Cell walls of leaves from native woody bamboo Guadua chacoensis (Poaceae, Bambusoideae, Bambuseae)

PAULA VIRGINIA FERNÁNDEZ; ANDREA SUSANA VEGA; MARINA CIANCIA

Buenos Aires

Simposio; First Argentinean Symposium of Glycobiology; 2014

Cell walls of leaves from native woody bamboo Guadua chacoensis (Poaceae, Bambusoideae). Fernández P.V.1,2, Vega A.S.3, Ciancia M.1,2 1Cátedra de Química de Biomoléculas, FAUBA; 2CIHIDECAR-CONICET-FCEN-UBA; 3 Cátedra de Botánica Agrícola, FAUBA. Guadua chacoensis (Rojas) Londoño & P. M. Peterson is a native woody bamboo that grows in Northeast Argentina. It represents a renewable resource that can provide polysaccharides and oligosaccharides with different potential applications, and it can also be used as forage. A detailed knowledge of cell wall polysaccharides is required to develop those applications. To reach this goal, the alcohol insoluble residue from leaves of G. chacoensis was subjected to a sequential extraction comprising hot water, 0.05M CDTA, 0.05M Na2CO3, 1M and 4M KOH. As expected, yields and composition of the extracts showed that pectins are minor components of these cell walls, meanwhile hemicelluloses and cellulose are their major carbohydrate constituents. Accordingly, the major extract, which was obtained with KOH 1M (11% of the cell wall mass), consists of xylose, arabinose, glucose and galactose (56%, 26%, 10% and 8%, respectively). Methylation analysis and NMR spectra show the typical structure of an arabinoxylan, with a main chain composed of β-(1→4)-Xylp units, with a complex pattern of substitution that includes arabinofuranosyl, galactosyl glucuronosyl residues combined in different arrays. Small amounts of mixed linkage glucans, an hemicellulosic polymer characteristic of gramineous plants, were detected in various cell wall extracts.