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The in-vitro culture of arbuscular mycorrhizal fungi on excised roots, especially when performed on bi-compartmented Petri dishes, has proven to be an efficient system for the production of root-free fungal material. However, even after the contact between fungal hyphae and the excised roots in the proximal root compartment has occurred, up to several weeks may be required for the fungal runner hyphae to cross the median Petri dish wall and reach the distal fungal compartment. This delay is particularly long for the cultivation of slow-growing strains that usually colonize the substrate less aggressively. The delay is due to the difficulty the runner hyphae have in crossing the median Petri dish wall that separates compartments. To facilitate the passage of the fungus across the median wall, a “paper bridge” system has been devised and tested with a number of arbuscular mycorrhizal fungal strains. This method substantially accelerated fungal propagation and simplified the manipulations necessary. The proposed paper-bridge system is described and its advantages discussed. La culture in vitro des champignons mycorhiziens arbusculaires sur racines excisées, notamment en boîtes de Petri bi-compartimentées, constitue un système efficace de production axénique de champignon. Bien que le contact hyphe-racines s’effectue rapidement dans le compartiment racine, plusieurs semaines peuvent être requises par les hyphes pour traverser dans la partie distale du système. Ce délai, particulièrement long pour les souches à croissance lente et peu agressives, est dûprincipalement à la difficulté pour les hyphes de traverser la cloison centrale qui sépare les compartiments. Afin de remédier à cette difficulté un « pont de papier » testé sur une diversité de souches mycorhiziennes s’est avéré efficace pour accélérer la propagation fongique tout en simplifiant substantiellement les manipulations. Le système est décrit et ses avantages discutés. [ABSTRACT FROM AUTHOR]

Extensive 14C dating and botanical identification of charcoal fragments located in the organic surface soil layer and buried in the mineral podzolic solum were used to reconstruct the successional pathways of a balsam fir forest site. The studied forest site developed in a context of continuous fire disturbance over the last 9000 years with at least 26 fires occurring at a mean interval of 330 years. Tree vegetation of the site followed a four-step trajectory consisting of an early-Holocene spruce forest and a late-Holocene mixedwood balsam fir forest. Boreal-like spruce-birch and temperate-like white pine-birch forests dominated the site between 7900 and 5900 cal. B.P. and 5600 and 1275 cal. B.P., respectively. Because all forest types developed repeatedly after fire since early deglaciation, changes in forest composition, in particular the shift of white pine forest to balsam fir forest, and concurrent decline of birch (yellow birch and/or paper birch) and pine populations were most likely related to progressive cooler and wetter conditions from mid- to late Holocene. Fire disturbance on this part of the southern boreal biome has been a continuous, positive regenerative process over the Holocene, allowing the successional turnover of boreal and temperate trees under the influence of climatic change. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses articles in the issue on topics including dwarf mistletoes, research papers and pathogenic microorganisms.

In several gymnosperm tree species of the circumboreal forest, reproductive development is closely associated with the accumulation of degree-days during the growing season. We wanted to verify whether this pattern holds for a widespread angiosperm species such as paper birch (Betula papyrifera Marsh), a broadleaf tree distributed throughout the North American boreal forest. Stations to simultaneously measure the thermal sum (degree-days > 5 °C, DD) and the reproductive development (anatomical development and seed germination) were installed in four sites along an altitudinal thermal gradient totalling 541 m a.s.l. in the eastern Appalachian Mountains (Canada). In 2004, sites 1, 2, 3 and 4, received 973, 1099, 1266 and 1359 DD, respectively. A strong relationship was found between thermal sum and reproductive development (anatomical development: r2 > 0.90; seed germination r2 > 0.72). This relationship seems to be based on the absolute value of heat-sum received because (i) rates of reproductive development are twice as high in colder sites (1 and 2) than in warmer sites (3 and 4), and (ii) total seed germination did not differ among the sites. Along with this, we noted a lesser production of full seeds in colder sites, coupled with a higher success of germination in the coldest site (site 1), which appears to be a mechanism of phenotypic adaptation to cold. [ABSTRACT FROM AUTHOR]

The article presents information on the paper awards presented by the journal "Botany," where the journal recognizes the works of students and professors in different fields of study. The J. Stan Rowe award is presented to the students in the field of plant ecology and the Taylor A. Steeves award is presented students with botany as a subject. Information on the eligibility that includes the bona fide of the students and the evaluation of the students is also presented.

Seeking to generate a deeper methodological and theoretical dialogue between botanical science and anthropology, this paper summarizes interdisciplinary approaches to human–plant interactions we have described as "sensory ecology" and "phytoethnography", applying these concepts to vital questions about human–plant relations in Amazonia. Building on this work, we broaden the scope of our investigations by considering their relevance to the field of historical ecology. In particular, we discuss Eduardo Viveiros de Castro's concept of "multinaturalism" and explore how it can be applied to understanding management and domestication of forest landscapes in Amazonia by Indigenous Peoples. [ABSTRACT FROM AUTHOR]

Calea ternifolia Kunth (Asteraceae), the "dream herb", is an important medicinal plant that grows from Mexico to Costa Rica. The plant is highly valued for rituals and for treating several illnesses including anorexia, upset stomach, diabetes, periodic fevers, diarrhea, bile problems, and skin diseases. This comprehensive literature survey on C. ternifolia was performed up to January 2021. Our review focuses on traditional uses, botanical aspects, chemical constituents, quality control tests, as well as pharmacological and toxicological studies. Data were recorded using online scientific databases including Scopus, PubMed, Google Scholar, Taylor and Francis Imprints, National Center for Biotechnology Information, Science Direct, JSTOR, and SciFinder. The information was assembled from research articles, relevant books on herbal medicinal plants and the history of medicinal plants from Mexico, theses, reports, and web pages. The more significant botanical and ethnomedical aspects were recorded including the discovery of the oneirogenic use (enhancer of dreams) of C. ternifolia by the Chontal Indigenous communities in Oaxaca, Mexico. The plant contains sesquiterpenes and flavonoids as the major constituents. Some properties associated with the plant's traditional uses have been demonstrated including spasmolytic, antidiabetic, antidepressant, anti-inflammatory, and antinociceptive effects. The plant's toxicity will be discussed in this paper. Solid pharmacological research provided evidence supporting the use of the dream herb for oneiromancy. [ABSTRACT FROM AUTHOR]

This paper describes the importance of fungi to Canadian Indigenous Peoples. Based on collaborative research with Indigenous knowledge holders and a review of literature, approximately 30–40 fungi are documented as having cultural roles for Canadian Indigenous groups. Some peoples have not eaten mushrooms traditionally, whereas others have a history of harvesting, cooking, storing, and trading mushrooms for their diets. Perennial tree fungi have application as tinder, fire starter, and for carving masks. They also have a range of medicinal uses, some being consumed as medicinal teas, and others applied externally, in some cases by moxibustion to relieve underlying pain. Puffballs also have a range of material and medicinal applications, especially for stopping haemorrhages. Fungi are widely known for spiritual or sacred associations and play key roles in rituals, ceremonies, stories, and beliefs, which are also reflected in the names of some species. The antiquity of peoples' relationships with fungi is likely very deep, extending back to ancient Asian or European ancestors of Pleistocene times, whose descendants on those continents have used them in similar ways. Fungi continue to play important roles for Indigenous Peoples today, with some being harvested commercially, and many still used in traditional ways. [ABSTRACT FROM AUTHOR]

Lentil (Lens culinaris Medik.) is one of the most important food legumes in the world that can contribute to food security and sustainable farming. Drought tolerance is one of the major objectives of breeding programs. This research paper aimed at comparing genotypes with different genetic background (landraces, Lens orientalis wild accessions, and elite advanced lines) under 2 watering regimes (well-watered and progressive water deficit). Drought tolerance was assessed based on morphological and physiological parameters: relative water content and water loss rate of leaves, cell membrane stability, canopy temperature, root/shoot ratio, seedling vigor, wilting severity, and harvest index. The evaluation was carried out in a greenhouse pot experiment using 3 replications. Wild accessions were more drought tolerant than advanced lines and landraces. They had higher root/shoot ratios, relative water contents of leaves, canopy temperature depressions, and cell membrane stability, and lower wilting severity and water loss rate of leaves. In fact, discriminant factor analysis highlighted a clear genetic differentiation for drought tolerance between the 3 genetic groups. Different morpho-physiological responses of the studied genetic material have been observed corresponding to different drought tolerance mechanisms. Wild accessions, advanced lines, and new National Institute of Agricultural Research (INRA) of Morocco varieties A3, A4, A5, A6, and A7, as well as lentil of Zaer, a specific landrace with specific quality mark distinction known in the country, were identified as the most drought tolerant among the studied genetic material. These accessions could be used in genetic improvement programs from the perspective of developing drought tolerant varieties. [ABSTRACT FROM AUTHOR]

Regional and global biodiversity may be underestimated due to the presence of cryptic species: species that are morphologically similar, but genetically distinct. Here, we focus on two cryptic duckweed species, Lemna minor L. and Lemna turionifera Landolt, which have overlapping geographic ranges and are easily mistaken for one another. We developed species-specific primers based on DNA barcoding sequences to facilitate the rapid identification of these two monomorphic duckweeds, allowing us to investigate their presence and distribution in Alberta, Canada. While current reports indicate the presence of L. turionifera (and the morphologically distinct Lemna trisulca L.) in Alberta, our data indicate that L. minor is also present, predominantly in the southern part of the province. Thus, this paper (i) contributes to the accuracy and completeness of a regional flora, and (ii) provides useful and flexible tools for the rapid molecular identification of cryptic Lemna species, which are of wide interest in diverse fields such as biotechnology, toxicology, bioremediation, and ecology. [ABSTRACT FROM AUTHOR]

To investigate the interactive effects of soil temperature (Tsoil) and nutrient supply on the responses of growth and biomass of white birch (Betula papyrifera Marsh.) to atmospheric carbon dioxide concentration ([CO2]), seedlings were grown under two [CO2] (360 and 720 µmol·mol–1), three Tsoil (5, 15, and 25 °C initially, increased to 7, 17, and 27 °C one month later), and three nutrient regimes (Low: N–P–K = 4:1.8:3.3 mg·L–1; Intermediate: N–P–K = 80:35:66 mg·L–1; and High: N–P–K = 160:70:132 mg·L–1) for 4 months. Low Tsoil reduced leaf and total biomass at high nutrient supply and root biomass at intermediate and high nutrient supply. There were significant three-factor interactive effects on root collar diameter (RCD), stem biomass, and leaf mass ratio. Low Tsoil reduced RCD at high nutrient supply and stem biomass at intermediate and high nutrient supply in elevated [CO2] while intermediate and high Tsoil enhanced them. Values of leaf mass ratio were lowest at low Tsoil and low nutrient supply in elevated [CO2]. The effect of Tsoil was generally insignificant at low nutrient supply, but the responses of growth and biomass remained significantly higher under high than low nutrient supply at all Tsoil. [ABSTRACT FROM AUTHOR]

The hemiparasitic European mistletoe, Viscum album L. (Viscaceae), displays a rapid and remarkable expansion into natural and urban ecosystems in Ukraine. The monitoring and management of this quickly spreading species is becoming increasingly difficult as new plant species become hosts. Unlike other local mistletoe species, the European mistletoe has a broad distribution and thus requires a countrywide pest status assessment for control. This review outlines the major taxonomic and evolutionary issues pertinent to V. album with an emphasis on the characters used to distinguish its five currently recognized subspecies. The review also provides an updated distribution map and host range for the three V. album subspecies in Ukraine [V. album subsp. album, V. album subsp. abietis (Wiesb.) Janch., and V. album subsp. austriacum (Wiesb.) Vollm.], addressing the current knowledge of their biology and ecology. A significant portion of the paper is devoted to the diversity of organisms associated with V. album, including herbivores, endophytes, and parasites, drawing particular attention to major pollination and dispersal vectors, as well as potential biocontrol agents for this mistletoe species. [ABSTRACT FROM AUTHOR]

Owing to changing weather patterns, catastrophic natural disasters are expected to happen more frequently and cause dramatic life and economic losses worldwide. The United States experienced a historically high record of weather disasters in 2017, with the economic losses exceeding 300 billion dollars. A major contributor to economic loss and threat to public safety is damage, destruction, and failure of civil structures in the strong-wind dominated disasters. There is a pressing need for reconstruction and redesign of critical civil structures to better cope with high winds to mitigate the loss of lives and properties. This paper takes a biomimetic perspective to link problem areas with potential solutions for future bio-inspired technology development, by identifying the most vulnerable aspects of civil structures in strong winds on one side and wind-resilient examples of biological systems on the other side. Of particular interest are plants that thrive in high winds, as they have likely adapted to manage the harsh environment under pressure of natural selection. Specific biological examples include the Saguaro cactus (Carnegiea gigantean Britton & Rose), reed grass, and shape reconfiguration of leaves. A review of problem areas, abstracted principles, and exemplary biological role models shall inform and guide towards new designs of wind-resilient civil structures. [ABSTRACT FROM AUTHOR]

We developed a method combining passive baiting (animals that are not trapped) with DNA meta-barcoding of the feces acquired, to study fungi in the diet of small mammals. Mammal and fungal species were identified using genomic DNA of 596 fecal samples collected in five regions of the eastern Canadian boreal forest. For identification of the small mammal species, the cytochrome b region was used. A total of eight species of small mammals displayed hypogeous fungi consumption, with northern flying squirrels (Glaucomys sabrinus) and red-backed voles (Myodes gapperi) as the top consumers. For identification of their fungal diets, the ribosomal internal transcribed spacer (ITS) region was used. We recovered 722 taxa of Ascomycota, 429 Basidiomycota, 81 Zygomycota, 4 Chytridiomycota, 1 Glomeromycota, and 44 unidentified fungal taxa. Of these, 28 were hypogeous sequestrate fungi (underground fructification), which presumably are dug out by small mammals for consumption. Otherwise, for the remaining fungi [epigeous (above ground fructification) or microscopic fungal species], it is unclear which ones are selected by the animal as a dietary source or result from incidental contamination. Our paper presents a promising approach for tracing mycophagy in small mammals, and our results suggest that fungal diversity is important for the diet of some small mammals. [ABSTRACT FROM AUTHOR]

Today, scattered disjunct stands of two temperate species, yellow birch and white pine, are present north of their continuous distributional range in southern Quebec (Canada) at topographical locations that offer protection from severe fires. This study tested whether these species had populations more numerous and widespread millennia ago when the climate was presumably warmer. Specifically, this research involved the analyses of pollen, plant macrofossils, and charcoal fragments of two sites within the western part of Quebec's balsam fir - paper birch bioclimatic domain: a forest humus deposit from a yellow birch stand (local scale), and a peatland (regional scale). Fossil data suggest that white pine was more abundant regionally between 7500 and 5000 cal. BP, before coming rare under subsequent cooler conditions. Likewise, yellow birch was more abundant regionally between 7700 and 1500 cal BP. Its subsequent decline and the local disappearance of white pine by ∼200 cal. BP may both be explained by the severe fires that occurred in recent centuries, as well as the rarity of suitable habitats for these species. The sustained presence of temperate species in mixed boreal forests is the result of the combined action of climate, natural disturbances and habitat characteristics. [ABSTRACT FROM AUTHOR]

A growing appreciation of the intimate association between trees and a wide diversity of mycorrhizal fungi in forest ecosystems is leading to the view that trees and their associated mycorrhizal symbionts should be considered meta-organisms or holobionts. For ectomycorrhizal associations, nitrogen (N) mobilization and uptake is a major contribution from the fungal partners. This paper reviews the traditional methods of measuring N uptake by ectomycorrhizae, and describes the application of microelectrode ion flux measurement of nitrogen uptake using the MIFETM technique to ectomycorrhizal fungi associated with forest trees. From results obtained with microelectrode ion flux measurement thus far, we argue that plant N uptake capacity should be considered an exogenous trait, related to the functional diversity among ectomycorrhizal species and communities, rather than a function of host plant root physiology, alone. [ABSTRACT FROM AUTHOR]

Invasiveness has usually been studied as a species-level attribute; nevertheless, phenotypic differences between individuals in a population can lead to significant variations in colonization ability. In this paper, we analyse the potential effects of sex morphs of Prunus mahaleb L., a gynodioecius fleshy-fruited tree, on its invasiveness in natural grasslands in the southern Argentine Pampas. We assessed the abundance of both hermaphrodite and female plants, and compared their fecundity, propagule size, and germination response. We found that the females were less abundant in the invasive populations studied, apparently since the beginning of the colonization. However, our results demonstrated that at the present time, females do not show any fecundity reduction, which clearly shows that P. mahaleb has established an effective interaction with generalist pollinators that compensates for the apparently disadvantaged females. Fruit set showed a wider range of variability over time in the females than in the hermaphrodites, which could be the consequence of greater susceptibility to changes in the activity of pollinators. We found no evidence of a female benefit due to reallocation of resources or better outcrossed progeny when considering propagule size and germination. We discuss the relative importance of sex morphs and interactions at different stages of the invasion process. [ABSTRACT FROM AUTHOR]

Spring ephemerals take advantage of the high light conditions in spring to accumulate carbon reserves through photosynthesis before tree leaves unfold. Recent work has reported delayed leaf senescence under constant light availability in some spring ephemerals, such as wild leek ( Allium tricoccum). This paper aims to establish whether tree canopy composition and phenology can influence the growth of spring ephemerals through changes in their phenology. Wild leek bulbs were planted in 31 plots in southern Quebec, Canada, under canopies varying in composition and densities. Light availability and tree phenology were measured, along with other environmental conditions, and their effect on the growth of wild leeks was assessed with a redundancy analysis. Higher light availability resulted in better growth of wild leeks. The plants postponed their senescence under trees with late bud-burst, and thus better bulb growth and seed production were achieved. The tree litter and temperature and moisture levels of the soil also influenced the growth and survival of wild leeks. Thus, tree leaf phenology appears to have a strong impact on the growth of spring ephemerals by modulating the length of their growing season and their photosynthetic capacity. This underlines the importance of considering the variation of light availability throughout the growing season in the study of spring ephemerals. [ABSTRACT FROM AUTHOR]

γ-Aminobutyrate (GABA) is a ubiquitous nonprotein amino acid that accumulates in plants in response to abiotic and biotic stresses. In a companion paper, we discussed the origin of GABA from glutamate and subsequent catabolism to succinic semialdehyde and either succinate or γ-hydroxybutyrate (GHB), and the characteristics of genes and proteins responsible for GABA permease, glutamate decarboxylase, GABA transaminase, succinic semialdehyde dehydrogenase, and succinic semialdehyde reductase activities. In this paper, we explore gene expression and transcript-metabolite relationships during the response to abiotic stress, and describe phenotypes of genetic mutants and relationships of GABA metabolism to other plant functions. Evidence indicates that both gene-dependent and -independent processes are involved in the response of the GABA pathway to abiotic stresses. Study of stress-specific responses and their interplay with the C/N network and various signalling pathways would be more informative if circadian rhythms and light-dark transitions upon imposition of the stress were always taken into account, and relevant genes and metabolites simultaneously profiled in wild-type plants or genetic mutants. [ABSTRACT FROM AUTHOR]

Substratum plays an important role in saxicolous lichen communities, providing a stable growth surface for long-term attachment and influencing the relative abundance of species. Saxicolous lichen communities consisting of Xanthoparmelia and Arctoparmelia were previously characterized using thallus cover on the substratum as well as lichen fecundity, but it was not known whether the substratum influenced lichen fecundity. The objectives of this paper were to compare variation in element concentrations among lichen communities, and to examine the correlation between elemental composition and percent cover and fecundity (numbers of apothecia, ascospores, and percent germination) of each of three lichens Arctoparmelia centrifuga, Xanthoparmelia viriduloumbrina, and X. cumberlandia. Percent cover and fecundity features were compared with the rock type and 21 elements from 37 transects. Element concentrations varied among communities, but the grassy rock community had significantly higher concentrations of elements than the mossy or treed rock communities. Positive correlations were present between fecundity and particular elements for the three species. This study provides insight into the complexity of the relationship between the geological composition of the substratum and saxicolous lichen biology. [ABSTRACT FROM AUTHOR]

Biomass equations are essential for evaluating the climate change mitigation potential of forests through biomass accumulation and carbon sequestration. In northern Iran's Hyrcanian forests, topographic relief is so extreme that developing biomass equations from destructive sampling of trees is physically challenging. In this paper, allometric biomass and leaf area equations were developed for three common Hyrcanian tree species: Oriental beech ( Fagus orientalis Lipsky), chestnut-leaved oak ( Quercus castaneifolia C.A.Mey.), and common hornbeam ( Carpinus betulus L.). A total of 30 trees, ranging in diameter at breast height (DBH) from 21 to 90 cm, were felled and stems, branches, twigs, and leaves from each tree were measured and weighed. Allometric equations for estimating biomass from DBH and height and their combinations were derived. Model comparison and selection were based on R2, Akaike's information criterion (AIC), prediction error sums of squares, model standard error estimate (SEE), ΔAIC, and correction factor. The best-fit equations had adjusted R2 values between 0.81 to 0.98 and SEE values between 0.351 and 0.681. The allometric equations provide improved methods for predicting forest biomass and carbon storage in Hyrcanian forests from standard forestry measurements, which means these equations may be applied to historical and new forest data. [ABSTRACT FROM AUTHOR]

Studies on floral development have widened the knowledge on the floral morphology of Araceae, particularly in genera delimited through classical taxonomic treatments. In Pothoideae, floral ontogenetic studies are limited to some representatives of Pothoidium Schott and Pothos L. and only one species of Anthurium Schott, with no focus on gynoecium. This background reveals a lack of ontogenetic data on the largest genus in the clade. This paper presents gynoecial ontogeny of species circumscribed in different sections of Anthurium, describes gynoecial developmental patterns, and evaluates the relevance of ontogenetic characteristics in the taxonomy of the sections studied. New data for the Araceae include the recognition of four floral developmental phases, the carpellary nature of the ovarian septum, and the development of the symplicate and synascidiate zones of the gynoecium. The apical septum described in Anthurium scandens (Aubl.) Engl. is first reported for the genus in this study. We also highlight the importance of these ontogenetic data as new information for the Pothoideae within Araceae and to understand the notable phases of floral development in the reproductive biology of Anthurium. [ABSTRACT FROM AUTHOR]

Abstracts of papers presented at the 50th Meeting of the Canadian Botanical Association are presented which include one on understanding the source of methane emissions from plants, nitrogen transporters expression in salt-tolerant and salt-sensitive tomato plants, and population structure of the boreal felt lichen in ribbed moraine landscape of Eastern Newfoundland.

The discovery of biotic and ecological factors that influence genetic isolation in populations contributes to our understanding of speciation, one of the most important issues in evolutionary biology. In this paper, we ask whether differences in climate preferences are influencing genetic isolation in two assemblages of populations of Berberis trifoliolata Moric., the Northeastern and the Mexican Plateau groups. Agarito, as this species is known, is a remarkable shrub in the arid regions of North America and found mostly in the Chihuahuan Desert. Ecological niche modeling and two tests of niche evolution were carried out. The Ecological Niche Modeling suggests that the potential distribution of the Northeastern group does not predict that of the Mexican Plateau group, and nor does the latter predict the former. Tests of niche evolution indicate a divergent niche between these two groups. Among the most important climate factors detected in the multivariate niche evolution test are mean annual temperature and annual precipitation. We concluded that the two lineages exemplify an incipient speciation process. [ABSTRACT FROM AUTHOR]

Native ectomycorrhizal fungi (ECMF) represent an emergent critical support in forestry and bioindustry while providing an attractive economical return and ecosystems services. These attributes are desirable given the human activities that are affecting ecosystems and biodiversity worldwide. The Mediterranean region has inherited native forests that are in serious decay, with serious environmental and socioeconomic consequences as a result of human influence in shaping ecosystems, particularly over the last century. In this context, edible ECMF are important not only because of their value for ecosystem functions, but also for their organoleptic and nutritive properties, and because of the presence of bioactive compounds. In this paper, we discuss critical aspects of ECMF diversity and traits for forest health, productivity, and sustainability, as well as the importance of exploring biologically active proteins obtained from native ECMF as sources for future forest management planning and industry innovation. The use of convergent approaches to ameliorate the identity of ECMF reservoirs in forest ecosystems and rural lands is urgently required to restore and protect native biodiversity and ecosystems services and meet efficient production solutions to provide sustainable innovation while ensuring environmental safety. [ABSTRACT FROM AUTHOR]

Many rare plant species are declining owing to habitat destruction and degradation. Because many populations of rare species suffer low recruitment, a good understanding of seed ecology is crucial for developing effective conservation and management plans. In this study, we examine the effects of shading, seed longevity, and soilless mixes on seed germination for the rare midwestern USA endemic Synthyris bullii (Eaton) A. Heller. Seed germination studies were conducted in a greenhouse environment utilizing seeds from populations collected in Illinois in 2008, 2009, and 2010. In the shading study, both control (66.7% ± 1.3%) and green wrap (63.7% ± 1.3%) had similar and greater percent seed germination than the solid white wove paper (59.5% ± 1.3%). Percent seed germination was similar for seeds collected in 2010 and 2009 (59.5% ± 3.3% and 55.1% ± 4.4%, respectively) in the longevity study, but germination was lower for seeds collected in 2008 (27.1% ± 4.0%) compared with both of the other years. For the soilless mixes study, seeds sown in only one of the three media, Fafard Super-Fine Germinating Mix, emerged (3.5% ± 1.0%). Results from these studies suggest that for S. bullii, ( i) seeds may be shade tolerant, (ii) seed viability lessens with age, and ( iii) seedlings require a special soilless mix to grow. The information generated by this study can provide guidelines for better seed storage and germination protocols for the conservation of this rare plant species. [ABSTRACT FROM AUTHOR]

The present paper reports our observations on the mode of reproduction in Taraxacum udum (sect. Palustria), a very rare species in Poland, known only from a single locality. Based on the analysis of the developmental processes in the ovules, it can be concluded that this bog dandelion is an obligate and autonomous apomict. Its reproduction involves ( i) restitutional diplospory, also known as Taraxacum type; ( ii) parthenogenesis; and ( iii) autonomous endosperm formation. Moreover, observations on the anatomy of ovules confirmed the occurrence of a special storage tissue around the embryo sac, which is considered to be an additional source of nutrition for the embryo. An examination of the anthers showed that, in spite of highly disturbed meiosis, apomictic T. udum produces pollen but pollen grains are heterogeneous in size and stainable using an acetocarmine test. [ABSTRACT FROM AUTHOR]

Reported from marine, freshwater, and terrestrial habitats, trichomycetes are an ecological group of both fungi and protists that colonize the guts of insects, crustaceans, and millipedes. Lotic sites (streams, rivers) are a rich source of hosts and their trichomycetes. As part of a larger study of trichomycetes from different aquatic habitats within the Halifax Regional Municipality in Nova Scotia, Canada, one stream from each of three separate watersheds was sampled for aquatic insects, and their guts were dissected and examined for microscopic trichomycetes. Over the course of 17 months, 24 species of trichomycetes were collected including the following four new species: Glotzia gemina sp. nov. R.T. William and Strongman from a mayfly (Baetidae); Stachylina tanysoma sp. nov. R.T. William and Strongman; Smittium ampliboja sp. nov. R.T. William and Strongman; and Smittium insolitum sp. nov. R.T. William and Strongman, all recovered from dipteran (Chironomidae) hosts. New continental records were established for three species including Smittium pusillum Manier & Coste and Stachylina euthena Manier & Coste, both originally described from France, and Smittium nodifixum Strongman & Shengquan Xu previously known only from China. A new regional geographical record for Pennella arctica Lichtw. & M.C. Williams is reported and 17 other species previously known from eastern Canada were recorded. Pteromaktron timberleaense R.T. William & Strongman was described by us from Timberlea, Nova Scotia, but at the time no sexual spores (zygospores) were seen. In the collections reported in this paper, zygospores were found so the original description is emended to include the zygospore features for this species. This report adds to the published data on trichomycetes from Nova Scotia that have appeared over the last 10 years and highlights the significance of long-term sampling in cataloguing the diversity of this group of insect associated microorganisms. We also present some data on seasonal variation in trichomycete occurrence and comment on site specificity in the trichomycetes we collected. [ABSTRACT FROM AUTHOR]

γ-Aminobutyrate (GABA) is a ubiquitous four-C, nonprotein, amino acid that has been linked to stress, signaling, and storage in plants. In this paper, we discuss analytical, enzyme-linked, and colorimetric methods for analyzing GABA and related metabolites, and review tracer evidence for the derivation of GABA from glutamate and its subsequent catabolism to succinic semialdehyde and either succinate or γ-hydroxybutyrate. Also, we describe biochemical, complementation, bioinformatic, recombinant, and modelling strategies for identifying genes and investigating properties of the encoded proteins responsible for transport and metabolism of GABA. For Arabidopsis, evidence supports the involvement of a plasma membrane GABA transporter, a mitochondrial GABA permease, a cytosolic Ca2+/calmodulin- and pH-regulated cytosolic glutamate decarboxylase, a pyruvate- and glyoxylate-regulated mitochondrial GABA transaminase, a redox-regulated mitochondrial succinic semialdehyde dehydrogenase, and redox-regulated glyoxylate/succinic semialdehyde reductases located in both cytosol and plastid, respectively. This simple biochemical model does not account for species and tissue differences in the isoform complement of GABA pathway enzymes or transcriptional control of the pathway. In a companion review, we provide a more integrated view of GABA metabolism and function. [ABSTRACT FROM AUTHOR]

In this paper we investigate the effects of bird ingestion on Vaccinium cylindraceum Smith seed germination characteristics and the effect of a lack of bird dispersal on seed germination in the field. To test the effect of bird ingestion on seed germination, we carried out laboratory germination trials using ingested seeds and manually depulped seeds. To test the effect of a lack of bird dispersal on seed germination, we carried out germination trials using intact fruits above or under a cap of dead leaves under field conditions. The number of damaged seeds per fruit differed between species. Nearly 92% and 70% of the seeds ingested by, respectively, Erithacus rubecula and Turdus merula passed intact through the birds' digestive tracts, and the germination characteristics of these seeds were not significantly affected. Only 16% of the seeds ingested passed intact through the digestive tract of Fringilla coelebs, and the germination ability of these seeds was significantly reduced. Uncovered intact berries in the field cracked, exposing the seeds to light, thus resulting in 18% of germination. Our results suggest that E. rubecula, T. merula, and F. coelebs can act as seed dispersers of V. cylindraceum. Also, V. cylindraceum seeds do not need to be ingested to germinate, but seed germination is enhanced as a consequence of seed exposure to light. [ABSTRACT FROM AUTHOR]

Resource sharing between connected ramets can be advantageous for clonal plants. However, widespread vascular integration bears the risks of enhanced internal pathogen spread, which may be one of the most prominent disadvantages of clonal growth. In this paper we analyzed patterns of internal virus spread in ramet groups of the stoloniferous herb L. (white clover) and investigated the effect of leaf ontogeny on intraclonal disease development. We inoculated single leaves of T. repens with White clover mosaic virus and analyzed the infection status of ramets at different distances from the point of infection and in leaves from different developmental stages. White clover mosaic virus infected all young developing plant parts positioned on basal branches or on the main stolon. Leaf ontogeny strongly affected disease development, and fully mature leaves on the main stolon remained virus free. The pattern of plant-internal virus spread was not affected by heterogeneous light conditions. Despite the well-described advantages of physiological integration, our data suggest that clonal integration may lead to negative selection pressures on clonal growth in pathogen-prone environments. [ABSTRACT FROM AUTHOR]

The bryological history of Washington State, USA, is scattered and not well organized. An overall study of the moss flora within the San Juan Islands led to extensive searches of the major regional herbaria and a review of the relevant literature. This paper provides the foundation for a complete bryophyte history and moss flora of the state and reports new records of three species, Drepanocladus crassicostatus Janssens, Orthotrichum hallii Sull. & Lesq. in Sull., and Syntrichia papillosa (Wilson) Jur., and one variety, Syntrichia laevipila Brid. var. meridionalis (Schimp.) Wijk & Marg., for Washington. Les documents historiques sur la bryologie de l’état de Washington aux tats-Unis, sont dispersés et mal organisés. Une étude sur l’ensemble de la flore muscinale des îles San Juan a fourni l’occasion d’examiner les principaux herbiers régionaux et de revoir la littérature pertinente. Cette publication constitue la base pour construire une histoire complète des bryophytes et la flore muscinale de l’état et rapporte de nouvelles mentions pour trois espèces, les Drepanocladus crassicostatus Janssens, Orthotrichum hallii Sull. & Lesq. in Sull., et Syntrichia papillosa (Wilson) Jur., et une variété, le Syntrichia laevipila Brid. var. meridionalis (Schimp.) Wijk & Marg., pour Washington. [ABSTRACT FROM AUTHOR]

Azospirillum spp. are plant growth promoting bacteria (PGPB) that enhance growth by several mechanisms, including the production of phytohormones such as abscisic acid (ABA), indole-3-acetic acid (IAA), and gibberellins (GAs). Their presence may also alleviate plant water stress. In the present paper, the effects of Azospirillum lipoferum in maize (Zea mays L.) plants treated with inhibitors of ABA and GA synthesis, fluridone (F) and prohexadione-Ca (P), respectively, and either submitted to drought stress or provided sufficient water, were analysed. Fluridone diminished the growth of plants that had been well watered, in a manner similar to drought, but inoculation with Azospirillum completely reversed this effect. The relative water content of the F-treated and drought-stressed plants was significantly lower (even though drought-stressed plants had been allowed to recover for one week), and this effect was completely neutralized by Azospirillum. These results were correlated with ABA levels assessed by GC-EIMS. Growth was diminished in drought-submitted plants treated with P, alone or combined with F, even though ABA levels were enhanced, suggesting that GAs produced by the bacterium are also important in stress alleviation. The results suggest that both ABA and GAs contribute to water-stress alleviation of plants by Azospirillum. [ABSTRACT FROM AUTHOR]

Diatom taxa present in the inland streams and lakes of the McMurdo Dry Valleys and James Ross Island, Antarctica, are presented in this paper. A total of nine taxa are illustrated, with descriptions of four new species (Luticola austroatlantica sp. nov., Luticola dolia sp. nov., Luticola laeta sp. nov., Muelleria supra sp. nov.). In the perennially ice-covered lakes of the McMurdo Dry Valleys, diatoms are confined to benthic mats within the photic zone. In streams, diatoms are attached to benthic surfaces and within the microbial mat matrix. One species, L. austroatlantica, is found on James Ross Island, of the southern Atlantic archipelago, and the McMurdo Dry Valleys. The McMurdo Dry Valley populations are at the lower range of the size spectrum for the species. Streams flow for 6–10 weeks during the austral summer, when temperatures and solar radiation allow glacial ice to melt. The diatom flora of the region is characterized by species assemblages favored under harsh conditions, with naviculoid taxa as the dominant group and several major diatom groups conspicuously absent. [ABSTRACT FROM AUTHOR]

This paper investigates the developmentally programmed and plastic processes of growth in the multistemmed, deciduous shrub Vaccinium hirtum Thunb. We conducted the demographic censuses of stems and the measurements of stem growth and morphology along a natural light gradient in forest understory. With light availability from 5%–28%, the probability of sprouting new stems increased three-fold. Sprouts growing in well-lit conditions were larger than sprouts growing less light. In contrast, neither leaf area per unit aboveground biomass (LAR) nor relative growth rates of aboveground biomass (RGR) of individual stems changed significantly with light. Irrespective of light availability, LAR increased and RGR decreased with stem age. RGR approached zero in old stems > 12-years-old, and their aboveground biomass productions were mostly used to replace deciduous leaves. Our results suggest that the response of aboveground structures to increasing light availability occurs by the production of new sprouts, rather than by the increased growth of existing stems. This indicates a hierarchy of plasticities within the multistemmed structure. Age-related strong controls of stem development reflect the sprouting and multistemmed habits. This growth strategy is favorable under high-stress environments with generally low resource levels such as forest understory and with unpredictable resource pulses such as caused by canopy gap disturbances. [ABSTRACT FROM AUTHOR]

This paper presents the results of an experiment replicating traditional Interior Salish pit-cooking methods to process balsamroot (Balsamorhiza sagittata (Pursh) Nutt.), a former food staple that contains the complex carbohydrate inulin. Analysis of fresh and cooked balsamroot samples reveals that with sufficient heat, moisture, and the release of volatile organic acids, inulin is hydrolyzed during pit cooking. This process converts complex carbohydrates into simple ones, resulting in an increase of 250% in the energy provided by simple sugars. When the average energy contributions of protein, simple and complex carbohydrates are tallied, the net result is an energy gain of approximately 65% between fresh and pit-cooked balsamroot. This research demonstrates the effectiveness of ancient pit-cooking practices in transforming unpalatable and inedible root resources into sweet-tasting, highly digestible sources of carbohydrate energy and supports my assertion that this processing technology was a key component of the wild plant food production systems of Interior Salish Peoples. [ABSTRACT FROM AUTHOR]

This paper discusses local understanding of plants and habitats, based on the linguistic evidence [terms for plants and (or) habitats] gathered from ethnobotanical and ethnoecological field work conducted with several Dene Nations of the Canadian northwestern boreal forest and adjacent regions. Nations involved in the study include Gwich’in (Mackenzie Delta Region), Sahtú’otine’ (Great Bear Lake), Kaska Dena (southern Yukon), and Witsuwit’en (northwest British Columbia). Key plant-related habitats include meadow, “swamp”, forest, “willows”, and “brush”. The ethnobotanical classification of willows is explored in conjunction with the explanation of the Dene habitat concept. In local classifications, ‘willow’ is not co-extensive with the genus Salix, but includes a variety of medium to tall woody shrubs that lack either conspicuous flowers, ‘berries’, or thorns; these may include shrubby species of Salix, Alnus, Cornus, and Betula. Shoreline and alpine environments are also discussed as plant habitats. Dene use of alpine environments and resources is ancient, according to the results of recent alpine ice patch research in the Yukon region. The Human dimensions of habitat knowledge are presented. Indigenous concepts of plant taxa and of landscape associations or habitats may differ substantially from those of scientific botany and ecology, and are based in a holistic and interactive ethnoecology. [ABSTRACT FROM AUTHOR]

Ethnographic literature documents the pervasiveness of plant-management strategies, such as prescribed burning and other kinds of cultivation, among Northwest Peoples after European contact. In contrast, definitive evidence of precontact plant management has been elusive. Documenting the nature and extent of precontact plant-management strategies has relevance to historians, archaeologists, managers, conservationists, forest ecologists, and First Nations. In this paper, we summarize the various lines of evidence that have been, or could be, used to document ancient cultivation in the northwest of North America. We organize this discussion by the ecological consequences of ancient plant-management practices and their documented or potential visibility in the paleo-, neo-ecological, and archaeological records. Our review demonstrates that while finding evidence of ancient plant management can be difficult, such evidence can be found when innovative research methods are applied. Further, when various independent lines of evidence are compiled, reconstructions of past plant-management strategies are strengthened considerably. [ABSTRACT FROM AUTHOR]

In this paper, we seek to identify the genetic basis of self-incompatibility (SI) in Campanula rapunculoides L. through diallel analysis of full siblings; to characterize the growth of pollen tubes in vivo after incompatible and compatible pollination; and to determine whether the SI system is based on pistil S-RNases. Pollinations were performed among individuals from five diallel crosses and scored for both fruit set and pollen-tube growth to determine the genetic basis of SI. On a subset of these individuals with known cross-(in)compatibility relationships, additional crosses were performed and pistils collected 1, 3, 6, 12, and 24 h after pollination to assess both the percentage of pollen grains that had germinated on the stigma, and the number of pollen tubes that had grown 20%, 40% 60%, 80%, and 100% of the distance down the pistil over five time intervals. Finally, total pistillate proteins were extracted and subjected to isoelectric focusing and RNase activity staining to find evidence of a highly basic S-RNases associated with SI in the Solanaceae. We found evidence that the SI system was based on the haplotype of the male gametophyte, and was not sporophytic. Protein analyses showed that SI was not based on a pistillate S-RNase. The existence of modifiers of SI and possible polyploidy at the S-locus complicated the expression of SI in this species, and single-gene inheritance could not be determined. This represents the first published characterization of incompatibility in the family Campanulaceae. [ABSTRACT FROM AUTHOR]

The article introduces papers on the importance of tree and forest biology research in Canada, including a review of the effects of light levels on hydraulic architecture of temperate trees, an examination of leaf physiology in black cottonwood and balsam poplar and a paper on the future of boreal forest growth in line with rising atmospheric carbon dioxide levels.

The article discusses papers on ethnobotany in Canada published within this issue, including one on traditional nutritional knowledge and another on the traditional use of plants for medicine in the Arctic.

The author discusses the research works and contributions and research career of Dr. Larry Fowke, who was elected as a Fellow of the Royal Society of Canada, on cell biology in which it says that Fowke has published over 100 paper in international journals.