IMMUNOHISTOLOGY OF POPLAR STEM REVEALS THAT MANNAN POLYSACCHARIDES ARE ACCUMULATED DURING XYLEM DEVELOPMENT

摘要

Mannan polysaccharides serve as storage reserves in seeds and as structure elements in cell walls, and they may also perform other important functions during plant growth. As one of the major hemicelluloses in wood of angiosperm, little is known about the presence and localization of mannan polysaccharides during xylem development in the model tree, Populus trichocarpa. In this study, we use mannan-specific recognized antibody to label mannan polysaccharides in stem tissues of different developmental stage. Immunofluorescence microscopy showed that the epitopes were localized in xylem elements, especially in thickened secondary cell walls and interfascicular fibers, and the signals are consistent with lignification. Other cell types reveal low level of mannan epitopes. These results demonstrate that mannans are particular significance in lignified cell walls in xylem tissue, which provide us a further opportunity to study biosynthesis of mannans during xylem development in wood.