6 Wood Discoloration

24 2 Biology
mature) and non-lamellate fruit bodies. The Aphyllophorales show a number
of different types of fruit bodies whose attachment to the substrate may also
be rather distinctive: stalked, coral-like, club-like, bracket-like, resupinate, etc.
(Ryvarden and Gilbertson 1993, 1994; Schwantes 1996). Simplistically, fruit
bodies may be grouped into pileate with central stipe, bracket-like, and resupinate
(Fig. 2.17). Fruit bodies may be annual (passing after spore discharge),
biannual or perennial (every year new hymenial layers laid on the preceding
ones).
2.2.4
Fruit Body Formation
Fruit body initiation and development that occurs usually outside of the substrate
are affected by various exogenous factors: humidity, temperature, light,
nutrition, force of gravity, composition of air, and interactions with other
organisms (Schwantes 1996). Endogenous factors cover the participation of
phenol oxidases and other enzymes, cyclic adenosine monophosphate (AMP)
and genes. Fruit body formation is often promoted by conditions, e.g., warmth
in S. lacrymans, which are unfavorable for the vegetative development.
In fungi that are not tolerant to dryness, like Pholiota and Pleurotus species,
the fruit bodies frequently have a fleshy consistency and lose when drying
their function irreversibly, so that in the northern hemisphere many forest
fungi with annual fruit bodies preferentially fructify in damp-cool weather
in the autumn. Dry-tolerant fruit bodies, like in Schizophyllum commune,
continue spore production under humid conditions after dryness for many
years. Others reduce the evaporation by hairy or “varnished” surfaces, like
Inonotus and Ganoderma species. The concentric zonation of the pileus surface
(rough and smooth in the change) of Trametes versicolor is influenced by
humidity variation and the different colors of the individual zones by light and
dark phases (Williams et al. 1981). In Coprinus comatus, fruit body primordia
do not develop further without light (Jennings and Lysek 1999). Short-wave
light (UV, blue) may influence fruit body development (Schwantes 1996). The
Oyster fungus, Pleurotus ostreatus, only fruits below 16 ◦ C (Chap. 9.2), and
the less tasty subspecies P. ostreatus ssp. florida at a higher temperature. Fruit
bodies of the Winter fungus, Flammulina velutipes, appear also after snowfall.
Serpula lacrymans fruits in the laboratory after a stimulating pretreatment of
the mycelium for 3–4 weeks at the submaximal temperature of 25 ◦ C (Schmidt
and Moreth-Kebernik 1991b; Chap. 3.4). Lentinula edodes is stimulated during
its cultivation on wood in Asia by a cooling treatment. Schizophyllum commune
fruits already on simple nutrient agar at room temperature. Gloeophyllum
trabeum (Croan and Highley 1992a) and L. edodes (Leatham 1983) fructified
on defined growth media. AMP was suitable for a Coprinus species (Uno
www.taq.ir