Keywords Specific gravity · Elemental composition · Chemical properties ·
CHNO · FTIR spectrometry · C-NMR ·
27 Al-NMR · XRD · SEM/EDS · ICP-OES ·
ICP-MS
5.1 Introduction
Sclerotia grains are the resting bodies of some ectomycorrhizal fungi. Cenococcum
geophilum Fr. is one of the most common and worldwide fungi of Ascomycota
(LoBuglio et al. 1996). Kumada and Hurst (1967) reported that sclerotia of Cg Fr
which tend to be black, spherical, and 1–2 mm in diameter are the source of the green
fraction of P-type humic acid, known as “Pg.” The forest near Asadaira, Mt. Myoko,
Niigata Prefecture, Japan, is primarily composed of Fagus sylvatica Pendula, and
the soils contain a large amount of sclerotia grains (Kumada 1987).
Sclerotia grains are considered to be one of the precursors of the humic acid “Pg”
fraction (Kumada and Hurst 1967). Purified humic acid “Pg” (Watanabe et al. 1996)
extracted from soils in Asadaira, Mt. Myoko, Japan, showed an elemental composition similar to the sclerotium grains. Watanabe et al. (1996) reported that the G1
fraction contained larger amounts of alkyl chains, whereas the G2 fraction contained
larger amounts of polysaccharides, the chemical features of carbon species in
sclerotium grains were more likely to be those of combined G1 and G2 fractions.
Further chemical analyses of the structure of sclerotia grains will provide a better
understanding of the formation and structure of humic substances in acidic soils in
relation to the behavior of metals, especially aluminum. In this chapter, we discuss
our method for preparation of standard samples for quantitative determination of the
major and trace element contents of sclerotia grains. We also examined the carbon
species present in sclerotia grains in order to understand their chemical
characteristics.
5.2 Preparation of Standard Samples
The sclerotia grains used in this study were collected from the 3A horizon (26–34 cm
depth) of the Fulvic Andosol profile (WRB/FAO-Unesco) on Mt. Myoko
(36
54
0 00
00 N, 138
08
0 25
00 E, 2190 m elevation) in July 2002 and June 2003. As
shown in Fig. 5.1 and Table 5.1, the 3A horizon corresponds to a buried A horizon
beneath a 2C horizon, which is a tephra layer (Koyaike ash-c) derived from the
eruption of Yakeyama volcano in 950 Æ 80 years BP (Hayatsu et al. 1994). The site
was selected based on the study that reported that the source of the green fraction of
P-type humic acid in soils, known as “Pg,” could be sclerotia of Cenococcum
geophilum Fr. (Kumada and Hurst 1967), and the site was known to be rich in
sclerotia grains (Kumada 1987). We decided to prepare sclerotia grains collected
from the buried A horizon as standard samples, in terms of advantage of protection
78
B. Oyuntsetseg et al.
CHNO · FTIR spectrometry · C-NMR ·
27 Al-NMR · XRD · SEM/EDS · ICP-OES ·
ICP-MS
5.1 Introduction
Sclerotia grains are the resting bodies of some ectomycorrhizal fungi. Cenococcum
geophilum Fr. is one of the most common and worldwide fungi of Ascomycota
(LoBuglio et al. 1996). Kumada and Hurst (1967) reported that sclerotia of Cg Fr
which tend to be black, spherical, and 1–2 mm in diameter are the source of the green
fraction of P-type humic acid, known as “Pg.” The forest near Asadaira, Mt. Myoko,
Niigata Prefecture, Japan, is primarily composed of Fagus sylvatica Pendula, and
the soils contain a large amount of sclerotia grains (Kumada 1987).
Sclerotia grains are considered to be one of the precursors of the humic acid “Pg”
fraction (Kumada and Hurst 1967). Purified humic acid “Pg” (Watanabe et al. 1996)
extracted from soils in Asadaira, Mt. Myoko, Japan, showed an elemental composition similar to the sclerotium grains. Watanabe et al. (1996) reported that the G1
fraction contained larger amounts of alkyl chains, whereas the G2 fraction contained
larger amounts of polysaccharides, the chemical features of carbon species in
sclerotium grains were more likely to be those of combined G1 and G2 fractions.
Further chemical analyses of the structure of sclerotia grains will provide a better
understanding of the formation and structure of humic substances in acidic soils in
relation to the behavior of metals, especially aluminum. In this chapter, we discuss
our method for preparation of standard samples for quantitative determination of the
major and trace element contents of sclerotia grains. We also examined the carbon
species present in sclerotia grains in order to understand their chemical
characteristics.
5.2 Preparation of Standard Samples
The sclerotia grains used in this study were collected from the 3A horizon (26–34 cm
depth) of the Fulvic Andosol profile (WRB/FAO-Unesco) on Mt. Myoko
(36
54
0 00
00 N, 138
08
0 25
00 E, 2190 m elevation) in July 2002 and June 2003. As
shown in Fig. 5.1 and Table 5.1, the 3A horizon corresponds to a buried A horizon
beneath a 2C horizon, which is a tephra layer (Koyaike ash-c) derived from the
eruption of Yakeyama volcano in 950 Æ 80 years BP (Hayatsu et al. 1994). The site
was selected based on the study that reported that the source of the green fraction of
P-type humic acid in soils, known as “Pg,” could be sclerotia of Cenococcum
geophilum Fr. (Kumada and Hurst 1967), and the site was known to be rich in
sclerotia grains (Kumada 1987). We decided to prepare sclerotia grains collected
from the buried A horizon as standard samples, in terms of advantage of protection
78
B. Oyuntsetseg et al.