| BEN |
| BOTANICAL ELECTRONIC NEWS |
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| ISSN 1188-603X |
| No. 205 October 16, 1998 | aceska@victoria.tc.ca Victoria, B.C. |
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Drs. Danny Fernando, John Owens and Patrick von Aderkas (University of Victoria) are happy to announce the first conifer embryo produced by in vitro fertilization. This work, which was recently reported in Theoretical and Applied Genetics (see below), was the culmination of three years of work testing and refining conditions in the search for the best way to grow male and female structures of Douglas fir in Petri dishes. The assisted conception was brought about when germinated pollen tube penetrated the eggs, and released gametes, one of which fused with the egg nucleus. Early stages of embryo development occurred in vitro. The proof of these events was provided in a series of sections of plastic-embedded material. We have yet to produce a tree, but the prospect of consummating sexual union in vitro offers intriguing possibilities, especially in regard to hybridization.
This was borne out by a subsequent study, to be published in TAG (in press) by Nicole Dumont-BeBoux and coworkers in which it was shown that there is no barrier to delivery of gametes between any of the genera of the Pinaceae attempted. These included: i) Sitka spruce into either noble hybrid larch, Douglas fir or western white pine; ii) western white pine into Douglas fir; or iii) western larch into western white pine. Pollen tube penetration occurred in all crosses and was verified by histological study. Gamete delivery occurred in the spruce/larch cross. The conclusion from our work is that prezygotic sexual barriers to reproduction do not exist in vitro. In vitro fertilization could be used to cross species that are not currently possible to cross by conventional breeding methods. It also provides a method to study the processes of pollen attraction, gamete delivery and fertilization in controlled environments. Eventually, we should be able to elucidate some of the underlying mechanisms in gymnosperm reproduction.
Dr. Patrick von Aderkas
Graduate Centre for Forest Biology
University of Victoria
Victoria BC Canada V8W 3N5
pvonader@uvvm.uvic.ca
telephone: 1 250 721 8925
FAX: 1 250 721 7120
The article defines current technical terms used in the field of restoration ecology and reviews restoration efforts in restoration of wetlands:
The main steps in restoring species-rich oligotrophic wet meadows on formerly fertilized grassland or arable land are the removal of excessive nutrients, the correction of water table and the re-introduction of species.
Restoration of ombrogenous bog depends on the successful reestablishment of suitable hydrological conditions which will often give rise to a spontaneous recolonization by typical bog species; details of the artificial re-introduction of Sphagnum species are also given.
In restoring riverine ecosystems, for example by recreating meanders, apart from controlling flood hazards, consideration will have to be given primarily to a variable design but consequences on the sediment transport should be carefully studied. Vegetation can in most cases be left to natural succession, whereas providing unhindered up- and downstream migration and resting places for animals is an important issue.
The paper cites about 130 references related to this topic.
I first met Dr. Pielou in Victoria the mid 1970's when she was invited to participate in a conference on mathematics in biology. I vividly remember her lecture. Early in the morning before the lecture, Chris Pielou went to the beach and picked several species of seaweeds that she used in her lecture. Mathematical applications become real and we, the audience, were able to relate abstract topics with biological objects. We all were impressed how clearly Dr. Pielou could communicate complex and complicated ideas.
Dr. Pielou's demonstrates this quality in her recent book "Fresh Water." In twelve chapters, Chris Pielou follows the water cycle and all its stages. Rivers, lakes, underground and soil water, water in plants, frozen water, and water in wetlands, are all subjects covered in Dr. Pielou's book. The book is an excellent synthesis of physical geography, soil science, climatology, hydrology, hydrobiology, plant physiology, and all other fields that relate to water.
The book describes "natural history" of water. It provides a key to the understanding of many processes and features around us. Dr. Pielou's writing style is clear and captivating and the "Prologue" is a literary masterpiece in its own merit. The book has plenty of unobstructive footnotes and numerous reference citations. The book contains all, or almost all, what each of us should know about water. Get the book and read it! You will be glad you did.
The database, funded by the Netherlands Science Foundation (NWO) and produced with the package BRAHMS (Denis Filer, Oxford, England), combines all known type specimens of the four Dutch herbaria: Amsterdam (AMD), Leiden (L), Utrecht (U), and Wageningen (WAG). This type of cooperation among herbaria is unique, as is the fact that digital images are available of most type specimens. The database presently holds 40,000 records and 30,000 images.
Visit HTTP://RULRHB.LEIDENUNIV.NL (or http://132.229.92.132/)
This netsite, produced by the Expert Centre for Taxonomic Identification, ETI, Amsterdam, opens with a menu. The first choice, 'search the database', provides a form from which very versatile queries can be made. Plant names can be used as key words, as well as geography, vernacular names, collectors, etc. The hits are presented in a spread sheet, arranged alphabetically by the accepted name; basionyms are shown in the right hand columns. Double clicking on a name will provide full label details and show a photo of the type specimen(s). Double clicking on the photo will provide an enlarged image on your screen.
The main menu also provides an option to order a CD-ROM of the complete database (with only thumb-nail images of the specimens). It is also possible to order CD-ROMs with a subset of the database and with high resolution photos.