I am an associate professor working on allelopathy and spruce (Picea abies)
forests natural regeneration. Particularly, my research work has been
focused on the allelopathic phenomena inhibiting spruce natural
regeneration, which have been investigated by in situ and in vitro
experimental studies. Some of our results are presented for your information
in brief in the end of this letter, together with a list of publications
issued until now from this
work.
Last year (from September 1992 to September 1993) we received a Greek
postgraduate student, who carried out a research work on the effects of
phenolic acids on mycorrhizal fungi. He demonstrated rigorous mind and
obtained very interesting results, giving rise to two publications (in Acta
Botanica Gallica and Journal of Chemical Ecology). This year, he has a good
chance to obtain a Ph. D. grant (2 years, eventually a third one). He should
study allelopathy in Mediterranean forest ecosystems.
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*We think that if a Greek Laboratory is interested it could be advisable to
* *begin a co-operation, by means of a co-tutorial thesis. *
*
* *****************************************************************************
If you are interested (or if you know a greek laboratory susceptible to be
interested) please reply as soon as possible (by fax or internet) because we
have to fill out before May, 25 an application form in order to obtain the
fellowship and we must define together a detailed research program.
Many thanks,
François Pellissier
YOU CAN REPLY IN E-MAIL: pellissier@univ-savoie.fr
MAIL: UNIVERSITY OF SAVOIE
Altitude Ecosystems Dynamics
Dr. Francois PELLISSIER
Scientific Campus
73376 LE BOURGET DU LAC
FRANCE
FAX: 79 75 88 80
PHONE: 79 75 88 69
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SUMMARY OF RESEARCH ACTIVITIES ON ALLELOPATHY AND FOREST REGENERATION
Subalpine spruce (Picea abies) forests in the northern Alps are facing
serious problems in natural regeneration. Field experiment has shown that
competition between two dominant undergrowth species, Vaccinium myrtillus
and Athyrium filix-femina, and spruce seedlings occurs even when nutrients
and light are not restrictive.[1,2] Experimental seedlings indicated that
humus restricts spruce germination (less than 1% germinated)and is also
responsible for a substantial loss of seedlings (at least 50%) from the
first year onwards.[3] In vitro spruce germination and mycorrhizal fungi
growth tests were realised with V. myrtillus, A. filix-femina and P. abies
leaves aqueous extracts and humic solutions.[4,5] The most important
inhibitions were performed with A. filix-femina foliar
extracts and its humic solution. Analysis of foliar material identified four
phenolic acids synthesised by spruce needles and leaves of the two common
undergrowth species. Those compounds were also present in humic solution at
10-5 molar and were then selected for a second identical series of in vitro
bioassays. In this way, phytotoxicity of phenolic molecules was expressly
stated. Interferences of these phenolic acids on metabolism mechanisms were
explained by means of a polarographically oxygen electrode: they seem to act
as uncoupliers.[6,7,8] A last in situ experimental seedling, with and
without humic solutions concluded this work : it confirmed the laboratory
results.[9]
BIBLIOGRAPHY
[1] PELLISSIER F., 1990. Allélopathie, mycorhization et les difficultés de
la régénération naturelle dans les pessières subalpines. Ph. D. Thesis,
University of Grenoble I, 100.
[2] ANDRE J., GENSAC P., PELLISSIER F. et TROSSET L., 1987. Régénération
des peuplements d'épicéa en altitude: recherches préliminaires sur le rôle
de l'allélopathie et de la mycorhization dans les premiers stades du
développement. Revue d'Ecologie et de Biologie du Sol, 24, 3, 301-310.
[3] PELLISSIER F. et TROSSET L., 1992. Les difficultés de régénération
naturelle des pessières subalpines: prédation des graines au sol et blocages
dus à l'humus. Annales des Sciences Forestières, 49, 383 - 388.
[4] PELLISSIER F., 1993. Allelopathic inhibition of spruce germination.
Acta Oecologica. 14, 2, 211-218.
[5] PELLISSIER F. et TROSSET L., 1989. Obstacle allélopathique à la
germination de graines d'épicéa et à la croissance de trois champignons
ectomycorhiziens de cette essence. Acta Biologica Montana, IX, 153-160.
[6] PELLISSIER F., 1993. Allelopathic effect of phenolic acids fromhumic
solutions on two spruce mycorrhizal fungi : Cenococcum graniforme and
Laccaria laccata. Journal of Chemical Ecology, 19, 10, 2105-2114.
[7] PELLISSIER F. and TROSSET L., 1989. Effect of phytotoxic solutions on
the respiration of mycorrhizal and non-mycorrhizal spruce roots (Picea abies
(L.) Karst.). Annales des Sciences Forestières, 46 (suppl.), 731s-733s.
[8] BOUFALIS A., PELLISSIER F. and TROSSET L., 1994. Cenococcum geophilum
and Laccaria laccata growth with phenolic acids. Acta Botanica Gallica, in
press.
[9] PELLISSIER F., 1994. Effects of phenolic compounds in humus on the
natural regeneration of spruce. Phytochemistry, in press.
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