cell wall formation. The IR spectra showed that initially the I α phase occupies 50% of the crystalline regions in the primary cell wall cellulose and this value drops to 20% after ceasing of the cell enlarging growth for the formation of the secondary wall cellulose (the remaining regions are composed of the I β phase). Although it is reasonable that the content for I β , which is stress-reduced crystalline form, was higher in the secondary wall formation (Kataoka Y, and Kondo T. Macromolecules 1996;29:6356–6358) it is more interesting that during the crystallization of stress-induced I α cellulose for the primary wall the stress-reduced I β is also possible to be crystallized in an alternative way. This means that throughout the period the I α -causing stress may not be necessarily kept loaded. In light of our previously reported hypothesis (Kataoka Y. and Kondo T. Macromolecules 1998;31:760–764) for the formation of I α phase due to cellular growing stresses in the primary wall cellulose, such an alternating on–off stress effect to account for the occurrence of both I α and I β phases might be related to a biological growth system in coniferous wood cells.