some phytotoxic effects of fenitrothion on the germination and early seedling growth of picea glauca (moench) voss and betula alleghaniensis britton. 1979486750
carrier herbal medicine: traditional and contemporary plant use.the carrier, an athapaskan-speaking people of northcentral british columbia, occupy the sub-boreal spruce forests of the central interior. this report, which is based on field study, documents some traditional and contemporary knowledge of the medicinal use of plants by the carrier people. important medicinal plants include: abies lasiocarpa, alnus incana, arctostaphylos uva-ursi, artemisia frigida, fragaria virginiana, juniperus communis, picea glauca, pinus contorta, populus tremuloides, rubus ...19968735452
carrier herbal medicine: an evaluation of the antimicrobial and anticancer activity in some frequently used remedies.the antimicrobial properties of some traditional carrier herbal preparations were evaluated using an agar dilution method. pitch preparations were screened against known human pathogens: escherichia coli, staphylococcus aureus, pseudomonas aeruginosa, candida albicans and aspergillus fumigatus. the results indicated definite antimicrobial activity in the pitch preparations of picea glauca and pinus contorta and provide a starting point for pharmacognostic evaluation of these species. in addition ...19968771456
two highly divergent 5s rdna unit size classes occur in composite tandem array in european larch (larix decidua mill.) and japanese larch (larix kaempferi (lamb.) carr.).the 5s ribosomal dna unit structure and organization have been investigated in larix decidua and larix kaempferi using selective amplification of gene and spacer, sequence analysis and homologous probe hybridization. two highly divergent unit size classes of approximately 650 and 870 bp were detected in both species. sequence analysis in larix decidua revealed that length variations occur in the middle spacer region and are the result of duplications (in the long spacers) and considerable sequen ...199910584306
tetranorditerpene lactones, potent antifungal antibiotics for human pathogenic yeasts, from a unique species of oidiodendron.the culture filtrate of a fungus isolated from decaying picea glauca wood and tentatively identified as oidiodendron cf. truncatum showed strong antibiotic activity against the pathogenic yeast, candida albicans. four new tetranorditerpenoids, oidiodendrolides a (3), b (4), and c (5) and oidiodendronic acid (7) were isolated along with three known tetranorditerpenoids, ll-z1271 alpha (= pr1387) (1), pr1388 (2), and acrostalidic acid (6), from rice fermented by the above fungus. the structures of ...199910605057
changes in volatile terpene and diterpene resin acid composition of resistant and susceptible white spruce leaders exposed to simulated white pine weevil damage.induced (traumatic) resin in white spruce (picea glauca (moench) voss) leaders resistant or susceptible to the white pine weevil (pissodes strobi peck) was analyzed for volatile terpenes and diterpene resin acids after simulated white pine weevil damage. leaders from 331 trees were wounded just below the apical bud with a 1-mm diameter drill, coinciding with the natural time of weevil oviposition in the spring. leaders were removed in the fall, and the bark and xylem from the upper and lower reg ...200011269960
photosynthesis and carbon allocation of six boreal tree species grown in understory and open seedlings of abies balsamea (l.) mill, picea glauca (moench) voss, pinus contorta loudon, betula papyrifera marsh., populus tremuloides michx. and populus balsamifera l. were transplanted in the spring, in pots, to the understory of a mixed p. tremuloides-p. balsamifera stand or to an adjacent open site. growth and leaf characteristics were measured and photosynthetic light response curves determined in mid-august. overall, the coniferous seedlings showed less photosynthetic plastic ...200111276418
the effect of salinity on the emergence and seedling growth of picea mariana, picea glauca, and pinus banksiana.mining operations in areas of the boreal forest have caused salinity issues to be a major concern for reclamation. one of the factors determining successful reclamation is the ability of species to self-propagate. the effects of salinity on the seedling emergence and early growth of three boreal forest conifers: picea mariana, picea glauca, and pinus banksiana were determined. seeds were planted in sand moistened with solutions of various concentrations of sodium chloride or sodium sulfate. seed ...200111586777
an improved procedure for production of white spruce (picea glauca) transgenic plants using agrobacterium efficient and reproducible procedure for the transformation of white spruce (picea glauca [moench] voss) embryogenic tissues was developed using a. tumefaciens-mediated gene transfer. rapidly dividing white spruce embryogenic tissues were co-cultivated with disarmed a. tumefaciens strains containing additional copies of the virulence regions from plasmid ptok47. the plasmid pbi121, containing the neomycin phosphotransferase ii (nptii) gene providing kanamycin resistance as a selectable marker ...200111604447
effects of soil temperature on parameters of a coupled photosynthesis-stomatal conductance examine the effects of soil temperature on a coupled photosynthesis-stomatal conductance model, seedlings of trembling aspen (populus tremuloides michx.), jack pine (pinus banksiana lamb.), black spruce (picea mariana (mill.) b.s.p.) and white spruce (picea glauca (moench) voss) were exposed to soil temperatures ranging from 5 to 35 degrees c for 4 months. light and co(2) response curves of foliar gas exchange were measured for model parameterization. the effects of soil temperature on four k ...200212184971
a desaturase-like protein from white spruce is a delta(9) desaturase.gymnospermae seed lipids are characterized by a high degree of desaturation, most having a delta(9) double bond. by degenerate polymerase chain reaction (pcr) we have isolated a white spruce (picea glauca) cdna clone that encodes an amino acid sequence sharing a high degree of homology with other putative plant acyl-coenzyme a (coa) des9 desaturases. both in vivo and in vitro expression studies in a delta(9) desaturase-deficient yeast strain demonstrated the desaturation functionality of the whi ...200212208502
the effects of polyethylene glycol on gene expression of developing white spruce somatic embryos.somatic embryogenic cultures of white spruce (picea glauca) represent a valuable system to study molecular mechanisms regulating embryo development because many embryos of defined developmental stages can be generated. the inclusion of polyethylene glycol (peg) in the maturation medium can improve the number and quality of embryos produced. to learn more about the mechanism of action of peg, we analyzed transcript profiles of stage-specific embryos matured without (control) or with (peg treated) ...200312529514
effects of exogenous gibberellin and auxin on shoot elongation and vegetative bud development in seedlings of pinus sylvestris and picea glauca.the hormonal control of stem unit (foliar appendage and axillary structure, if present, plus subtending internode) number and length was investigated in shoots of scots pine (pinus sylvestris l.) and white spruce (picea glauca (moench) voss). seedlings were treated with six gibberellins (ga1, ga3, ga4, ga5, ga9 and ga20) and two auxins (indole-3-acetic acid (iaa) and naphthaleneacetic acid (naa)) when either neoformed growth was occurring or the terminal vegetative bud was developing. hormones w ...200312533302
mycorrhizal and root endophytic fungi of containerized picea glauca seedlings assessed by rdna sequence analysis.fungi colonizing fine roots of containerized picea glauca seedlings were assessed in four large conifer nurseries in northern alberta. pcr amplification of fungal rdna (internal transcribed spacer and a portion of the 5' end of the large subunit gene) from random samples of fine feeder roots gave between 1 and 4 amplicons per seedling. amplicons were either separated by electrophoresis and sequenced directly, or cloned and sequenced. the resulting sequences were compared to sequences obtained fr ...200312545311
reduction in turgid water volume in jack pine, white spruce and black spruce in response to drought and paclobutrazol.significant reductions in needle water content were observed in white spruce (picea glauca (moench) voss), black spruce (picea mariana (mill) b.s.p.), and jack pine (pinus banksiana lamb.) seedlings in response to a 10-day drought, although turgor was apparently maintained. when the seedlings were re-watered after the drought, jack pine needles regained their original saturated volume, whereas white spruce and black spruce needles did not. significant drought-induced reductions in turgor-loss vo ...200012651520
freezing tolerance of conifer seeds and germinants.survival after freezing was measured for seeds and germinants of four seedlots each of interior spruce (picea glauca x engelmannii complex), lodgepole pine (pinus contorta dougl. ex loud.), douglas-fir (pseudotsuga menziesii (mirb.) franco) and western red cedar (thuja plicata donn ex d. donn). effects of eight seed treatments on post-freezing survival of seeds and germinants were tested: dry, imbibed and stratified seed, and seed placed in a growth chamber for 2, 5, 10, 15, 20 or 30 days in a 1 ...200314652223
seasonal photosynthetic responses to light and temperature in white spruce (picea glauca) seedlings planted under an aspen (populus tremuloides) canopy and in the open.photosynthetic light and temperature response curves were measured seasonally in seedlings of white spruce (picea glauca (moench.) voss) grown for two years in the understory of aspen (populus tremuloides michx.) or in the open in central alberta. light-saturated rate of net photosynthesis, the optimum temperature for net photosynthesis, transpiration rate, photochemical efficiency, and stomatal and mesophyll conductances increased from spring to summer and declined thereafter, whereas dark resp ...199714759835
pollen management for intensive seed orchard production.artificially increasing pollen supply (supplemental mass pollination (smp)) to conifer seed orchards has the potential to increase seed yields and improve the genetic worth of seed crops that would otherwise suffer from the detrimental effects of pollen contamination and unbalanced paternal contribution. however, success rates, measured as the proportion of seed fertilized by smp, have been low. this review examines the concepts underlying smp and presents data for two smp field trials with doug ...199514965935
seasonal nutrient dynamics in white pine and white spruce in response to environmental manipulation.seasonal retranslocation in white pine (pinus strobus l.) and white spruce (picea glauca (moench) voss) was examined in response to silvicultural treatments (scarification, annual fertilization application, and annual control of competing vegetation with herbicide) that changed both environmental conditions and the growth rate of the trees. four years after plantation establishment and initial treatment, nutrient accumulation in current-year needles of white pine and retranslocation from 1-year- ...199514965969
the effect of reduced glutathione on morphology and gene expression of white spruce (picea glauca) somatic embryos.inclusions of reduced glutathione (gsh) in the maturation medium increased the conversion frequency of white spruce somatic embryos without the need of a partial drying treatment (pdt). this beneficial effect was the result of major alterations in morphology and gene expression during the maturation period. compared with control embryos, gsh-treated embryos showed a differential accumulation of storage products, i.e. preferential deposition of starch, the reduced formation of protein bodies, and ...200414966213
effect of photon flux density on carbon assimilation and chlorophyll a fluorescence of cold-stored white spruce and lodgepole pine seedlings.white spruce (picea glauca (moench.) voss) and lodgepole pine (pinus contorta dougl. var. latifolia engelm.) seedlings previously held in dark, frozen storage (-2 degrees c) for 2.5 or 6 months, and nursery-grown white spruce seedlings lifted in summer were exposed to photon flux densities (pfds) similar to those that might be encountered at planting. photosynthetic gas exchange and chlorophyll a (chl a) fluorescence were examined in cold-stored and summer-lifted seedlings before and after a 9 h ...199314969928
planting stress in newly planted jack pine and white spruce. 1. factors influencing water uptake.bareroot jack pine (pinus banksiana lamb.) seedlings (2 + 0) and bareroot white spruce (picea glauca (moench) voss) transplants (1 1/2 + 1 1/2) were taken from cold storage and planted on a clearcut forest site in northeastern ontario on several dates between may 6 and june 5 during which period soil temperature at 15 cm depth increased from 0 to 18 degrees c. additional cold-stored trees were transferred to a greenhouse where they were grown in pots for 0, 7 or 28 days and then placed with thei ...198814972837
planting stress in newly planted jack pine and white spruce. 2. changes in tissue water potential components.water relations of bare-root jack pine (pinus banksiana lamb.) and white spruce (picea glauca (moench) voss) planted in a greenhouse and on a boreal cut-over site were examined during the first growing season. in field-planted trees, maximum stomatal conductances (g(wv)) were initially low (< 0.10 cm s(-1)). base and minimum xylem pressure potentials (psi(x(base)) and psi(x(min))) were less than -1.5 and -1.7 mpa for jack pine and -2.0 and -2.6 mpa for white spruce, respectively. during the grow ...198814972838
acquired thermotolerance of jack pine, white spruce and black spruce seedlings.the acquired thermotolerance of first-year seedlings of jack pine (pinus banksiana lamb.) hardened at 36, 38, 40 or 42 degrees c for 90, 180 or 360 minutes and of black spruce (picea mariana (mill.) b.s.p.) hardened at 34, 36, 38 or 40 degrees c for 30, 90, 180 or 360 minutes was determined by comparison of needle damage to that of non-hardened seedlings (25 degrees c) following exposure to temperatures of 49 and 47.5 degrees c, respectively. compared to seedlings kept at 25 degrees c, heat inju ...199114972899
accumulation of free amino acids in the shoots and roots of three northern conifers during drought.the effects of drought on the free amino acid pools in 21- to 23-week-old seedlings of black spruce (picea mariana (mill.) britt.), white spruce (picea glauca (moench.) voss) and jack pine (pinus banksiana lamb.) were followed during soil drying. although water and pressure potentials were sensitive to water deficits, large changes in osmotic potential were not recorded until after the development of severe drought. total soluble amino nitrogen in the shoots and roots of the three species rose a ...199014972940
effects of carbon dioxide enrichment and nitrogen supply on growth of boreal tree seedlings.the effects of two levels of atmospheric carbon dioxide (350 microl l(-1), 750 microl l(-1)) and three levels of nitrogen (15.5 mm, 1.55 mm, 0.155 mm n) on biomass accumulation and partitioning were examined in aspen (populus tremuloides michx.) and white spruce (picea glauca (moench) voss) seedlings grown in controlled environment rooms for 100 days after germination. nitrogen supply had pronounced effects on biomass accumulation, height, and leaf area of both species. root weight ratio (rwr) o ...198614975856
relationships among drought resistance, transpiration rates, and abscisic acid levels in three northern conifers.water potentials, transpiration rates and abscisic acid (aba) levels in shoots of black spruce (picea mariana (mill.) bsp), white spruce (picea glauca (moench) voss) and jack pine (pinus banksiana lamb.) seedlings were monitored during periods of drought and recovery from drought. abscisic acid contents of shoots increased during the period of drought as water potentials decreased. the increase in levels of aba was closely associated with a decrease in rates of transpiration. in the spruces, the ...198614975892
germination, growth and gas exchange of selected boreal forest seedlings in soil containing oil sands tailings.greenhouse experiments were conducted to determine the effects of soil enriched in fine tailings (ft), produced by the oil sands extraction, on germination, seedling growth and physiology of several plant species of the boreal forest. the germination of seeds was initially delayed by 15% ft in dogwood (cornus stolonifera michx) and jack pine (pinus banksiana lamb) but not in white spruce [picea glauca (moench) voss]. in the second set of experiments we showed that all dogwood seedlings survived ...200015092982
element accumulation patterns of deciduous and evergreen tree seedlings on acid soils: implications for sensitivity to manganese toxicity.foliar nutrient imbalances, including the hyperaccumulation of manganese (mn), are correlated with symptoms of declining health in sensitive tree species growing on acidic forest soils. the objectives of this study were to: (1) compare foliar nutrient accumulation patterns of six deciduous (sugar maple (acer saccharum marsh.), red maple (acer rubrum l.), red oak (quercus rubra l.), white oak (quercus alba l.), black cherry (prunus serotina ehrh.) and white ash (fraxinus americana l.)) and three ...200515519989
interacting influence of light and size on aboveground biomass distribution in sub-boreal conifer saplings with contrasting shade tolerance.plant size often influences shade tolerance but relatively few studies have considered the functional response of taller plants to contrasting light environments. several boreal and sub-boreal abies, picea and pinus species were studied along a light (0-90% full sunlight) and size (30-400-cm high) gradient to examine the interactive influence of tree size and light availability on aboveground biomass distribution. sampling was conducted in two regions of canada: (a) british columbia, for abies l ...200515631985
prolonged herbicide-induced vegetation changes in a regenerating boreal aspen clearcut.a soil-active herbicide (hexazinone) was applied (0, 2, and 4 kg/ha of active ingredient) in a 3-year-old regenerating boreal populus tremuloides michx. (aspen) clearcut to determine its effect on the compositional and structural development of the vegetation. woody stem densities and plant foliar cover were evaluated prior to and 2, 6, and 17 years after treatment. herbicide treatment at the 2 and 4 kg/ha rates reduced tree and total woody stem densities relative to the 0 kg/ha level. the 4 kg/ ...200516102889
extraction of condensed tannins from cervid feed and feces and quantification using a radial diffusion assay.a radial diffusion assay was employed to quantify condensed tannins (ct) in feed and feces of mule deer (odocoileus hemionus) and white-tailed deer (o. virginianus). this biological assay measures the precipitation of bovine serum albumin (bsa), with the area of the precipitation ring being proportional to the amount of extracted ct applied to the well. ct extracted from the bark of white spruce (picea glauca) was used as the standard. ct were extracted with 70% (v/v) aqueous acetone and precipi ...200516365703
foliage influences forced convection heat transfer in conifer branches and buds.conifer foliage structures affect branch and bud temperature by altering the development and convective resistance of the thermal boundary layer. this paper examines foliage effects on forced convection in branches and buds of picea glauca (moench) voss and pinus contorta dougl. ex. loud., two species that represent the range of variation in foliage structure among conifers. forced convection is characterized by a power law relating nusselt (heat transfer) and reynolds (boundary layer developmen ...200616539606
relationships between stand composition and ectomycorrhizal community structure in boreal mixed-wood forests.we investigated the community structure of ectomycorrhizal fungi under varying overstory tree compositions in the southern mixed-wood boreal forest of quebec. sampling took place at two locations of differing postfire ages and nine 100-m2 plots were sampled per location. the dominant overstory tree species in the plots were trembling aspen (populus tremuloides michx.), white birch (betula papyrifera marsh.) or white spruce [picea glauca (moench) voss], and balsam fir [abies balsamea (l.) mill.]. ...200616699911
ectomycorrhizal fungi affect the physiological responses of picea glauca and pinus banksiana seedlings exposed to an nacl gradient.we tested the effects of ectomycorrhizal (ecm) inoculation on greenhouse-grown white spruce (picea glauca (moench) voss) and jack pine (pinus banksiana l.) seedlings to be used for revegetation of salt-affected tailing sands resulting from the exploitation of oil sand in northeastern alberta, canada. white spruce and jack pine seedlings were inoculated with three ecm fungi selected for their in vitro tolerance to excess na+ and cl-: hebeloma crustuliniforme (bull) quel. uamh 5247, laccaria bicol ...200616740494
gas exchange and growth responses of ectomycorrhizal picea mariana, picea glauca, and pinus banksiana seedlings to nacl and spruce (picea mariana), white spruce (picea glauca), and jack pine (pinus banksiana) seedlings were inoculated with hebeloma crustuliniforme or laccaria bicolor and subjected to nacl and na (2)so (4) treatments. the effects of ectomycorrhizas on salt uptake, growth, gas exchange, and needle necrosis varied depending on the tree and fungal species. in jack pine seedlings, ectomycorrhizal (ecm) fungi reduced shoot and root dry weights and in the ecm white spruce, there was a small increase i ...200616755463
impacts of forest fragmentation on the mating system and genetic diversity of white spruce (picea glauca) at the landscape level.we studied the mating system of white spruce (picea glauca) in a landscape fragmented by agriculture in northern ontario, canada. we sampled 23 stands that ranged in size from 1 to >500 trees isolated by 250-3000 m from the nearest other stand. six polymorphic allozyme loci from four enzyme systems were used to genotype approximately 10 000 embryos from 104 families. we detected no allele frequency heterogeneity in the pollen pool among stands or families (phi(ft)=-0.025). overall, estimates of ...200616912700
forest dynamics after successive spruce budworm outbreaks in mixedwood order to assess the long-term spatiotemporal influence of the spruce budworm in sub-boreal mixedwood forests, we studied the effect of three successive outbreaks in a region of western quebec, canada. we used dendrochronology to detect past outbreaks in three areas (111-185 ha), based on the recruitment age of balsam fir (abies balsamea) and on growth patterns of white spruce (picea glauca), the two main host species of this defoliating insect. we also used a series of aerial photographs take ...200616995632
adventitious root production and plastic resource allocation to biomass determine burial tolerance in woody plants from central canadian coastal dunes.burial is a recurrent stress imposed upon plants of coastal dunes. woody plants are buried on open coastal dunes and in forested areas behind active blowouts; however, little is known about the burial responses and adaptive traits of these species. the objectives of this study were: (a) to determine the growth and morphological responses to burial in sand of seven woody plant species native to central canadian coastal dunes; and (b) to identify traits that determine burial tolerance in these spe ...200617018567
comparative genome mapping among picea glauca, p. mariana x p. rubens and p. abies, and correspondence with other pinaceae.a composite linkage map was constructed from four individual maps for the conifer picea glauca (moench) voss, from anonymous and gene-specific markfers (714 aflps, 38 ssrs, and 53 estps). a total of 12 linkage groups were delineated with an average marker density of 2.7 cm. macro-synteny and macro-colinearity comparisons with two other composite linkage maps developed for the species complex p. mariana (mill.) b.s.p. x p. rubens sarg., and for p. abies (l.) karst. revealed an identical number of ...200617061103
diversity of the small subunit ribosomal rna gene of the arbuscular mycorrhizal fungi colonizing clintonia borealis from a mixed-wood boreal forest.arbuscular mycorrhizal fungi (amf) communities in clintonia borealis roots from a boreal mixed forests in northwestern québec were investigated. roots were sampled from 100 m2 plots whose overstory was dominated by either trembling aspen (populus tremuloides michx.), white birch (betula papyrifera marsh.), or mixed white spruce (picea glauca (moench) voss) and balsam fir (abies balsamea (l.) mill.). part of the 18s ribosomal gene of the amf was amplified and the resulting pcr products were clone ...200617064264
aminocyclopropane carboxylic acid synthase is a regulated step in ethylene-dependent induced conifer defense. full-length cdna cloning of a multigene family, differential constitutive, and wound- and insect-induced expression, and cellular and subcellular localization in spruce and douglas conifer stems, formation of chemical defenses against insects or pathogens involves specialized anatomical structures of the phloem and xylem. oleoresin terpenoids are formed in resin duct epithelial cells and phenolics accumulate in polyphenolic parenchyma cells. ethylene signaling has been implicated in the induction of these chemical defenses. recently, we reported the cloning of 1-aminocyclopropane-1-carboxylic acid oxidase (aco) from spruce (picea spp.) and douglas fir (pseudotsuga menzi ...200717122070
interactions among white spruce tannins, bacillus thuringiensis subsp. kurstaki, and spruce budworm (lepidoptera: tortricidae), on larval survival, growth, and development.the interactions among white spruce, picea glauca (moench) voss, purified acetone tannin extracts (hydrolyzable and condensed tannin), bacillus thuringiensis subsp. kurstaki cry1a(c) delta-endotoxin strain hd-73 (btk), and spruce budworm, choristoneura fumiferana (clemens) (lepidoptera: tortricidae) on larval survival, growth, and development were investigated over the whole larval feeding period by using artificial diet supplemented with three concentrations of btk toxins per milliliter of diet ...200617195671
purification, characterization, and molecular gene cloning of an antifungal protein from ginkgo biloba seeds.a novel basic protein with antifungal activity was isolated from the seeds of ginkgo biloba and purified to homogeneity. the protein inhibited the growth of some fungi (fusarium oxysporum, trichoderma reesei, and candida albicans) but did not exhibit antibacterial action against escherichia coli. furthermore, this protein showed weak inhibitory activity against the aspartic protease pepsin. to design primers for gene amplification, the nh(2)-terminal and partial internal amino acid sequences wer ...200717338634
conifer r2r3-myb transcription factors: sequence analyses and gene expression in wood-forming tissues of white spruce (picea glauca).several members of the r2r3-myb family of transcription factors act as regulators of lignin and phenylpropanoid metabolism during wood formation in angiosperm and gymnosperm plants. the angiosperm arabidopsis has over one hundred r2r3-mybs genes; however, only a few members of this family have been discovered in gymnosperms.200717397551
alteration of soil rhizosphere communities following genetic transformation of white spruce.the application of plant genetic manipulations to agriculture and forestry with the aim of alleviating insect damage through bacillus thuringiensis transformation could lead to a significant reduction in the release of pesticides into the environment. however, many groups have come forward with very valid and important questions related to potentially adverse effects, and it is crucial to assess and better understand the impact that this technology might have on ecosystems. in this study, we ana ...200717468272
controls of growth phenology vary in seedlings of three, co-occurring ecologically distinct northern conifers.the objective of this study was to investigate the effects of temperature and seed-source elevation on height-growth phenology of three co-occurring and ecologically distinct northern conifers (pinus contorta dougl. ex loud. var. latifolia (lodgepole pine), picea glauca (moench) voss x picea engelmannii parry ex engelm. (interior spruce) and abies lasiocarpa (hook.) nutt. (subalpine fir)). seed from populations of the three indigenous and co-occurring species was collected across an elevational ...200717472945
phylogeography of spruce beetles (dendroctonus rufipennis kirby) (curculionidae: scolytinae) in north america.tree-feeding insects that are widespread in north temperate regions are excellent models for studying how past glaciations have impacted differentiation and speciation. we used mitochondrial dna (mtdna) sequences and allele frequencies at nine microsatellite loci to examine genetic population structure across the current range of the spruce beetle (dendroctonus rufipennis), an economically important insect in north america. two major haplotype groups occur across northern north america, from new ...200717561913
testing of a heterologous, wound- and insect-inducible promoter for functional genomics studies in conifer defense.large-scale sequencing of conifer cdnas and targeted molecular cloning have identified many putative conifer defense genes. expression of many of these genes is induced in response to biotic stress and some may be expressed only in a few specialized tissues or cells. proven functional genomics approaches to test these genes involve expression of proteins in escherichia coli or yeast for biochemical characterization or constitutive over-expression in transformed plants. plant transformation to te ...200717671786
the co-occurrence of ectomycorrhizal, arbuscular mycorrhizal, and dark septate fungi in seedlings of four members of the pinaceae.although roots of species in the pinaceae are usually colonized by ectomycorrhizal (em) fungi, there are increasing reports of the presence of arbuscular mycorrhizal (am) and dark septate endophytic (dse) fungi in these species. the objective of this study was to determine the colonization patterns in seedlings of three pinus (pine) species (pinus banksiana, pinus strobus, pinus contorta) and picea glauca x picea engelmannii (hybrid spruce) grown in soil collected from a disturbed forest site. s ...200818157555
biotic disturbance in expanding subarctic forests along the eastern coast of hudson bay.* the past and present occurrence of insect disturbance on white spruce (picea glauca) trees was evaluated at their northern range limit on the eastern coast of hudson bay, and its effects on tree growth and population dynamics studied. * three sites were sampled along an altitudinal gradient. ring-width chronologies and stem analysis were used to evaluate tree growth. the occurrence of holes in the bark, of resin pockets and blue-stain fungi, and ring-width evidence for growth releases were use ...200818346107
spread and persistence of a rugulosin-producing endophyte in picea glauca seedlings.we have studied picea glauca (white spruce) endophyte colonization and its affect on the growth of choristoneura fumiferana (spruce budworm). here we examine the spread and persistence of a rugulosin-producing endophyte and rugulosin in needles from trees maintained in the nursery, as well as in trees planted in a test field site. additionally, we report toxicity of rugulosin against three p. glauca needle herbivores: c. fumiferana, lambdina fiscellaria (hemlock looper) and zeiraphera canadensis ...200818487038
population genomics: a new generation of genome scans to bridge the gap with functional genomics.population genomics is an increasingly popular approach to investigate the genetic basis of adaptation and speciation at the genome scale. however, it has so far largely failed to go beyond the mere identification of anonymous markers displaying selection signatures. will population genomics ever be up to our expectations and able to really pinpoint genes underlying adaptation and speciation processes? in this issue of molecular ecology, namroud et al. use population genomics to investigate loca ...200818662224
scanning the genome for gene single nucleotide polymorphisms involved in adaptive population differentiation in white spruce.conifers are characterized by a large genome size and a rapid decay of linkage disequilibrium, most often within gene limits. genome scans based on noncoding markers are less likely to detect molecular adaptation linked to genes in these species. in this study, we assessed the effectiveness of a genome-wide single nucleotide polymorphism (snp) scan focused on expressed genes in detecting local adaptation in a conifer species. samples were collected from six natural populations of white spruce (p ...200818662225
patterns of divergence among conifer ests and polymorphism in pinus sylvestris identify putative selective sweeps.finding genes that are under positive selection is a difficult task, especially in non-model organisms. here, we have analyzed expressed sequence tag (est) data from 4 species (pinus pinaster, pinus taeda, picea glauca, and pseudotsuga menziesii) to investigate selection patterns during their evolution and to identify genes likely to be under positive selection. to confirm selection, population samples of these genes have been sequenced in pinus sylvestris, a species that was not included in the ...200818775901
involvement of pinus taeda myb1 and myb8 in phenylpropanoid metabolism and secondary cell wall biogenesis: a comparative in planta analysis.the involvement of two r2r3-myb genes from pinus taeda l., ptmyb1 and ptmyb8, in phenylpropanoid metabolism and secondary cell wall biogenesis was investigated in planta. these pine mybs were constitutively overexpressed (oe) in picea glauca (moench) voss, used as a heterologous conifer expression system. morphological, histological, chemical (lignin and soluble phenols), and transcriptional analyses, i.e. microarray and reverse transcription quantitative pcr (rt-qpcr) were used for extensive ph ...200818805909
genetic variability of canadian populations of the sapstain fungus ophiostoma piceae.abstract genetic diversity was studied in seven canadian populations of ophiostoma piceae, the most prevalent sapstain fungus in canadian softwoods. a total of 239 single-spore isolates were recovered following a systematic survey of sapstain fungi in logs and lumber at seven selected sawmills in six canadian provinces (british columbia, alberta, saskatchewan, ontario, québec, and new brunswick). sampling was carried out on five commercially important softwood species: balsam fir (abies balsamea ...200118943849
effects of nacl on responses of ectomycorrhizal black spruce (picea mariana), white spruce (picea glauca) and jack pine (pinus banksiana) to spruce (picea mariana), white spruce (picea glauca) and jack pine (pinus banksiana) were inoculated with suillus tomentosus and subjected to potassium fluoride (1 mm kf and 5 mm kf) in the presence and absence of 60 mm nacl. the nacl and kf treatments reduced total dry weights in jack pine and black spruce seedlings, but they did not affect total dry weights in white spruce seedlings. the addition of 60 mm nacl to kf treatment solutions alleviated fluoride-induced needle injury in ectomyco ...200919121099
mycorrhizal fungi supply nitrogen to host plants in arctic tundra and boreal forests: 15n is the key signal.symbiotic fungi's role in providing nitrogen to host plants is well-studied in tundra at toolik lake, alaska, but little-studied in the adjoining boreal forest ecosystem. along a 570 km north-south transect from the yukon river to the north slope of alaska, the 15n content was strongly reduced in ectomycorrhizal and ericoid mycorrhizal plants including betula, salix, picea mariana (p. mill.) b.s.p., picea glauca moench (voss), and ericaceous plants. compared with the 15n content of soil, the fol ...200919190704
sequence analysis and functional characterization of the promoter of the picea glauca cinnamyl alcohol dehydrogenase gene in transgenic white spruce plants.the enzyme cinnamyl alcohol dehydrogenase (cad) catalyses the last step of lignin monomer synthesis, and is considered as a molecular marker of cell wall lignification in different plants species. here, we report the isolation and analysis of 5' flanking genomic dna regions upstream to the cad gene, from two conifers, i.e. white spruce (picea glauca (moench) voss) and loblolly pine (pinus taeda l.). sequence comparisons with available cad gene promoters from angiosperms highlighted the conservat ...200919288108
sabath methyltransferases from white spruce (picea glauca): gene cloning, functional characterization and structural analysis.known members of the plant sabath family of methyltransferases have important biological functions by methylating hormones, signalling molecules and other metabolites. while all previously characterized sabath genes were isolated from angiosperms, in this article, we report on the isolation and functional characterization of sabath genes from white spruce (picea glauca [moench] voss), a gymnosperm. through est database search, three genes that encode proteins significantly homologous to known sa ...200919369216
take me to your leader: does early successional nonhost vegetation spatially inhibit pissodes strobi (coleoptera: curculionidae)?the spatial influences of host and nonhost trees and shrubs on the colonization patterns of white pine weevil pissodes strobi (peck) were studied within a stand of planted interior hybrid spruce [picea glauca (moench) voss x picea engelmannii (parry) ex engelm.]. planted spruce accounted for one third of all trees within the stand, whereas the remaining two thirds were comprised of early-successional nonhost vegetation, such as alder (alnus spp.), paper birch (betula papyrifera marsh.), black co ...200919689899
hydraulic acclimation to shading in boreal conifers of varying shade tolerance.the purpose of this study was to determine how shading affects the hydraulic and wood-anatomical characteristics of four boreal conifers (pinus banksiana, pinus contorta, picea glauca and picea mariana) that differ in shade tolerance. plants were grown in an open field and under a deciduous-dominated overstory for 6 years. sapwood- and leaf-area specific conductivity, vulnerability curves, and anatomical measurements (light and scanning electron microscopy) were made on leading shoots from six t ...201019968826
impact of endochitinase-transformed white spruce on soil fungal biomass and ectendomycorrhizal symbiosis.the impact of transgenic white spruce [picea glauca (moench) voss] containing the endochitinase gene (ech42) on soil fungal biomass and on the ectendomycorrhizal fungi wilcoxina spp. was tested using a greenhouse trial. the measured level of endochitinase in roots of transgenic white spruce was up to 10 times higher than that in roots of nontransformed white spruce. the level of endochitinase in root exudates of three of four ech42-transformed lines was significantly greater than that in control ...201020173071
forest restoration in a mixed-ownership landscape under climate change.the extent to which current landscapes deviate from the historical range of natural variability (rnv) is a common means of defining and ranking regional conservation targets. however, climate-induced shifts in forest composition may render obsolete restoration strategies and conservation targets based on historic climate conditions and disturbance regimes. we used a spatially explicit forest ecosystem model, landis-ii, to simulate the interaction of climate change and forest management in northe ...201020405791
subgroup 4 r2r3-mybs in conifer trees: gene family expansion and contribution to the isoprenoid- and flavonoid-oriented responses.transcription factors play a fundamental role in plants by orchestrating temporal and spatial gene expression in response to environmental stimuli. several r2r3-myb genes of the arabidopsis subgroup 4 (sg4) share a c-terminal ear motif signature recently linked to stress response in angiosperm plants. it is reported here that nearly all sg4 myb genes in the conifer trees picea glauca (white spruce) and pinus taeda (loblolly pine) form a monophyletic clade (sg4c) that expanded following the split ...201020732878
programmed cell death of the megagametophyte during post-germinative growth of white spruce (picea glauca) seeds is regulated by reactive oxygen species and the ubiquitin-mediated proteolytic system.the megagametophyte of white spruce (picea glauca) seeds undergoes programmed cell death following seed germination. this process is characterized by distinct morphological and biochemical features, such as dna fragmentation and the induction of proteases. biphasic production of hydrogen peroxide was detected in the megagametophyte following seed germination. ros scavengers or inhibitors of ros production decreased caspase-like protease activity and slowed the progression of cell death. one cata ...201020833629
an in silico analysis of the mitochondrial protein import apparatus of in silico analysis of the mitochondrial protein import apparatus from a variety of species; including chlamydomonas reinhardtii, chlorella variabilis, ectocarpus siliculosus, cyanidioschyzon merolae, physcomitrella patens, selaginella moellendorffii, picea glauca, oryza sativa and arabidopsis thaliana was undertaken to determine if components differed within and between plant and non-plant species.201021078193
climate sensitivity of gaseous elemental mercury dry deposition to plants: impacts of temperature, light intensity, and plant species.foliar accumulations of gaseous elemental mercury (gem) were measured in three plant species between nominal temperatures of 10 and 30 °c and nominal irradiances of 0, 80, and 170 w m(-2) (300 nm-700 nm) in a 19 m(3) controlled environment chamber. the plants exposed were as follows: white ash (fraxinus americana; wa); white spruce (picea glauca; ws); and kentucky bluegrass (poa partensis; kybg). foliar enrichments in the mercury stable isotope ((198)hg) were used to measure mercury accumulation ...201021142175
cree antidiabetic plant extracts display mechanism-based inactivation of cyp3a4.seventeen cree antidiabetic medicinal plants were studied to determine their potential to inhibit cytochrome p450 3a4 (cyp3a4) through mechanism-based inactivation (mbi). the ethanolic extracts of the medicinal plants were studied for their inhibition of cyp3a4 using the substrates testosterone and dibenzylfluorescein (dbf) in high pressure liquid chromatography (hplc) and microtiter fluorometric assays, respectively. using testosterone as a substrate, extracts of alnus incana, sarracenia purpur ...201121186373
host associations between fungal root endophytes and boreal trees.fungal root endophytes colonize root tissue concomitantly with mycorrhizal fungi, but their identities and host preferences are largely unknown. we cultured fungal endophytes from surface-sterilized cenococcum geophilum ectomycorrhizae of betula papyrifera, abies balsamea, and picea glauca from two boreal sites in eastern canada. isolates were initially grouped on the basis of cultural morphology and then identified by internal transcribed spacer ribosomal dna sequencing or by pcr restriction fr ...201121475991
assessing the potential for rhizoremediation of pcb contaminated soils in northern regions using native tree species.rhizosphere bioremediation of polychlorinated biphenyls (pcbs) offers a potentially inexpensive approach to remediating contaminated soils that is particularly attractive in remote regions including the arctic. we assessed the abilities of two tree species native to alaska, salix alaxensis (felt-leaf willow) and picea glauca (white spruce), to promote microbial biodegradation of pcbs via the release of phytochemicals upon fine root death. crushed fine roots, biphenyl (pcb analogue) or salicylate ...201121596420
site factors and management influence short-term host resistance to spruce budworm, choristoneura fumiferana (clem.), in a species-specific manner.background: this study examined the interactions between thinning and soil drainage classes on the resistance of balsam fir, abies balsamea (l.) mill, white spruce, picea glauca (moench) voss, and black spruce, p. mariana (mill.) bsp, to spruce budworm, choristoneura fumiferana (clem.), defoliation 1 year after treatment. to estimate host tree resistance, foliage production and larval foliage consumption were determined to generate an index of resistance quantifying the amount of residual foliag ...201121796758
the heterogeneous levels of linkage disequilibrium in white spruce genes and comparative analysis with other plants, knowledge about linkage disequilibrium (ld) is relevant for the design of efficient single-nucleotide polymorphism arrays in relation to their use in population and association genomics studies. previous studies of conifer genes have shown ld to decay rapidly within gene limits, but exceptions have been reported. to evaluate the extent of heterogeneity of ld among conifer genes and its potential causes, we examined ld in 105 genes of white spruce (picea glauca) by sequencing a panel o ...201121897435
Biosynthesis of the major tetrahydroxystilbenes in spruce, astringin and isorhapontin, proceeds via resveratrol and is enhanced by fungal infection.Stilbenes are dibenzyl polyphenolic compounds produced in several unrelated plant families that appear to protect against various biotic and abiotic stresses. Stilbene biosynthesis has been well described in economically important plants, such as grape (Vitis vinifera), peanut (Arachis hypogaea), and pine (Pinus species). However, very little is known about the biosynthesis and ecological role of stilbenes in spruce (Picea), an important gymnosperm tree genus in temperate and boreal forests. To ...201121865488
the expression pattern of the picea glauca defensin 1 promoter is maintained in arabidopsis thaliana, indicating the conservation of signalling pathways between angiosperms and gymnosperms.a 1149 bp genomic fragment corresponding to the 5' non-coding region of the pgd1 (picea glauca defensin 1) gene was cloned, characterized, and compared with all arabidopsis thaliana defensin promoters. the cloned fragment was found to contain several motifs specific to defence or hormonal response, including a motif involved in the methyl jasmonate reponse, a fungal elicitor responsive element, and tc-rich repeat cis-acting element involved in defence and stress responsiveness. a functional anal ...201122048038
orientation behavior of the predator laricobius nigrinus (coleoptera: derodontidae) to hemlock woolly adelgid and host tree odors in a multi-chambered olfactometer.we studied the adult ambulatory response of the predator, laricobius nigrinus fender (coleoptera: derodontidae), to odors from its prey, adelges tsugae annand, the hemlock woolly adelgid, and foliage of hemlock woolly adelgid, host hemlocks (tsuga spp.), and other conifers. both the predator and hemlock woolly adelgid are apparently native to western north america, but the predator is being released in the eastern united states, which has different hemlock species, for biological control of a l ...201122251687
evaluation of a new battery of toxicity tests for boreal forest soils: assessment of the impact of hydrocarbons and salts.the ability to assess the toxic potential of soil contamination within boreal regions is currently limited to test species representative of arable lands. this study evaluated the use of six boreal plant (pinus banksiana, picea glauca, picea mariana, populus tremuloides, calamagrostis canadensis, and solidago canadensis) and four invertebrate (dendrodrilus rubidus, folsomia nivalis, proisotoma minuta, and oppia nitens) species, and compared their performance to a suite of standard agronomic soil ...201222228553
expression of inducible angiosperm promoters in a gymnosperm, picea glauca (white spruce).electrical discharge particle acceleration was used to test the transient expression of numerous inducible angiosperm promoters in a gymnosperm picea glauca (white spruce). promoter expression was assayed in three different tissues capable of in vitro regeneration, zygotic embryos, seedlings and embryogenic callus. the promoters tested include the light-inducible arabidopsis and soybean ribulose-1,5-bisphosphate small subunit promoters and a maize phosphoenolpyruvate carboxylase promoter; a soyb ...20031868222
identification of defensin-encoding genes of picea glauca: characterization of pgd5, a conserved spruce defensin with strong antifungal activity.plant defensins represent a major innate immune protein superfamily that displays strong inhibitory effects on filamentous fungi. the total number of plant defensins in a conifer species is unknown since there are no sequenced conifer genomes published, however the genomes of several angiosperm species provide an insight on the diversity of plant defensins. here we report the identification of five new defensin-encoding genes from the picea glauca genome and the characterization of two of their ...201223035776
the effects of promoter on transient expression in conifer cell lines.protoplasts from suspension cultures of somatic embryos of white spruce (picea glauca moench voss) were electroporated with plasmids containing the chimeric genes for chloramphenicol acetyl transferase (cat) or β-glucuronidase (gus), under control of one of three promoters. transient cat gene expression of approximately equal magnitude resulted when the cat gene was fused to either the cauliflower mosaic virus (camv) 35s promoter or the nopaline synthase (nos) promoter. when the cat gene was fus ...199024226354
peg-mediated expression of gus and cat genes in protoplasts from embryogenic suspension cultures of picea glauca.ß-glucuronidase (gus) and chloramphenicol acetyl transferase (cat) were used as reporter proteins in protoplasts from embryogenic suspension cultures of picea glauca (moench) voss (white spruce). plasmid dna enclosing chimeric gus and cat constructs, using the cauliflower mosaic virus 35s promoter, was introduced into picea glauca protoplasts using polyethylene glycol (peg). transient expression was detected 12 to 40 h after peg-mediated dna delivery. dose-response curves using covalently closed ...198924240467
links: scalable, alignment-free scaffolding of draft genomes with long reads.owing to the complexity of the assembly problem, we do not yet have complete genome sequences. the difficulty in assembling reads into finished genomes is exacerbated by sequence repeats and the inability of short reads to capture sufficient genomic information to resolve those problematic regions. in this regard, established and emerging long read technologies show great promise, but their current associated higher error rates typically require computational base correction and/or additional bi ...201526244089
cloning and characterization of chitinases from interior spruce and lodgepole pine.chitinases have been implicated in the defence of conifers against insects and pathogens. cdna for six chitinases were cloned from interior spruce (picea glauca x engelmannii) and four from lodgepole pine (pinus contorta). the cloned interior spruce chitinases were annotated class i pgechia1-1 and pgechia1-2, class ii pgechia2-1, class iv pgechia4-1, and class vii pgechia7-1 and pgechia7-2; lodgepole pine chitinases were annotated class i pcchia1-1, class iv pcchia4-1, and class vii pcchia7-1 an ...201424564978
polyamine biosynthesis during somatic embryogenesis in interior spruce (picea glauca x picea engelmannii complex).putrescine, spermidine, and spermine levels during somatic embryogenesis of interior spruce (picea glauca x picea engelmannii complex) were quantified on abscisic acid supplemented growth medium putrescine and spermidine levels increased two-fold coinciding with maturation of the early somatic embryos to globular embryos. polyclonal antibodies raised against escherichia coli arginine decarboxylase (adc) and ornithine decarboxylase (odc), following affinity purification specifically recognized sp ...199624178460
transient gene expression in electroporated picea glauca protoplasts.the reporter gene for chloramphenicol acetyltransferase (cat) was introduced into white spruce (picea glauca (moench) voss.) protoplasts by electroporation. cat transient gene expression was increased by increasing the concentration of pcamvcn plasmid and was affected by the level of the applied voltage. highest cat activities were obtained after electroporation with a pulse of having an exponential decay constant of approximately 105ms. linearized plasmid constructs gave much higher ...198824240396
modelling moose-forest interactions under different predation scenarios at isle royale national park, usa.loss of top predators may contribute to high ungulate population densities and chronic over-browsing of forest ecosystems. however, spatial and temporal variability in the strength of interactions between predators and ungulates occurs over scales that are much shorter than the scales over which forest communities change, making it difficult to characterize trophic cascades in forest ecosystems. we applied the landis-ii forest succession model and a recently developed ungulate browsing extension ...201728263421
tree phyllosphere bacterial communities: exploring the magnitude of intra- and inter-individual variation among host species.the diversity and composition of the microbial community of tree leaves (the phyllosphere) varies among trees and host species and along spatial, temporal, and environmental gradients. phyllosphere community variation within the canopy of an individual tree exists but the importance of this variation relative to among-tree and among-species variation is poorly understood. sampling techniques employed for phyllosphere studies include picking leaves from one canopy location to mixing randomly sele ...201627635335
host species identity, site and time drive temperate tree phyllosphere bacterial community structure.the increasing awareness of the role of phyllosphere microbial communities in plant health calls for a greater understanding of their structure and dynamics in natural ecosystems. since most knowledge of tree phyllosphere bacterial communities has been gathered in tropical forests, our goal was to characterize the community structure and assembly dynamics of phyllosphere epiphytic bacterial communities in temperate forests in quebec, canada. we targeted five dominant tree species: acer saccharum ...201627316353
allometric exponents as a tool to study the influence of climate on the trade-off between primary and secondary growth in major north-eastern american tree species.trees invest in both primary (e.g. height) and secondary (e.g. diameter) growth. the trade-off between these investments varies between species and changes with the tree growing environment. to better establish this trade-off, readily available allometric exponents relating height to diameter at breast height (γ(h,dbh)) and stem volume to diameter at breast height (α(v,dbh)) were simultaneously studied.201626975315
spruce budworm (lepidoptera: tortricidae) oral secretions ii: sessile organisms, plants have evolved different methods to defend against attacks and have adapted their defense measures to discriminate between mechanical damage and herbivory by insects. one of the ways that plant defenses are triggered is via elicitors from insect oral secretions (os). in this study, we investigated the ability of second-instar (l2) spruce budworm [sbw; choristoneura fumiferana (clemens)] to alter the volatile organic compounds (vocs) of four conifer species [abies balsa ...201526454474
a molecular identification protocol for roots of boreal forest tree species. 201425383267
biogeographic variation in evergreen conifer needle longevity and impacts on boreal forest carbon cycle projections.leaf life span is an important plant trait associated with interspecific variation in leaf, organismal, and ecosystem processes. we hypothesized that intraspecific variation in gymnosperm needle traits with latitude reflects both selection and acclimation for traits adaptive to the associated temperature and moisture gradient. this hypothesis was supported, because across 127 sites along a 2,160-km gradient in north america individuals of picea glauca, picea mariana, pinus banksiana, and abies b ...201425225397
a large herbivore triggers alternative successional trajectories in the boreal forest.alternative successional trajectories (ast) may result in multiple climax states within an ecosystem when disturbances affect colonization history. in the boreal forest, ungulates have been proposed to drive ast because, under herbivore pressure, preferred species may go extinct and apparent competition may benefit browsing-resistant species. over a 15-year period following logging, we tested whether deer herbivory altered plant species composition and whether the competitive advantage of resist ...201324597230
the action of antidiabetic plants of the canadian james bay cree traditional pharmacopeia on key enzymes of hepatic glucose homeostasis.we determined the capacity of putative antidiabetic plants used by the eastern james bay cree (canada) to modulate key enzymes of gluconeogenesis and glycogen synthesis and key regulating kinases. glucose-6-phosphatase (g6pase) and glycogen synthase (gs) activities were assessed in cultured hepatocytes treated with crude extracts of seventeen plant species. phosphorylation of amp-dependent protein kinase (ampk), akt, and glycogen synthase kinase-3 (gsk-3) were probed by western blot. seven of th ...201323864882
antioxidant potential of bark extracts from boreal forest conifers.the bark of boreal forest conifers has been traditionally used by native americans to treat various ailments and diseases. some of these diseases involve reactive oxygen species (ros) that can be prevented by the consumption of antioxidants such as phenolic compounds that can be found in medicinal plants. in this study, ultrasonic assisted extraction has been performed under various solvent conditions (water:ethanol mixtures) on the bark of seven boreal forest conifers used by native americans i ...201326784337
episodic recruitment of the seedling banks in balsam fir and white spruce. 201223204491
recovery kinetics of photochemical efficiency in winter stressed conifers: the effects of growth light environment, extent of the season and species.evergreens undergo reductions in maximal photochemical efficiency (f(v)/f(m)) during winter due to increases in sustained thermal energy dissipation. upon removing winter stressed leaves to room temperature and low light, f(v)/f(m) recovers and can include both a rapid and a slow phase. the goal of this study was to determine whether the rapid component to recovery exists in winter stressed conifers at any point during the season in a seasonally extreme environment. additional goals were to comp ...201322575048
carry-over effect of host nutritional quality on performance of spruce budworm progeny.the effect of host nutritional quality on spruce budworm (choristoneura fumiferana (clemens)) parental and offspring performance was studied using field and laboratory rearing experiments, and foliar chemical analyses. foliage of balsam fir (abies balsamea (l.) mill.), white spruce (picea glauca (moench) voss) and black spruce (p. mariana (mill.) bsp) was used to rear the parental generation in the field, whereas an artificial diet was used to rear the progeny under laboratory conditions. import ...201222077965
reproductive potential of balsam fir (abies balsamea), white spruce (picea glauca), and black spruce (p. mariana) at the ecotone between mixedwood and coniferous forests in the boreal zone of western quebec.the reproductive potentials of balsam fir and white spruce (co-dominants in mixedwood forests) and black spruce (dominant in coniferous forests) were studied to explain the location of the ecotone between the two forest types in the boreal zone of quebec. four sites were selected along a latitudinal gradient crossing the ecotone. cone crop, number of seeds per cone, percentage filled seeds, and percentage germination were measured for each species. balsam fir and white spruce cone crops were sig ...200721636443
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