hemicelluose to cellulose of structural polysaccharides in plant materials including
wood of angiosperms and conifers, straw, leaves (grasses, herbs, and trees) ranges
between 0.5 and 1 (Hoch 2007; Shädel et al. 2010).
6.3.1.2 Monosaccharide Composition of Soil Polysaccharides
Few studies have reported monoaccharide composition of soil analyzed by two-step
acid hydrolysis procedure of Oades et al. (1970). Some studies cited here determined
sugar monomers released by the primary hydrolysis only of the two steps (Folsom
et al. 1974; Whitehead et al. 1975), and did not give both NEH-glucose content and
the total neutral saccharide content, but enabled calculation of the molar ratio of
GM/AX. Another study determined sugars by a high performance liquid chromatography on the combined hydrolysates obtained by two-step hydrolysis, thus the
ratio of EH-glucose/NEH-glucose was unknown (Murayama 1977a, b). Therefore,
the quantity of available data differs among Figs. 6.1, 6.3, 6.4 and 6.5. Except in
Sect. 6.5, the present article used only data for soil from the A horizon of non-arable
land, and the Ap horizon of arable land.
EH-glucose was the most abundant sugar across all soil groups (Fig. 6.3). But, the
monosaccharide composition of forest soil and forest-derived arable soil is quite
different from that of non-forest soil. The former soil is characterized by significantly
much larger proportions of EH-glucose, mannose, and by significantly much smaller
proportions of NEH-glucose, arabinose and smaller proportion of xylose. The proportions of galactose, rhamnose, fucose, and ribose are statistically not different.
6.3.1.3 Comparison of Composition Between Plant and Soil
Incorporation of woody plant materials into non-forest soil is unusual. Non-forest
soil (Fig. 6.3) is constituted of significantly larger proportion of galactose, mannose,
fucose, and rhamnose than herbaceous plants material (Fig. 6.2). Proportion of
EH-glucose is also greater in soil than plant materials at p ¼ 0.065. Some portion
of these sugars might be synthesized by microorganism in the soil as components of
polysaccharides.
It is notable that the proportion of arabinose of non-forest soil (average (av);
14.8%) is significantly much greater than that of herbaceous plant materials (av;
4.74%), though the proportion of another pentose xylose in soil (av; 15.2%) is
significantly much smaller than herbaceous plant materials (av; 31.8%)
(Fig. 6.3 vs. Fig. 6.2).
Tracer studies on microbial synthesis from
14 C or
13 C-labeled glucose in soil
showed little difference between arabinose and xylose, but did also a tendency of a
little smaller quantity of synthesis of the former than the latter (Cheshire et al. 1969,
1971, 1973; Derrien et al. 2007). Thus, the larger proportion of arabinose in
non-forest soil than that of herbaceous plant materials might not be explained by
quantitatively larger microbial synthesis of arabinose than xylose.
100
S. Murayama and Y. Sugiura
wood of angiosperms and conifers, straw, leaves (grasses, herbs, and trees) ranges
between 0.5 and 1 (Hoch 2007; Shädel et al. 2010).
6.3.1.2 Monosaccharide Composition of Soil Polysaccharides
Few studies have reported monoaccharide composition of soil analyzed by two-step
acid hydrolysis procedure of Oades et al. (1970). Some studies cited here determined
sugar monomers released by the primary hydrolysis only of the two steps (Folsom
et al. 1974; Whitehead et al. 1975), and did not give both NEH-glucose content and
the total neutral saccharide content, but enabled calculation of the molar ratio of
GM/AX. Another study determined sugars by a high performance liquid chromatography on the combined hydrolysates obtained by two-step hydrolysis, thus the
ratio of EH-glucose/NEH-glucose was unknown (Murayama 1977a, b). Therefore,
the quantity of available data differs among Figs. 6.1, 6.3, 6.4 and 6.5. Except in
Sect. 6.5, the present article used only data for soil from the A horizon of non-arable
land, and the Ap horizon of arable land.
EH-glucose was the most abundant sugar across all soil groups (Fig. 6.3). But, the
monosaccharide composition of forest soil and forest-derived arable soil is quite
different from that of non-forest soil. The former soil is characterized by significantly
much larger proportions of EH-glucose, mannose, and by significantly much smaller
proportions of NEH-glucose, arabinose and smaller proportion of xylose. The proportions of galactose, rhamnose, fucose, and ribose are statistically not different.
6.3.1.3 Comparison of Composition Between Plant and Soil
Incorporation of woody plant materials into non-forest soil is unusual. Non-forest
soil (Fig. 6.3) is constituted of significantly larger proportion of galactose, mannose,
fucose, and rhamnose than herbaceous plants material (Fig. 6.2). Proportion of
EH-glucose is also greater in soil than plant materials at p ¼ 0.065. Some portion
of these sugars might be synthesized by microorganism in the soil as components of
polysaccharides.
It is notable that the proportion of arabinose of non-forest soil (average (av);
14.8%) is significantly much greater than that of herbaceous plant materials (av;
4.74%), though the proportion of another pentose xylose in soil (av; 15.2%) is
significantly much smaller than herbaceous plant materials (av; 31.8%)
(Fig. 6.3 vs. Fig. 6.2).
Tracer studies on microbial synthesis from
14 C or
13 C-labeled glucose in soil
showed little difference between arabinose and xylose, but did also a tendency of a
little smaller quantity of synthesis of the former than the latter (Cheshire et al. 1969,
1971, 1973; Derrien et al. 2007). Thus, the larger proportion of arabinose in
non-forest soil than that of herbaceous plant materials might not be explained by
quantitatively larger microbial synthesis of arabinose than xylose.
100
S. Murayama and Y. Sugiura