Accessibility and Lateral Order Distribution of the Cellulose in the Developing Cotton Fiber1

Abstract

Cotton fibers from bolls harvested at 5-day intervals beginning at 20 days after flowering and ending at 50 days ( when the bolls had opened on the plant) 'were preserved in three ways for study in the never-dned state. Preservation was accom plished in 70% aqueous ethanol, 50% aqueous dioxane, and by freezing. Measurements of iodine sorption, red-green ("differential") dye uptake, and liquid-phase deuteration rehydrogenation gave different kinds of estimates of accessibility. These data were interpreted as indicating a relatively open structure during the 20- to 30-day period of growth, and a consolidation of the cellulosic component of the cell wall during the subsequent period of wall-thickening (35 to 45 days after flowering). There was only a small change in magnitude of these data upon boll opening. The leveling-off D.P. was nearly constant from the 30th to the 45th day, but showed a slight decrease after boll opening.