Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme V: CELL BIOLOGY AND PHYSIOLOGY Posters
1079 - Modelling fungal growth and function in
heterogeneous environments
G.P. Boswell 1 , H. Jacobs 2 , F.A. Davidson 1 , G.M. Gadd 2 &
K. Ritz 3*
1 Department of Mathematics, University of Dundee,
Dundee, DD1 4HN, Scotland, U.K. - 2 Division of
Environmental and Applied Biology, Biological Sciences
Institute, School of Life Sciences, University of Dundee,
Dundee, DD1 4HN, Scotland, U.K. - 3 Soil-Plant Dynamics
Group, Scottish Crop Research Institute, Invergowrie,
Dundee, DD2 5DA, Scotland, U.K. - E-mail:
k.ritz@cranfield.ac.uk
Modelling mycelial growth in nutritionally or spatially
heterogeneous environments is particularly challenging
since such growth is a consequence of small-scale
processes (e.g. hyphal tip extension) that are manifest at
considerably larger spatial scales (i.e. the mycelium) and
each of which has important consequences for the spatiotemporal
development of the fungus and its environment.
We describe a mathematical model that accommodates
these factors and explicitly simulates mycelial development
in heterogeneous environments at both scales. The model is
derived through the discretization of a previously
formulated partial differential equation model. The
modelled mycelial network is defined on a lattice allowing
branching and anastomosis to be explicitly observed.
Specifically, the model involves the number, location and
orientation of hyphal tips; active and inactive hyphae (i.e.
involved/not involved in translocation); internal and
external substrate concentration; and spatial organization of
substrate and habitable space. On calibrating the model
using known properties for the species Rhizoctonia solani,
information is provided on growth behaviour that is shown
to be in very good qualitative and quantitative agreement
with experimental data. Development of such an accurate
model enables important predictions to be made on the
functional consequences of fungal growth in heterogeneous
environments and the key role of translocation within
mycelia in enabling such responses.
1080 - Elements in ectomycorrhizal fungus Paxillus
involutus (Batsch ex Fr.) Fr. from various sites in
Poland
A. Brzostowski 1* , R. Kubota 2 , T. Kunito 2 , J. Falandysz 1 &
S. Tanabe 2
1 Department of Environmental Chemistry and
Ecotoxicology, University of Gdansk, 18 Sobieskiego St.
PL 80-952 Gdansk, Poland. - 2 Department of Environment
Conservation, Center for Marine Environmental Studies,
Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566,
Japan. - E-mail: abrzost@chemik.chem.univ.gda.pl
Data on metallic elements accumulation of wild growing
ectomycorrhizal fungus Poison Pax Paxillus involutus
(Batsch ex Fr.) Fr. collected from different (contaminated
and uncontaminated) ecosystems in Poland are presented.
Concentrations of essential metals (e.g. K, Na, Mg, Ca,
Mn, Fe, Cu, Zn, Ni) and other which have no apparent
essential function (e.g. Hg, Pb, Cd, Al, Ag) were
determined in caps, stalks or whole fruiting bodies. The
mushrooms were collected between 1999 and 2001 from
sites located in northern, central and southern Poland.
Dried samples were wet digested with concentrated nitric
acid in TFM vessels XP-1500 under pressure in microwave
oven (Mars 5, CEM, USA). The elements were detected
and quantified using atomic emission spectrometer with
induced coupled plasma (Optima 2000 DV, Perkin-Elmer,
USA) for some elements and with an inductively coupled
plasma-mass spectrometer (HP-4500, Hewlett-Packard,
USA). Accuracy of the method was assessed with standard
reference materials: CTA-OTL-1, IAEA-359. Poison Pax is
very common fungus and is well known to grow in
symbiosis with various trees (e.g. Pinus sylvestris) this
kind of complex research could be very useful in
understanding interactions in fungus-metal-environmenttree
system. On the other hand it may be one step further in
investigation this specimen and its metal accumulation
abilities. All these elements could be absorbed and
accumulated by different physico-chemical mechanisms
and transport systems.
1081 - Exchange processes across the ectomycorrhizal
interface: interactions between phosphate and
carbohydrate flow
H. Bücking
Centre for Environmental Research and Technology
(UFT), Applied Botany, Physiological Plant Anatomy,
Leobener Str., D-28359 Bremen, Germany. - E-mail:
heibueck@uft.uni-bremen.de
Basis of the compatible interaction between plant and fungi
in an ectomycorrhizal symbiosis is a bidirectional transfer
of nutrients across the ectomycorrhizal interface. However,
the normal flows of P and carbohydrates through the
plasma membranes into the interfacial apoplast are
calculated to be insufficient to maintain the symbiosis.
Therefore, conditions in the interface, which cause an
enhanced efflux or a decrease in the level of competing
uptake systems has been proposed by several authors (e.g.
Smith et al. 1994). Presently, we have only rare
information about a regulation of these transfer processes
occuring across this specialized interface and the
mechanisms involved in polarizing the transfer. Here, new
results are presented, which show, that the carbohydrate
supply by the photosynthetic host plant have an influence
on the P absorption by the mycobiont and the P transfer
across the ectomycorrhizal interface. By the carbohydrate
flow across the interface the P allocation between different
P pools in the mycobiont and the P efflux across the fungal
plasma membrane into the interfacial apoplast is affected.
A model system is presented, which show, in which way
the carbohydrate and P transfer might be linked and how
the exchange processes between both symbiotic partners
might be regulated. Smith SE, Gianinazzi-Pearson V,
Koide R, Cairney JWG (1994): Plant Soil 159:103-113.
Book of Abstracts 327