Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 1, 2003
Publication Date: August 1, 2003
Citation: Inglesby, M.K., Wood, D.F., Gray, G.M. 2003. The cell wall components of oryza sativa. Society of Wood Science and Technology, Alexandra, Louisiana, August 2003, Abstract. Technical Abstract: It has long been established that the gramineous rice plant Oryza sativa is silicon-accumulating plant that actively absorbs monosilicic acid through the roots and stores the element as silicon dioxide (SiO2) in a hydrated, polymerized form in the stem, leaves, and husk. Though its high SiO2 content has been claimed to be the culprit that prevents rice straw use in many processes, such as pulping / fractionation, little characterization of treated samples with respect to silicon content and distribution appears to exist. In this study, the localization of SiO2 was determined in untreated rice stem tissue as well as in pulped stems by energy dispersive X-ray (EDX). 2-D elemental spatial distribution maps clearly showed the distinct localization of SiO2 in stem control samples. Pulping treatments, to include soda (NaOH) pulping, EtOH, and formic acid organosolv pulping differed in their effects on the stems. Acid-insoluble ash contents were determined, by adapted TAPPI methods, of these stems and of rice straw samples subjected a) to the above mentioned pulping treatments, and b) to clean-fractionation performed at the DOE, NREL in Golden, CO. The final acid-insoluble ash fractions were submitted for elemental analysis to establish the amounts present of silicon and of other inorganic constituents. The sample surfaces and cross-sections were characterized by scanning electron microscopy. The use of FTIR as a rapid qualitative tool for the detection of SiO2 was explored.