6.5.1 Monosaccharide Composition of a Forest Soil on Mt.
Ontake from Where ECM Fungal Sclerotium Grains
Were Collected
ECM fungal sclerotia were collected from a subalpine forest soil in Yunohana pass
(2103 m a.s.l.) on Mt. Ontake, a volcano in central Japan at the beginning of August
2008 (Sugiura et al. 2017). The soil is acidic and rich in organic matter (Table 6.2).
Soil of all three horizons has a monosaccharide composition characteristic of forest
soils, namely a high molar ratio of both GM/AX and EH-glucose/NEH-glucose,
indicating that the soil has accumulated microbial polysaccharides (Table 6.2). The
O horizon was classified according to the soil taxonomy (Soil Survey Staff 2010) by
carbon content, and it is neither a plant litter layer nor an undergrowth layer.
6.5.2 Neutral Saccharides of ECM Fungal Sclerotia
Histochemical analysis has shown that fresh sclerotia produced by pure cultures of
ECM fungi contained polysaccharides (Grenville et al. 1985; Massicotte et al. 1992).
However, the content and composition of neutral saccharides in ECM fungal
sclerotia collected from forest soil were unknown until recently (Sugiura et al. 2017).
6.5.2.1 Collection of Sclerotium Grain from Soil Sample
Sclerotia of different diameter sizes of 0.20–1.0 mm, >1.0–2.0 mm, >2.0 mm were
collected by a wet sieving method (Nonoyama 2010) as described previously
(Sugiura et al. 2017). The wet sieving method cannot separate viable and dead
sclerotium, so the sclerotia collected are designated as sclerotium grains (SG). The
SG were tentatively classified as C.geophilum (Sugiura et al. 2017).
The weight of SG > 0.2 mm collected from the O, A1, and A2 horizons was 3.3,
0.91, and 0.62 g kg
À1 soil, respectively. The
14 C ages of SG collected from the O,
A1, and A2 horizons were inferred to be approximately 499–831, 1002–1698, and
2121–2798 yr. BP, respectively (Tonosaki et al. (2007, 2008). These SG were
collected from the soil profile very close to that of Sugiura et al. (2017).
6.5.2.2 Content and Composition of Neutral Saccharides in Sclerotium
Grains
The neutral saccharides of the SG were determined using the same procedure
described for soil (Sugiura et al. 2017). Neutral saccharides were substantial organic
constituent, accounting for 6.0–16% of SG by carbon content (Table 6.2). The SG
from the deepest A2 horizon, with a
14 C ages >2000 yr. BP still contained as much
as 6.0–6.6% saccharides by carbon content.
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S. Murayama and Y. Sugiura
Ontake from Where ECM Fungal Sclerotium Grains
Were Collected
ECM fungal sclerotia were collected from a subalpine forest soil in Yunohana pass
(2103 m a.s.l.) on Mt. Ontake, a volcano in central Japan at the beginning of August
2008 (Sugiura et al. 2017). The soil is acidic and rich in organic matter (Table 6.2).
Soil of all three horizons has a monosaccharide composition characteristic of forest
soils, namely a high molar ratio of both GM/AX and EH-glucose/NEH-glucose,
indicating that the soil has accumulated microbial polysaccharides (Table 6.2). The
O horizon was classified according to the soil taxonomy (Soil Survey Staff 2010) by
carbon content, and it is neither a plant litter layer nor an undergrowth layer.
6.5.2 Neutral Saccharides of ECM Fungal Sclerotia
Histochemical analysis has shown that fresh sclerotia produced by pure cultures of
ECM fungi contained polysaccharides (Grenville et al. 1985; Massicotte et al. 1992).
However, the content and composition of neutral saccharides in ECM fungal
sclerotia collected from forest soil were unknown until recently (Sugiura et al. 2017).
6.5.2.1 Collection of Sclerotium Grain from Soil Sample
Sclerotia of different diameter sizes of 0.20–1.0 mm, >1.0–2.0 mm, >2.0 mm were
collected by a wet sieving method (Nonoyama 2010) as described previously
(Sugiura et al. 2017). The wet sieving method cannot separate viable and dead
sclerotium, so the sclerotia collected are designated as sclerotium grains (SG). The
SG were tentatively classified as C.geophilum (Sugiura et al. 2017).
The weight of SG > 0.2 mm collected from the O, A1, and A2 horizons was 3.3,
0.91, and 0.62 g kg
À1 soil, respectively. The
14 C ages of SG collected from the O,
A1, and A2 horizons were inferred to be approximately 499–831, 1002–1698, and
2121–2798 yr. BP, respectively (Tonosaki et al. (2007, 2008). These SG were
collected from the soil profile very close to that of Sugiura et al. (2017).
6.5.2.2 Content and Composition of Neutral Saccharides in Sclerotium
Grains
The neutral saccharides of the SG were determined using the same procedure
described for soil (Sugiura et al. 2017). Neutral saccharides were substantial organic
constituent, accounting for 6.0–16% of SG by carbon content (Table 6.2). The SG
from the deepest A2 horizon, with a
14 C ages >2000 yr. BP still contained as much
as 6.0–6.6% saccharides by carbon content.
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S. Murayama and Y. Sugiura