The SG contained predominantly EH-glucose which account for an average of
79–80% of SG from each horizon, followed by mannose (9.4–12%), NEH-glucose
(2.2–5.8%), and galactose (3.2–4.0%). These four components comprised more than
97% of the total (Fig. 6.7).
Although they differed in
14 C age by approximately 1000 yr., SG from the A1
and A2 horizons showed similar saccharide content and composition (Fig. 6.7,
Table 6.2), suggesting that SG polysaccharides persist for a long period of time. In
addition, the SG collected from these two subsurface horizons, irrespective of size,
Table 6.2 Soil properties and neutral saccharide composition of sclerotium grains (SG) collected
from soil in Yunohana pass, Mt. Ontake (adapted from Sugiura et al. 2017)
Soil properties
Soil horizon
O
A1
A2
Soil depth
(cm)
0–13
13À28
28À55
Soil pH (H 2 O) 3.8
4.6
4.7
C content
(g kg
À1 soil)
273
127
108
N content
(g kg
À1 soil)
14.1
4.24
3.38
Soil saccharides; content and monosaccharide composition by molar ratio
Saccharide-C/
Soil-C (%)
10
8.6
7.8
(Gal + Man)/
(Ara + Xyl)
1.6
1.6
1.5
(EH-glucose/
NEH-glucose)
3.1
3.5
4.9
Sclerotium grain (SG)
Size of SG
(mm)
>2
>1À2 0.2À1 >2
>1À2 0.2À1 >2
>1À2 0.2À1
Content of SG
(g kg
À1 soil)
0.93 1.5
0.90
0.17 0.27
0.47
0.088 0.19
0.34
C content
(g kg
À1 SG)
553
562
550
446
435
462
466
410
440
N content
(g kg
À1 SG)
11.1 12.1
16.4
9.18 8.58
9.08
9.18
7.68
9.16
Saccharide-C/
SG-C (%)
16
14
12
10
7.4
7.1
6.0
6.3
6.8
Monosaccharide composition of SG by molar ratio
(Gal + Man)/
(Ara + Xyl)
15
15
25
10
10
12
9.0
7.5
14
(17)
a
(11)
(11)
(EH-glucose/
NEH-glucose)
13
14
14
51
39
37
37
40
34
(14)
(41)
(36)
(cf. Fig. 6.7)
Ara arabinose, Xyl xylose, Gal galactose, Man mannose, EH-glucose easily hydrolysable glucose,
NEH-glucose non-easily hydrolysable glucose
a Average of each horizon
6 Origin of Soil Polysaccharides, and Ectomycorrhizal Fungal Sclerotia as Sources . . .
109