A Survey of Lichens and Bryophytes in White Spruce, Picea glauca, Tree Islands on a Calcareous Beach Ridge in Northeastern Manitoba

Studies on the diversity of lichens and bryophytes in northern ecosystems have focused on open tundra and boreal forests. Krummholz tree islands have received little attention. This study examined species’ diversity of lichens and bryophytes among islands of White Spruce trees in northern Manitoba. Thirty-three species were found in the tree islands with 11 additional species forming the understorey layer. The trees were dominated by epiphytic lichens and the understorey was dominated by pleurocarpous mosses. The most common lichens were widespread species. Rare lichens in the study area included Protopannaria pezizoides and Alectoria nigricans growing in the shaded interior of the tree islands. The age and density of the tree islands may produce habitat conditions different from those in mature White Spruce boreal forests. Comparative studies between White Spruce krummholz and other White Spruce stands are needed

Molecular evolution, identification and epidemiology of North American species of a root-infecting fungus, Armillaria

Armillaria (Fr.:Fr.) Staude is a genus of root-infecting fungal pathogens which cause disease in forests and orchard plantations. Biological species of Armillaria are identified by sexual incompatibility mating interactions. Epidemiological studies of North American species of Armillaria indicated that some are saprotrophic, some mycotrophic, and others are necrotrophic pathogens often producing death of the host. Stress of the host tree is often considered a critical factor in disease development. -- Three objectives to this study examined different aspects of the pathogenicity of Armillaria. The first was to estimate phylogenetic relationships among North American biological species (NABS) of Armillaria. This allowed inference of inheritance of pathogenic traits among species. The second was to develop species-specific molecular markers for NABS Armillaria. This would provide a method of identification for pathogenic species. The third was to examine disease development of Armillaria inoculum using different types and degrees of stress inflicted on the host tree. Molecular techniques were employed to examine the first two objectives. The third objective involved a field inoculation trial with two Newfoundland isolates of A. ostoyae. -- This study is consistent with previous phylogenetic hypotheses concerning relationships among species of Armillaria. Phylogenetic analysis of randomly amplified DNA regions of unknown function provided strong support for intraspecies clustering. Most NABS Armillaria were resolved using four anonymous nucleotide sequences combined within a single data set. There was stong support for the clustering of NABS I and II, as well as NABS III and VII. Isolates of NABS V showed sequence polymorphism. -- Species-specific molecular markers were developed for most NABS Armillaria. PCR amplification using a combination of different random primer sets in each of the reaction mixtures, yielded species size-specific bands on an agarose gel for each of NABS I, II and VI. A common band was found specific for NABS III and VII. Although NABS V, IX and X contained less variation, 10 nucleotide primers could be used to confirm their identity. Results from inverse PCR suggested that secondary DNA structure and primer/template competition played a significant role in determining species-specificity with SWAPP 10 nucleotide primers. -- Results from the field inoculation trials suggested that two years was sufficient time to allow forest managers to make informed decisions regarding stand management. Host stress appeared to influence Armillaria root disease development. The black spruce plantation had more infection than the naturally regenerated stand. There was more disease in the balsam fir thinned stand than the un-thinned stand. Significant correlation between infection and above ground tree symptoms occurred in a very severely defoliated balsam fir sawfly plot only. Well-drained sandy soil seemed to increase the aggressiveness of the Armillaria isolate used as inoculum. -- The utilization of molecular techniques, combined with knowledge of ecological processes, would greatly enhance the efficiency of forest management

Effects of damage-induced and developmental changes of white birch (Betula papyrifera Marsh.) on populations of birch casebearer (Coleophora serratella L.) (Lepidoptera: Coleophoridae)

Insects feeding on a plant may induce changes within the leaves which affect success of insects subsequently feeding on that plant. The objective of this study was to demonstrate if birch casebearer feeding on birch leaves induced changes in the tree that would deter subsequent feeding by the same insect species. -- White birch trees were divided into four treatment groups of five trees each. Treatments consisted of birch leaves being severely damaged by insect feeding, lightly damaged by insect feeding, mechanically damaged with no insects present, and control with neither type of damage. Comparisons were made among treatment groups for 1) changes in the leaves, 2) population size of the birch casebearer at various times of the season, and 3) effects of damage-induced leaf changes on larval size. Damage-induced changes in the leaves were evident in nitrogen and phosphorus levels between 1991 and 1992, long-shoot length and number of buds, and bud development and leaf senescence. These changes were likely a result of nutrient depletion by insect feeding the previous year, reducing the tree's ability to compensate for losses. Population size of the birch casebearer between treatment groups changed very little throughout 1991 and 1992 suggesting that moths did not move far from the site of pupation. Positive correlation between nitrogen levels and egg density suggested that female moths might be able to distinguish between high and low leaf nitrogen levels, though this could occur within the same tree. Since headcapsule widths of Instar II larvae did not differ significantly between treatment groups, it appeared that damage-induced changes of white birch had no measurable effect on larval size. -- Leaf developmental changes, measured as water potential, water content, and fresh and dry leaf weights, were compared with seasonal changes in plant and insect life history stages. Egg hatch coincided with second leaf flush. Since eggs were laid on old leaves, it was suggested that Instar I larvae took advantage of nutrients being mobilized out of the older leaves and moving into younger leaves. -- The study showed no evidence for damage-induced leaf changes affecting success of the birch casebearer. However, there was speculation that the unusual life history pattern of the birch casebearer was adapted so that Instar I and II larvae could take advantage of mobilized leaf nutrients, lower water contents, and water potentials late in the season. Instar III and IV larvae, with faster growth, could take advantage of high leaf nutrients early in the season

Information Literacy in undergraduate research: transforming an old idea into a new environment.

Elizabeth Braaksma, Vera Armann-Keown, and Michele Piercey-Normore. Undergraduate research has historically been an integral component of the educational experience in the Faculty of Science at the University of Manitoba, but rapidly changing science-related disciplines pose unique challenges to identify, evaluate, acquire, and use information. Students are required to demonstrate competency in research papers and conduct laboratory research. Information is scrutinized by anonymous reviewers and is exposed to ethical and legal ramifications. A model was developed to implement information literacy (IL) into existing programs that already have a strong research foundation using the ACRL (Association of College and Research Libraries) standards for Science and Engineering. The model aligns both sets of learning outcomes (information literacy and discipline-specific), and provides sample exercises with rubrics for evaluation. The integration of IL learning outcomes within the context of a discipline in which the student has an interest, enables a more powerful learning environment than if the outcomes were separated. The program ensures the five IL competency standards are met at each level of a four-year degree, and that students take responsibility for their own success resulting in greater retention throughout their programs and into their future careers. The implications are that the IL integration will provide the tools necessary to help students remain within and successfully complete their academic programs; and gain added value to their knowledge and skills that can be extended into society or to a graduate degree and beyond

Comparison of lichen-forming cyanobacterial and green algal photobionts with free-living algae

Cyanobacteria of the genus Nostoc and green algae in the Chlorophyceae are widespread in nature and may occur in symbiotic associations with lichen-forming ascomycetes or as free-living cyanobacteria. Recent findings for some groups of lichens suggest that special lichen-forming photobiont lineages may exist independent of the free-living lineages, but few comparisons on photobiont growth, pigment, and polysaccharide production have been made. The goal of this study was to isolate photobionts, confirm their identity, and characterize their growth, pigment and polysaccharide production relative to free-living lineages. Algal growth, pigment contents, and polysaccharide concentration was measured using standard methods. The identification of Nostoc species was determined using transfer RNA for Leucine (trnL) nucleotide sequences and green algae using the internal transcribed spacer 1 of ribosomal DNA (ITS rDNA) sequences. An additional heptanucleotide repeat was present in the trnL gene of the Nostoc strain that associates with Leptogium rivulare. The biomass of pigment and polysaccharide production was highest in the lichenized Diplosphaera chodatii but the specific growth rate was highest in the free-living green alga, Chlorella vulgaris. The specific growth of the free-living Nostoc was higher than the lichenized Nostoc but pigment production was similar and polysaccharide production was lower than some of the lichenized Nostoc isolates. It was further hypothesized that the rates of growth, polysaccharide and pigment production may be key factors in compatibility of lichen algae with the fungus.</p

Transcriptome Comparison of Secondary Metabolite Biosynthesis Genes Expressed in Cultured and Lichenized Conditions of Cladonia rangiferina

Lichen secondary metabolites are natural products of high medicinal and industrial value, which are produced by the fungal symbiont (mycobiont) of lichens in response to environmental changes. It has been shown that the cultured mycobiont is capable of secondary metabolite production, specifically polyketides, and polyketide production is affected by the presence or absence of the algal or cyanobacterial symbiont (photobiont). Identification of polyketide synthases encoding genes is, in turn, key for understanding the regulation of secondary metabolite synthesis. Using a previously established method of resynthesis for Cladonia rangiferina as well as the sequenced and assembled genome of that species, we compared transcriptomes of C. rangiferina cultured alone and resynthesized with the photobiont (Asterochloris glomerata) to reveal transcriptionally active genes in secondary metabolic gene clusters, as well some of the neighbouring genes, induced by the presence of the photobiont and events of lichenization. The results identify potential candidates for PKS genes in C. rangiferina, identify potential neighbouring genes in the PKS cluster, and offer insights into further research. The study provides preliminary insights into the activity of several identified biosynthetic gene clusters (BGC) as well as interactions of genes within those clusters

Relationship between lichen species composition, secondary metabolites and soil pH, organic matter, and grain characteristics in Manitoba.

Many lichen secondary metabolites have functions related to the environmental conditions of lichen habitats but few studies have compared soil characteristics with lichen species composition or their secondary products. The goal of this study was to investigate the relationship between soil characteristics with lichen species composition and secondary metabolites. Five locations were chosen in Manitoba, each with five sites (transect), and each transect with five quadrats (1 m x 1 m). All species were collected from each of the quadrats, presence of secondary metabolites was determined by thin layer chromatography, and soil characteristics were examined. The results revealed that round sand grains were significantly higher in southeast Manitoba than other locations corresponding with a distinct species composition. Angular grains were significantly higher in northern locations, corresponding to a different group of species. Some of the significant relationships between soil characteristics and secondary metabolites include correlations of atranorin with pH, organic matter and sand content; fumarprotocetraric acid with organic matter and sand content; and usnic acid with pH and organic matter. A better understanding of the role of lichens with respect to soil characteristics will be important for improving soil stabilization in land reclamation.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

REGENERATION RESPONSES DIFFER AMONG THREE BOREAL MOSSES AFTER EXPOSURE TO EXTREME TEMPERATURES

Many factors may affect survival and establishment of moss vegetative propagules after dispersal, but little is known about the species-specific nature of the response. This study examined the survival and regeneration of gametophore fragments after exposure to temperature changes for three boreal forest mosses from different habitats: Dicranum polysetum, Orthotrichum obtusifolium, and Pleurozium schreberi. Fragments were cultured on water agar and survival and regeneration responses were recorded. Logistic regression analyses and AIC modeling evaluated the association between the response with the size of the gametophore fragments exposed to five abrupt or gradual temperatures for up to six time periods of exposure. The increased survival and regeneration was best explained when species were exposed to gradual rather than abrupt temperatures, lower than higher temperatures, and when the fragments had larger rather than smaller sizes. The mosses had different survival and regeneration responses that may be species-specific including clonal growth via the production of gametophore branches and protonemata, or mostly protonemata even when exposed to elevated temperatures.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author