Title
Immunohistology of poplar stems reveals that mannan polysaccharides are accumulated during xylem development
Authors
H.T. WANG I.H. LIU and T.F. YEH

Received November 21, 2011
Published Volume 46, Issue 3-4 March-April
Keywords carbohydrate-binding module (CBM), immunofluorescence, mannan polysaccharides, monoclonal antibody,

Abstract
Mannan polysaccharides serve as storage reserves in seeds and as structure elements in cell walls, but they may also perform other important functions during plant growth. As one of the major hemicelluloses in angiosperm wood, little is known about the presence and localization of mannan polysaccharides during xylem development in the model tree, Populus trichocarpa. In this study, we used mannan-specific recognized antibody to label mannan polysaccharides in stem tissues at different developmental stages. Immunofluorescence microscopy showed that the epitopes were localized in xylem elements, especially in thickened secondary cell walls and interfascicular fibers, while other cell types revealed a low level of mannan epitopes. The signals were possibly masked by acetylation, glucuronoxylans or pectic polymers depended on cell types, but were less affected by lignification. These results demonstrate that mannans are of particular significance in the secondary cell walls of the xylem tissue, which provides us a further opportunity to study the biosynthesis of mannans during xylem development in wood.