Nonstructural and Structural Carbohydrates

Effects of increased [CO2] and temperature on the concentrations of nonstructural carbohydrates (glucose, fructose, sucrose, and starch), hemicelluloses (rhamnose, o-methyl-glucuronic-acid, mannose, arabinose, galactose, and xylose), and lignin and cellulose are quantified for different tree organs. A deciduous, broad-leaved and a coniferous, evergreen needle-bearing species are presented as examples. Starch increased in sun and shade leaves. Daily courses show the great enhancement of starch but not sucrose production under elevated [CO2]. Higher temperature leads to lower starch concentrations. In contrast to starch, glucose, fructose, and sucrose are accumulated in the stem basis (Pinus sylvestris). More mannose and less arabinose are found in the stem of Pinus sylvestris at elevated [CO2]. Only galactose concentration increases after warming. All other hemicelluloses show no clear changes. Antagonism of cellulose and lignin concentration is shown in response to increased [CO2] and temperature. For instance, lignin increases with higher temperature and cellulose concentration decreases.