F. crenata forest; Fulvic Andosol); and Mount Myoko of Niigata Prefecture (MYK;
36
54
0 N 138
8
0 E; 1330 m asl; F. crenata forest; Fulvic Andosol).
Soil pH (soil/H 2 O or 1 M KCl ¼ 1:2.5) was measured with a pH meter (TPX-90i,
Toko Chemical Laboratories Co., Tokyo, Japan). The TC and total nitrogen contents
of soils were measured by means of a dry combustion method with an NC-analyzer
(NC-22A, SCAS, Tokyo, Japan). Soil samples were air-dried and sieved to <2 mm
for pH measurements and NC analysis.
7.3.1.2 AMS
14 C Dating of Sclerotia
The carbon in ectomycorrhizal fungi is derived mainly from leachate of host plants.
Most sclerotia grow to their maximum size within a few days and then become
isolated both physiologically and nutritionally (Willetts 1972). Massicotte et al.
(1992) reported that formation of C. geophilum sclerotia is initiated in 1-monthold cultures by branching, lateral growth, and subsequent septation of hyphae. With
these considerations in mind, we carried out
14 C dating of C. geophilum sclerotia to
estimate how long (in years) they had been in the soil. Sclerotia grains with
diameters >1 mm were collected from air-dried soils using sterilized tweezers.
Table 7.4 Total carbon (%)
of sclerotia, humic acid, and
soil in the ONT profile
Sample
Horizon
Carbon content (wt%)
Sclerotia (n ¼ 4)
Ah1
45.51 Æ 0.64
Ah2
41.89 Æ 1.26
E/A
40.41 Æ 0.62
Bs
37.56 Æ 1.49
Humic acid (n ¼ 4)
Ah1
53.53 Æ 0.42
Ah2
53.04 Æ 0.38
E/A
52.99 Æ 0.71
Bs
54.33 Æ 0.88
Soil (n ¼ 4)
Ah1
14.81 Æ 0.43
Ah2
9.92 Æ 0.51
E/A
8.09 Æ 0.15
Bs
7.48 Æ 0.26
Table 7.5 Total carbon (%)
of sclerotia grains in the IWK
profile
Sample
Horizon
TC content (wt%)
Sclerotia (n ¼ 3)
Ah1
48.95 Æ 0.62
Ah2
46.89 Æ 0.69
BA
42.47 Æ 0.88
Bw
40.14 Æ 1.8
Soil (n ¼ 4)
Ah1
27.80 Æ 0.46
Ah2
18.12 Æ 0.40
BA
10.46 Æ 0.43
Bw
4.46 Æ 0.25
7 Dating of Sclerotia Grains in Andosol Profiles
129
36
54
0 N 138
8
0 E; 1330 m asl; F. crenata forest; Fulvic Andosol).
Soil pH (soil/H 2 O or 1 M KCl ¼ 1:2.5) was measured with a pH meter (TPX-90i,
Toko Chemical Laboratories Co., Tokyo, Japan). The TC and total nitrogen contents
of soils were measured by means of a dry combustion method with an NC-analyzer
(NC-22A, SCAS, Tokyo, Japan). Soil samples were air-dried and sieved to <2 mm
for pH measurements and NC analysis.
7.3.1.2 AMS
14 C Dating of Sclerotia
The carbon in ectomycorrhizal fungi is derived mainly from leachate of host plants.
Most sclerotia grow to their maximum size within a few days and then become
isolated both physiologically and nutritionally (Willetts 1972). Massicotte et al.
(1992) reported that formation of C. geophilum sclerotia is initiated in 1-monthold cultures by branching, lateral growth, and subsequent septation of hyphae. With
these considerations in mind, we carried out
14 C dating of C. geophilum sclerotia to
estimate how long (in years) they had been in the soil. Sclerotia grains with
diameters >1 mm were collected from air-dried soils using sterilized tweezers.
Table 7.4 Total carbon (%)
of sclerotia, humic acid, and
soil in the ONT profile
Sample
Horizon
Carbon content (wt%)
Sclerotia (n ¼ 4)
Ah1
45.51 Æ 0.64
Ah2
41.89 Æ 1.26
E/A
40.41 Æ 0.62
Bs
37.56 Æ 1.49
Humic acid (n ¼ 4)
Ah1
53.53 Æ 0.42
Ah2
53.04 Æ 0.38
E/A
52.99 Æ 0.71
Bs
54.33 Æ 0.88
Soil (n ¼ 4)
Ah1
14.81 Æ 0.43
Ah2
9.92 Æ 0.51
E/A
8.09 Æ 0.15
Bs
7.48 Æ 0.26
Table 7.5 Total carbon (%)
of sclerotia grains in the IWK
profile
Sample
Horizon
TC content (wt%)
Sclerotia (n ¼ 3)
Ah1
48.95 Æ 0.62
Ah2
46.89 Æ 0.69
BA
42.47 Æ 0.88
Bw
40.14 Æ 1.8
Soil (n ¼ 4)
Ah1
27.80 Æ 0.46
Ah2
18.12 Æ 0.40
BA
10.46 Æ 0.43
Bw
4.46 Æ 0.25
7 Dating of Sclerotia Grains in Andosol Profiles
129