| BEN |
| BOTANICAL ELECTRONIC NEWS |
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| ISSN 1188-603X |
| No. 259 October 24, 2000 | aceska@freenet.victoria.tc.ca | Victoria, B.C. |
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[This is a summary from a poster presented at the Canadian Botanical Association Annual Meeting in London, Ontario, in June 2000. The poster that I produced received the Ian and Sylvia Taylor Award for best student poster. This project is part of my undergraduate thesis project that is still underway and will be completed in June 2001. - Jen Catherall, University of Northern British Columbia, Prince George, BC, Canada V2N 4Z9]
Pterospora andromedea Nutt. (pinedrops; Ericaceae, Monotropoideae) is a curiously impressive epiparasitic species that has attracted numerous ecological and morphological investigations. This achlorophyllous species, the only member of its genus, has a complex mode of nutrition, receiving photosynthates from neighbouring trees via shared fungi.
To explore the mycorrhizal associations within its northern range, plants were sampled from 4 sub-boreal forest locations near Prince George, BC. Site-associated trees varied but included Pinus contorta, Picea spp., and Populus tremuloides. A minimum of 5 root clusters per location were collected over 10 weeks (June to August, 1999). Both epigeous and hypogeous sporocarps of the Suillus-Boletus- Rhizopogon group found within close vicinity of the sampled plants were also collected.
Mycorrhizae were assessed morphologically (light microscopy) and by molecular analysis (PCR-RFLP and DNA sequencing). All methods showed that individual root clusters (often several hundred tips) consisted of fungal monocultures. Only one fungal morphotype was characterized for all tips; this mycorrhizae produced a white mantle (sometimes mauve to darker blue), short bristle-like verrucose cystidia, no clamps, and rhizomorphs.
The three restriction endonucleases (AluI, HinfI and RsaI) used to cleave the PCR product for RFLP analysis showed no variation between the fragment patterns for the samples. DNA sequencing of the 5' end of the 28S region of the ribosomal RNA gene of the Pterospora andromedea and Pinus contorta root tips, as well as the hypogeous sporocarp, resulted in a highly similar partial sequence alignment. Submission of the fungal sequences to GenBank suggests that these fungi closely resemble Rhizopogon subcaerulescens (I.D. #AF071534).
These data are still being analysed but early results from the investigation support findings by Cullings et al. (1996). Pterospora andromedea appears to be uniquely specialized with the Rhizopogon subcaerulescens group across widely disparate regions of North America, including its northern range. This study also provides increased evidence into the probable ectomycorrhizal linkage between Pterospora andromedea, Pinus contorta and Rhizopogon subcaerulescens. The mycorrhizal specialization exhibited by Pterospora andromedea may directly impact the ability of this mycoheterotrophic plant to link with its autotrophic host(s) and ultimately its survival in changing forest ecosystems.
Reference:
Wetlands in Canada are managed very differently than in other developed nations, particularly in the United States. While American experience has been strongly oriented to a regulated permitting system and protection based on litigation, Canadian federal and provincial management to date has a strong focus on voluntary, non-regulatory action supported by policy based on sound scientific advice. The Government of Canada and four provinces (Alberta, Saskatchewan, Manitoba and Ontario) have adopted wetland management policies articulating goals and strategies for cooperation and stewardship. This is not to say regulatory actions are also not in use, in Ontario and Prince Edward Island for example provincial law regulates the use and development in and around wetlands.
In all provinces and territories in Canada a wide range of wetland conservation programs and other regulatory tools are also in place that assist in protecting wetlands and encouraging an overall no net loss perspective. These are summarized in a recent publication entitled "Wetlands and Government" available from the North American Wetland Conservation Council (Canada), Suite 200, 1750 Courtwood Cres., Ottawa, ON K2C 2B5 (e-mail: nawcc@igs.ca) or on line at http://www.cws-scf.ec.gc.ca - see publications section of this Environment Canada web site).
Why this voluntary-policy approach? Experience in Canada suggests organizations feel there are circumstances where a regulated system is appropriate as no other options exist. In some geographic areas (e.g., the Fraser Lowland and southeast Ontario) too many wetlands are degraded and too few options for voluntary action exist. However, in much of Canada a voluntary stewardship approach offering landowner incentives and support may be more effective. Despite over 20 years of costly, time consuming litigation and regulation across the USA, wetlands are still being lost. Canadians have benefitted from watching this USA experience and seek a better more successful approach here.
A major difference also lies in the constitutional authorities across the USA versus Canada. In the USA, the federal government may regulate all wetlands over a minimum size using federal water course protection legislation and other mechanisms. Small wetlands and those not associated with federally regulated waters are under state authority in most cases. Such is not the case in Canada, where most wetlands as a provincial natural resource are owned and managed under provincial jurisdiction. Only wetlands on federal lands, and in the Northern Territories generally lie under direct federal management. The federal government has laid out its commitments for wetlands through the Federal Policy on Wetland Conservation since 1991 and the Guide for Federal Land Managers under this Policy (1996).
Contact: Clayton Rubec, A/Chief Habitat Conservation, Environment Canada, Ottawa, ON K1A 0H3.
This book presents a valuable summary of current knowledge of selected aspects of bryophyte biology. It is an essential reference for bryologists and invaluable to those pursuing specialized topics in the biology of bryophytes. Few of the contributors have attempted to write for a novice; most articles are dense with specialized terminology. A glossary would have helped all readers immeasurably.
The contributions include articles on anatomy , development, and classification of hornworts (Renzaglia & Vaughn), morphology and classification of the Marchantiophyta (Crandall-Stotler & Stotler), morphology and classification of the mosses (Buck & Goffinet), origin and phylogenetic relationships of the bryophytes (Goffinet), chemical constituents and biochemistry (Mues), molecular genetic studies of moss species (Cove), control of morphogenesis in bryophytes (Christianson), physiological ecology (Proctor), mineral nutrition, substratum ecology, and pollution (Bates), peatlands: ecosystems dominated by bryophytes (Vitt), role of bryophyte-dominated ecosystems in the global carbon budget (O'Neil), population ecology, population genetics, and microevolution (Shaw), and bryogeography and conservation of bryophytes (Tan & Pocs).
Illustrations are few and reproduction of half-tones is generally poor, often resulting in grey blurred images. The illustration of Polytrichum piliferum, for example, is so blurred that it is impossible to determine the species, and acrocarpy is not clearly represented because attachment of the sporophytes is obscure; the illustrations for pleurocarpy are highly successful.
It is disappointing to see, yet again the terms haplolepideous and diplolepideous used when it is apparent that haplolepidous and diplolepidous are meant.
In summary, this book contains extremely useful articles on the current status of selected topics in bryology. It is probable that the classification systems are premature, based on inadequate data; these systems will be vastly altered when those data become available. Still, they represent useful summaries. As a reference book for students who have had education in fundamental bryology, it will be highly useful, but for beginning students, it is far too specialized.