ECOLOGICAL STUDIES ON TILE SYMBIOSIS OF TER ITOMYCES ...

horizons of the soil
(Swift 1976), There In therefore a decline In
fungal diversity from litter to humus and mineral horizons, butt as
heret increases In the numbers in the lower depths have been found
Welter 1973)* Normally the most abundant'sporulations and'therefore
286*
the highest numbers of colonies on dilution platest occurs I In the upper
horizons (Mont6gut 1960). These fungL In the upper horizons are often
Intolerant of carbon dioxide. Other speciess more tolerant of higher
carbon dioxide levels,, and better suited by the different-conditions
of humidity and nutrition found there% may show their maximum frequency
lower, down, (Durges and Fenton 1953, l Montegut 1960, Waid 1960)o In thin
soil there are 3 species Ce2mlosporium op., Niarospora op, and
AsperSillus-terreus vh1ch only occurred at ! 50-100 cm"depth,,
Cunninghamella op, showed increasing : frequency with depth*
soil
Soil animals play an imortant part In the mixing of spores and the
(vobba and 11inson 1960)e k1ost of the general such an Aspargillues
Absidia, Cladosn2rium and Penicilliuml which have been Isol#ted here
exist an passive survival structures requiring carriage In soil water
or on, or in,, the bodies of soil animals for dispersal (Swift 1976's
Wald 19W), The vertical distribution may be affocted'by how easily
the spores can be washed down (Burgen
and'Fenton 1953)o This carriage
by'soll animaist as has been shown occurs with termites (Tables 5.2,16,
3.3,6 and 5.4.8), way account for the increased number of spores at
. 5o-100 co depth. The experiment was cmvied out at the beginning of
the rainy season* During the dry season a greater proportion of
Merotet s are found below 50 cm, than In the wet season
(Wood and
Johnson 1978) 0 and so this increase of ftmgL may be as, a result of the
previous activity of termites and other soil animals at this depth*