T-RFLP analysis to survey the ectomycorrhizal fungal community, using the methodology described in Chap. 2.2.1.
3.3.1.2 Soil pH and Exchangeable Aluminum Content
Sclerotia contain a relatively high concentration of aluminum, and the formation of
sclerotia has been reported to be regulated by the quantity of exchangeable aluminum and active aluminum in the soil, regardless of soil type (Watanabe et al. 2002).
To obtain an index of soil acidity, we measured pH using 1 M KCl and determined
the exchangeable aluminum content of soil. Sclerotia grains were isolated from soil
samples and then tested for pH (KCl) according to the method of Bertsch and Bloom
(1996). Sclerotia-free and sclerotia-containing soil samples were prepared. Isolated
sclerotia grains were crushed with a mortar and pestle and then mixed with soil
samples prior to KCl extraction. The exchangeable aluminum content was determined for both sclerotia-containing and sclerotia-free soils using a plasma atomic
emission spectrometer (ICPE-9000, Shimadzu Corp, Kyoto, Japan).
3.3.2 Results and Discussion
3.3.2.1 Ectomycorrhizal Fungal Community Profiles of Sclerotia, Soil
Mesofauna, and Soil Samples
Sclerotia were not detected in soil samples from Minamiosawa, perhaps due to the
low soil acidity (pH ¼ 6.11 Æ 0.21; Table 3.3), because it has been suggested that
low soil pH is important for sclerotia formation (Aycock 1966). Because no sclerotia
were collected, the T-RFLP analysis of sclerotia was not conducted for this site. For
the remaining study sites, the dominant sclerotia-forming fungi were identified as
Table 3.3 Exchangeable aluminum content in soil with and without sclerotia. Data are
mean Æ standard errors (Amasya 2015)
Soil pH
(KCl)
(n ¼ 9)
Sclerotia
Soil Al Ex (g kg
À1
)
Diameter
(mm) (n ¼ 54)
Weight density
(mg/g) (n ¼ 54)
Sclerotia-free
(n ¼ 27)
With added
sclerotia
Akita
4.76 Æ 0.02
0.98 Æ 0.21
0.05 Æ 0.01
0.57 Æ 0.03
0.61 Æ 0.02
(n ¼ 6)
Nagano 4.17 Æ 0.03
1.07 Æ 0.29
0.07 Æ 0.01
0.59 Æ 0.03
0.64 Æ 0.003
(n ¼ 3)
Chokai 3.88 Æ 0.03
1.33 Æ 0.62
0.11 Æ 0.02
0.69 Æ 0.04
0.76 Æ 0.04
(n ¼ 9)
Iwaki
3.44 Æ 0.03
2.73 Æ 1.13
0.29 Æ 0.04
0.87 Æ 0.02
0.97 Æ 0.01
(n ¼ 27)
3 Relationships Between Soil Mesofauna, Ectomycorrhizal Fungi, and Sclerotia in. . .
51
3.3.1.2 Soil pH and Exchangeable Aluminum Content
Sclerotia contain a relatively high concentration of aluminum, and the formation of
sclerotia has been reported to be regulated by the quantity of exchangeable aluminum and active aluminum in the soil, regardless of soil type (Watanabe et al. 2002).
To obtain an index of soil acidity, we measured pH using 1 M KCl and determined
the exchangeable aluminum content of soil. Sclerotia grains were isolated from soil
samples and then tested for pH (KCl) according to the method of Bertsch and Bloom
(1996). Sclerotia-free and sclerotia-containing soil samples were prepared. Isolated
sclerotia grains were crushed with a mortar and pestle and then mixed with soil
samples prior to KCl extraction. The exchangeable aluminum content was determined for both sclerotia-containing and sclerotia-free soils using a plasma atomic
emission spectrometer (ICPE-9000, Shimadzu Corp, Kyoto, Japan).
3.3.2 Results and Discussion
3.3.2.1 Ectomycorrhizal Fungal Community Profiles of Sclerotia, Soil
Mesofauna, and Soil Samples
Sclerotia were not detected in soil samples from Minamiosawa, perhaps due to the
low soil acidity (pH ¼ 6.11 Æ 0.21; Table 3.3), because it has been suggested that
low soil pH is important for sclerotia formation (Aycock 1966). Because no sclerotia
were collected, the T-RFLP analysis of sclerotia was not conducted for this site. For
the remaining study sites, the dominant sclerotia-forming fungi were identified as
Table 3.3 Exchangeable aluminum content in soil with and without sclerotia. Data are
mean Æ standard errors (Amasya 2015)
Soil pH
(KCl)
(n ¼ 9)
Sclerotia
Soil Al Ex (g kg
À1
)
Diameter
(mm) (n ¼ 54)
Weight density
(mg/g) (n ¼ 54)
Sclerotia-free
(n ¼ 27)
With added
sclerotia
Akita
4.76 Æ 0.02
0.98 Æ 0.21
0.05 Æ 0.01
0.57 Æ 0.03
0.61 Æ 0.02
(n ¼ 6)
Nagano 4.17 Æ 0.03
1.07 Æ 0.29
0.07 Æ 0.01
0.59 Æ 0.03
0.64 Æ 0.003
(n ¼ 3)
Chokai 3.88 Æ 0.03
1.33 Æ 0.62
0.11 Æ 0.02
0.69 Æ 0.04
0.76 Æ 0.04
(n ¼ 9)
Iwaki
3.44 Æ 0.03
2.73 Æ 1.13
0.29 Æ 0.04
0.87 Æ 0.02
0.97 Æ 0.01
(n ¼ 27)
3 Relationships Between Soil Mesofauna, Ectomycorrhizal Fungi, and Sclerotia in. . .
51