Cell-wall hemicelluloses as mobile carbon stores in plants.
PhD Thesis, University of Basel,
Faculty of Science.
Official URL: http://edoc.unibas.ch/diss/DissB_8909
Hemicelluloses are the second most abundant polysaccharide in nature after cellulose. So far, the chemical heterogeneity of cell-wall hemicelluloses and the relatively large sample-volume required in existing methods represent major obstacles for large-scale, cross-species analyses of this important plant compounds. Here, we apply a new micro-extraction method to analyse hemicelluloses and the ratio of ‘cellulose and lignin’ to hemicelluloses in different tissues of 28 plant species comprising four plant functional types (broad-leaved trees, conifers, grasses and herbs). For this study, the fibre analysis after Van Soest was modified to enable the simultaneous quantitative and qualitative measurements of hemicelluloses in small sample volumes. Total hemicellulose concentrations differed markedly among functional types and tissues with highest concentration in sapwood of broad-leaved trees (31% d.m. in Fraxinus excelsior) and lowest concentration between 10-15% d.m. in leaves and bark of woody species as well as in roots of herbs. As for total hemicellulose concentrations, plant functional types and tissues exhibited characteristic ratios between the sum of cellulose plus lignin and hemicelluloses, with very high ratios (> 4) in bark of trees and low ratios (< 2) in all investigated leaves. Additional HPLC analyses of hydrolysed hemicelluloses showed xylose to be the dominant hemicellulose monosaccharide in tissues of broad-leaved trees, grasses and herbs while coniferous species showed higher amounts of arabinose, galactose and mannose. Overall, the microextraction method permitted for the simultaneous determination of hemicelluloses of various tissues and plant functional types which exhibited characteristic hemicellulose concentrations and monosaccharide patterns. © 2009 Elsevier Masson SAS. All rights reserved
|Committee Members:||Richter, Andreas|
|Faculties and Departments:||05 Faculty of Science > Departement Umweltwissenschaften > Botanisches Institut > Pflanzenökologie (Körner)|
|Bibsysno:||Link to catalogue|
|Number of Pages:||0|
|Last Modified:||30 Jun 2016 10:41|
|Deposited On:||18 Feb 2010 07:08|
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