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Abstract

Hazel (Corylus avellana L.) seedlings inoculated with the Perigord black truffle
fungus (Tuber melanosporum Vitt.) are being planted in Tasmania in an attempt to
culture truffles. Competition from other ectomycorrhizal fungi has a significant
impact on truffle production in Europe and can be expected to have some effect on
the Tasmanian industry. This thesis examines ectomycorrhizal fungi occurring in
Tasmania with respect to their ability to form mycorrhizas with hazel and compete
with T melanosporum under various soil treatments.
Stands of hazel previously established for nut production or as ornaments were
surveyed for the sporocarps of ectomycorrhizal fungi. Several species were found
;
including species that are new either to Australia or Tasmania. The endemic
species Descomyces albus (Klotzsch) Bougher & Castellano and
Podohydnangium sp., previously thought to. be Eucalyptus specific were. fruiting
under hazel.
T melanosporum occurs naturally on calcareous soils in Europe. Truffieres in
Tasmania are heavily limed to create a calcareous soil environment. The response
of selected introduced and endemic ectomycorrhizal fungi to applied lime was
studied in a glasshouse experiment. Some of the endemic species, which would
normally inhabit acidic soils, were unable to survive high rates of lime application
and therefore should not pose a threat to the truffle industry. The introduced
species were generally more tolerant to lime application.
A subsequent glasshouse experiment sought to separate the effects of pH and
calcium on colonisation by T melanosporum. Seedling hazels were inoculated
with T melanosporum. After twelve months, they were transplanted using soil
amended with fourteen rates of either CaCO3 , CaSO4, or MgCO3 . The seedlings were then exposed to spores of two endemic fungal species. Applied CaCO 3 and
MgCO3 increased level of colonisation by T melanosporum, whereas CaSO4 had
little or no effect. Soil pH appears to have a stronger influence on colonisation by
T melanosporum than the level of applied or exchangeable calcium. Colonisation
by endemic species was low and sporadic across all treatments.
Another glasshouse experiment of similar design to that above was established to
observe the effect of lime and phosphorus interaction. Applied lime significantly
increased the level of colonisation of T melanosporum, but phosphorus had no
effect, even at very high rates of application (150 mg P / Kg soil).
A commercial truffiere was surveyed for the level of colonisation by
T melanosporum and other ectomycorrhizal fungi.
Descriptions were compiled of the mycorrhizas of fungal species found in the
glasshouse and field experiments to assist in their future identification.
The morphological identification of Tuber mycorrhizas was confirmed using PCR
and RFLP of DNA extracted from single mycorrhizal tips.

Item Type:	Thesis - PhD
Authors/Creators:	Brown, Daryl
Keywords:	Ectomycorrhizas, Truffles, Truffieres, Truffle culture, Fungi
Copyright Holders:	The Author
Copyright Information:	Copyright 1998 the Author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s).
Additional Information:	No access until 31/7/2003. Thesis (Ph.D.)--University of Tasmania, 1998. Includes bibliographical references
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