RARE PLANT SYMPOSIUM - UBC VANCOUVER, B.C. - OCTOBER 17, 1998

What: "Living on the Edge: a symposium on the rare plants of British Columbia"

An afternoon symposium addressing some of the issues surrounding the rare plants and plant communities of BC. Topics will include rare mosses, liverworts, ferns and aquatics, as well as the rare Coastal Douglas fir zone grasslands and vascular plant conservation issues in the Fraser Valley. Among the invited speakers will be Adolf Ceska of the Conservation Data Centre, Hans Roemer of the Ministry of Environment, Wilf Schofield and Fred Ganders from the UBC Department of Botany, Brenda Costanzo from the University of Victoria Biology Department, and others.

The symposium will also feature a showing of original paintings by Oluna Ceska and Lesley Bohm illustrating British Columbia's flora.

When: October 17, 1998 1:00-6:00 pm

Where: University of British Columbia, Vancouver, B.C., Bioscience 2000, 6270 University Blvd. (next building west of the bookstore).

Who: Patrick Williston and Kelly Bannister are organizing this symposium jointly supported by the Botany Graduate Students Society and the NPSBC - Native Plant Society of British Columbia.

How much: Student $5. Regular $8 at the door.

Need more information? Contact Patrick Williston (604)-266-7903 or patrickw@interchange.ubc.ca

THE TWISTING TALE OF THE BLACK TRUFFLE (TUBER MELANOSPORUM)

Of the ten species of European truffles (fungi of the genus Tuber, phylum Ascomycota), the Black Truffle, Tuber melanosporum, is among the most valuable. Its taste and perfume has made it famous for connoisseurs, and no restaurant can achieve true distinction unless it includes it in its menu. An interesting fact is the differences displayed by the fungus according to its geographical origin: a specialist can tell whether a truffle comes from one place or another. We attempted to determine which factor, either nature or nurture (i.e. genetic or environmental grounds) was responsible for this variation by assessing the genetic diversity on a sample as large as possible (Bertault et al. 1998). More than 200 ascocarps were investigated for microsatellite and Random Amplified Polymorphic DNA (RAPD) variability, and the relation between this variability and the geographic distance between truffles was tested.

Two striking results appeared:

1. We found out that the Black Truffle displayed an amazingly low degree of genetic diversity, that could not compare to that found in some other Tuber species (e.g., the Summer Truffle, Tuber aestivum). This result confirms those previously found on small samples of various truffle species (see e.g., Gandeboeuf 1997).
2. We could not relate the little amount of genetic diversity found with the geographic distance between samples. In other words, truffles far away from one another were not more genetically diverse than truffles coming from the same place.

These two facts enabled us to hypothesize that the Black Truffle had experienced a drastic reduction in number during the last glacial period that ended some 10,000 years ago. Indeed, the fungus' range has probably been restricted to a few refugia (maybe even only to a single one) in its southernmost limit of distribution. During this period, it could thus have lost almost all of its former genetic diversity, and a rapid recolonization of its previous range would not have allowed the isolates to differentiate.

The Black Truffle ripens in winter, is very sensitive to frost, and suffers more from cold than does the Summer Truffle. The Summer Truffle is dormant through the winter and it has higher tolerance to cold. During the glacial period it might have occupied a wider range than the Black Truffle did, and it retained higher genetic variation.

According to our findings, two conclusions can be drawn for truffle growing and collecting:

1. The absence of genetic differentiation for neutral and anonymous DNA markers led us to advise against any program dealing with determining subspecies or cross-breeding of different strains in order to improve the genetic content of the truffles, since they all seem to be genetically identical regardless of the place where they were sampled.
2. A special attention should be paid to the environmental factors (e.g., soil, climate & associated tree species) that seem to rule the taste and perfume of the Black Truffle.

References:

Bertault, G., Raymond, M., Berthomieu, A., Callot, G. & Fernandez, D. 1998.

Trifling variation in truffles. Nature, 394: 734.

Gandeboeuf, D., Dupre, C., Roeckel-Drevet, P., Nicolas, P. et Chevalier, G. 1997.

Grouping and identification of Tuber species using RAPD markers. Canadian Journal of Botany, 75: 35-45.

Bertault, G., Raymond, M., Berthomieu, A.

Institut des Sciences de l'Evolution, Laboratoire Genetique et Environnement Cc 65, Universite Montpellier II, 34095 Montpellier Cedex 05, France.

Callot, G.

Institut des Sciences du Sol, Institut National de la Recherche Agronomique, Place Viala, 34060 Montpellier Cedex 01, France.

Fernandez, D.

Laboratoire de Phytopathologie Comparee, ORSTOM, BP 5045, 34032 Montpellier Cedex 01, France.

ERYTHRONIUM GRANDIFLORUM: ECOLOGY & ETHNOBOTANY

I would like very much to thank the countless wonderful, altruistic botanists and naturalists who took the time to contact me via my "Erythronium hotline" with site information or who otherwise took an interest in my project. I finished and defended my thesis in summer 1998.

Thesis abstract:

This research examined a single bulb-bearing edible plant species, yellow glacier lily (Erythronium grandiflorum). Three main approaches to the research were taken:

1. an ecological study, to determine the general habitat requirements of the species in western Canada, and to investigate the nature of vegetative reproduction in the species;
2. an ethnobotanical study, consisting of an extensive literature search for all recorded First Nations' uses of the species (in Canada and elsewhere), in addition to interviews with contemporary Interior Salish elders;
3. a nutritional study, examining in detail the nutritional characteristics of the bulbs, and particularly changes in the carbohydrate content over the course of the growing season and with different types of treatments.

The ecological data indicate that Erythronium grandiflorum is more abundant in meadow environments or sites with deciduous cover than in sites with coniferous forest cover. Flowering plants tended to be more abundant and robust at low elevation meadows, while seedlings and juveniles were disproportionately represented at high elevation meadows. Decreased juvenile success in the low-elevation meadows may be related to relatively high litter from shrubs and grasses. Experimental data indicate that appendages on the bulbs, which persist as remnants of previous years' bulbs, can act as vegetative propagules if mechanically separated. In addition, both bulbs and appendages were successfully transplanted over a two-year period from a subalpine meadow to a very different habitat type, 1500 m lower in elevation.

The ethnobotanical review confirms that the species was traditionally a highly significant root resource for northern plateau peoples, particularly the Secwepemc and Nlaka'pamux peoples, for probably thousands of years. These peoples collected, stored, and traded large quantities of the bulbs, and the traditional processing strategies generally included drying and pit-cooking. People developed a detailed ecological understanding of the species, and practiced active resource management strategies.

Nutritional results indicated a carbohydrate-rich food resource, with the main storage carbohydrate consisting of starch (not inulin or other fructan) through most of the growing season. There are significant quantities of sugars (including fructooligosaccharides) present at the beginning of the growing season, but starch increases rapidly and peaks (along with overall food value) in the early (green) fruit stage of growth. For bulbs at the fruiting stage, drying markedly increases sugars in the bulbs relative to starch, while pit-cooking the dried bulbs does not have significant effects on relative amounts of carbohydrates. However, pit-cooking has important qualitative effects on the appearance, taste, and possibly storage properties of the bulbs, as well as representing an efficient processing strategy.

I argue that traditional harvesting and management strategies practiced by First Nations people (including tilling, thinning, replanting of appendages, and landscape burning) mean that the ecology and ethnobotany of the species cannot be considered in isolation. Based on previous ecological and ethnoecological work on this and similar species, it seems likely that yellow glacier lily is adapted to a periodic, moderate disturbance regime, which traditional practices may have mimicked or enhanced.

Loewen, D.C. 1998.

Ecological, Ethnobotanical, and Nutritional Aspects of Yellow Glacier Lily, Erythronium grandiflorum Pursh (Liliaceae), in Western Canada. M.Sc. Thesis, Department of Biology, University of Victoria, Victoria, BC. 214 pages.