Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme IV: POPULATION DYNAMICS AND ECOLOGY Posters
We compared interspecific interactions in fresh beech
wood and beech wood partly decayed by the primary decay
agents, Eutypa spinosa, Fomes fomentarius, Stereum
hirsutum and Trametes versicolor. The fungi used in the
experiments included five secondary decay agents,
common on beech wood in advanced decay, as well as the
aforementioned primary decayers. The experiments were
carried out using sterilised, recolonised wood and lasted for
seven months. Interactions involving secondary decayers
were affected by wood type, with outcomes changing from
complete replacement to deadlock in at least three species
combinations. Most of the secondary decayers were able to
replace some of the primary decayers. However, several of
the secondary decayers were unable to colonise sterilised
wood decayed by Trametes versicolor or Stereum
hirstutum. This lead to a new series of experiments in
which the effects of exudates from fresh and partly decayed
wood were investigated with respect to hyphal extension
rates in a larger range of secondary decay fungi. Sterilised
wood pieces were placed on 0,5% malt agar, opposite to
small plugs containing the test fungi, which showed very
variable growth responses to the various wood types. Most
species increased hyphal extension rates as response to
wood decayed by Eutypa spinosa and Fomes fomentarius,
while wood decayed by Stereum hirsutum resulted in
reduced or completely lacking growth in a majority of
species.
972 - Physiological characteristics of symbiotic fungi
associated with the seed germination of Gastrodia elata
I.P. Hong 1* , S.X. Guo 2 , T.S. Lee 3 & M.W. Lee 4
1 Division of Seri-Culture and Api-culture, NIAST, Suwon,
441-707, Korea. - 2 Institute of Medicinal Plant, Chinese
Academy of Medical Sciences, P. R., China. - 3 Department
of Biology, Incheon University, 177, Dohwa-dong, Nam-
Ku, 402-749, Korea. - 4 Department of Biology, Dongguk
University, 26, Pil-Dong 3ga, Chunggu, Seoul, 100-715,
Korea.
This study was carried out to investigate the possibility for
seeds germination of Gastrodia elata using symbiotic
fungi. Since seeds of G. elata are very small and lack an
endosperm and other nutrients, their germination is
difficult without requirement for external nutrients. Out of
twenty six isolates collected from protocorms of G. elata
and roots of native orchids inhabited in wild, two strains
(H-2 and H-21) were observed to stimulate the seed
germination of G. elata. The seed germination of G. elata
was excellent on oak tree leaves medium. The optimal
conditions for mycelial growth of symbiotic fungi were 25
°C and pH 6.0, respectively. The mycelial growth of H-2
strain was excellent on YMA medium, while h-21 was
poor on PDA medium. In case of carbon sources, the
mycelial growth of H-2 and H-21 was good on media
supplemented with glucose and dextrin, respectively.
Calcium nitrate was good for mycelial growth of H-2 strain
as a nitrogen sources, whereas urea was effective to H-21
strain.
973 - Classification of wood decay fungi isolated from
durable wood species, ekki
S. Horisawa 1* , R. Ito 2 , Y. Sakuma 3 & S. Doi 1
1 Institution of Wood Technology, Akita Prefectural
University, 11-1 Kaieizaka, Noshiro, Akita 016-0876,
Japan. - 2 Akita Wood Technology Transfer Foundation, 11-
1 Kaieizaka, Noshiro, Akita 016-0876, Japan. - 3 Biological
Resources Division, Japan International Research Center
for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba,
Ibaraki 305-0074, Japan. - E-mail: horisawa@iwt.akitapu.ac.jp
Ekki (Azobe, Bongossi; Lophira alata Banks), a native
African wood species, is known as a large durable species
and has been utilized without preservative treatment for
outdoor architectures such as bridges in EU. In Japan,
however, several bridges of ekki wood are decayed in a
short time after construction. In this study, as the first step
of the elucidation of decay in ekki wood, basidiomycetes
isolated from damaged members of ekki bridges were
classified by PCR-RFLP. Decayed wood pieces and fruit
bodies from ekki bridges were incubated on potatodextrose-agar
plates containing antibiotics. Twenty-six
isolates of basidiomycetes were obtained from different
areas in Japan. One of the isolates was identified
morphologically as Perenniporia tephropora (Mont.) Ryv.
(Loweporus tephroporus). Genomic DNAs were extracted
from isolates using the benzyl chloride method. The whole
inter specific transcribed (ITS) regions (ITS1, ITS2, and
5.8S) were amplified by PCR. The PCR products were
digested with 4 restriction enzymes to obtain RFLPs.
Restricted fragments were separated by electrophoresis in
8% of polyacrylamide gel. Comparing fragment patterns,
14 isolates were identified as P. tephropora. To obtain
further molecular information on the decay basidiomycetes,
we undertake to determine sequences of 18S rDNAs.
974 - Aspergillus section Flavi in the United States:
characterization of soil populations from agricultural
fields
B.W. Horn
National Peanut Research Laboratory, United States
Department of Agriculture, Agricultural Research Service,
P.O. Box 509, Dawson, Georgia 31742-0509, U.S.A.
Species belonging to Aspergillus section Flavi often
produce aflatoxins and cyclopiazonic acid, mycotoxins that
contaminate preharvest peanuts, corn and cottonseed. Soil
populations of A. flavus, A. parasiticus, A. nomius, A.
tamarii and A. caelatus were examined over a large
geographic area within the United States and in greater
detail within a single field. A transect was established from
New Mexico to Virginia, and species from section Flavi
showed distinct patterns in their geographic distribution. A.
flavus (large sclerotial morphotype or L strain) was the
most widely distributed species, but A. flavus var.
Book of Abstracts 293