20 research outputs found
PCR-Amplification and Cloning of the Coding Region of a cDNA for a Reversibly Glycosylated Polypeptide from Rice with Possible Involvement in the Biosynthesis of Glucans
β-D-Glycan synthases and the CesA gene family: lessons to be learned from the mixed-linkage (1→3),(1→4)β-D-glucan synthase
Cloning and characterization of a putative UDP-rhamnose synthase 1 from Populus euramericana Guinier
Cell wall hemicelluloses as mobile carbon stores in non-reproductive plant tissues
As essential compounds of plant cell walls, hemicelluloses account for about a quarter of all plant biomass worldwide. In seed cotyledons and endosperm of species from several plant families, hemicelluloses are used as mobile carbon reserves. Whether cell wall hemicelluloses of non-reproductive plant tissue are multifunctional molecules, which can also serve as carbon sources during periods of enhanced carbon demand, is still equivocal. This review summarizes the current understanding of a possible reserve function of hemicelluloses. Although several descriptive and experimental studies suggested at least partial mobility of cell wall polysaccharides in mature, non-reproductive plant tissues, there is still a need for a broad-scale, ecophysiological exploration of the actual nature of hemicelluloses beyond their structural function. The chemical heterogeneity of hemicelluloses may be the major problem for precise quantitative analyses on a large, comparative scale. Because of the abundant distribution of hemicelluloses in plants, the existence of a significant mobile carbohydrate pool in cell walls of non-reproductive organs would shed rather new light on plant carbon relations in a source-sink context. Consequently, a reserve function of hemicelluloses questions the conventional division of cell compounds into structural (i.e. immobile) and non-structural (i.e. mobile) compounds