Lupinus Arcticus Research Articles

High Efficacy of Green Synthesized Silver Nanoparticles for Treatment of Toxoplasma Gondii Infection Through Their Immunomodulatory, Anti-Inflammatory, and Antioxidant Potency.

The present experimental survey designed to green synthesis, characterization, as well as in vitro and in vivo anti-Toxplasma gondii activity of silver nanoparticles (SLN) green synthesized by Lupinus arcticus extract. SLN were green synthesized based on the reducing by L. arcticus extract through the precipitation technique. In vitro lethal effects of SLN on T. gondii tachyzoites, infectivity rate, parasites inside of the human macrophage cells (THP-1 cells), nitric oxide (NO) triggering, and iNOS and interferon gamma (IFN-γ) expression genes were evaluated. In vivo, after establishment of toxoplasmosis in BALB/c mice via T. gondii ME49 strain, mice received SLN at 10 and 20mg/kg/day alone and combined to pyrimethamine at 5mg/kg for 14 days. SLN exhibited a spherical form with a size ranging from 25 to 90nm. The 50% inhibitory concentration (IC50) value of SLN and pyrimethamine against tachyzoites was 29.1 and 25.7µg/mL, respectively. While, the 50% cytotoxic concentration (CC50) value of SLN and pyrimethamine against THP-1 cells was 412.3µg/mL and 269.5µg/mL, respectively. SLN in combined with pyrimethamine obviously (p < 0.05) decreased the number and size of the T. gondii cysts in the infected mice. The level of NO, iNOS and IFN-γ genes was obviously (p < 0.001) upregulated. SLN obviously (p < 0.05) decreased the liver level of oxidative stress and increased the level of antioxidant factors. The findings displayed the promising beneficial effects of SLN mainly in combination with current synthetic drugs against latent T. gondii infection in mice. But we need more experiments to approve these findings, clarifying all possible mechanisms, and its efficiency in clinical phases.

Immunomodulatory, Antioxidant, and Anti-Inflammatory Activities of Green Synthesized Copper Nanoparticles for Treatment of Chronic Toxoplasma gondii Infection.

Nowadays, interest in the use of nanotechnology for medical purposes is increasing. The current experimental investigation is planned for the green synthesis, characterization, and efficacy of copper nanoparticles (CLN) against chronic Toxoplasma gondii infection. Green synthesis of CNP was performed using the Lupinus arcticus extract via the precipitation method. The effects of CNP on tachyzoites, infectivity rate, parasites inside THP-1 cells, nitric oxide (NO) triggering, iNOS, and IFN-γ expression genes were evaluated. Following toxoplasmosis in BALB/c mice via the T. gondii ME49 strain, mice received CNP at 5 and 10 mg/kg/day alone and combined with pyrimethamine (PYM) at 5 mg/kg for two weeks. CNP's in vivo effects were evaluated by analyzing the load and size of cysts, oxidant/antioxidant enzymes, and bradyzoite surface antigen 1 (BAG1) expression gene levels. CNP displayed a circular shape ranging from 10 to 85 nm. The IC50 value of CNP and PYM against tachyzoites was 37.2 and 25.7 µg/mL, respectively, whereas the CC50 value of CNP and pyrimethamine against THP-1 cells was 491.4 μg/mL and 269.5 μg/mL, respectively. The rate of infectivity and parasite load among THP-1 cells exposed to CNP was obviously reduced (p < 0.05). CNP at the doses of 5 and 10 mg/kg predominantly along with PYM evidently (p < 0.05) reduced the number and size of the T. gondii cysts in the infected mice. The levels of NO, iNOS, and IFN-γ genes were remarkably (p < 0.001) boosted compared with the cells without treatment. CNP at the doses of 10 and 20 mg/kg drastically (p < 0.05) reduced the oxidative stress markers in the infected mice, whereas CNP significantly elevated the level of antioxidant factors. CNP also revealed no toxicity in the liver and kidney at the tested doses in healthy mice. Our experimental study reported the beneficial effects of CNP principally along with existing chemical drugs against latent toxoplasmosis in mice, whereas the possible action mechanisms of CNP are controlling oxidative stress, refining antioxidant enzymes, and increasing the production of immunomodulatory cytokines with no toxicity to the function of vital organs. But, additional trials are required to confirm these results, as well as to clarify the accurate mechanisms and their toxicity.

Herbaceous plants growing in Arctic zones as potential perspective sources of valuable flavonoids

Flavonoids represent a wide group of polyphenols involved in many key processes of plant growth and its can be successfully used in medical practice. In plants that are exposed to extreme factors of various nature, the flavonoids synthesis occurs more intensively compared with plants of the same species growing under more favorable conditions. Thus, it can be assumed that it is the Arctic plants that can be important sources of flavonoids. This paper presents the results of a search for flavonoid sources among herbaceous plants growing in the Arctic zone, in particular, the Murmansk region. The total flavonoid content in ethanol extracts of 24 plant species was estimated using the reaction of complexation with aluminum chloride. It was shown that Lathyrus pratensis L., Lupinus arcticus L., Hedysarum alpinum L., Chamaenerion angustifolium L., and Polygonum weyrichii species contain the highest amounts of flavonoids.

Floral Longevity and Attraction of Arctic Lupine, Lupinus arcticus: Implications for Pollination Efficiency

Pollination by insects is a mutualistic relationship in which flowers receive pollen for reproduction while pollinators are rewarded with pollen or nectar. Floral longevity (the period an individual flower blooms) and floral attraction (the period during which pollinators are attracted to the flower, often indicated by petal colour) both play prominent roles in plant and pollinator success. This study investigated whether floral longevity and floral attraction were mediated by pollination type in arctic lupine (Lupinus arcticus S. Wats.), a common herbaceous perennial in northwestern North America. Flowers were either open to pollinators, cross-pollinated by hand, or bagged to prevent cross-pollination, and floral longevity, seed set, and flower colour were observed. Open and hand-pollinated flowers had significantly shorter floral longevities and higher percent fruit sets than bagged flowers. A colour change of the banner petal marking from white to pink occurred in some flowers and was a signal of floral attraction, as pollinators preferentially visited pre-change flowers. Pre-change flowers contained more pollen and were less likely to have been injured by herbivory than post-change flowers, yet the colour change was not related to pollination type or fruit set. Pollination-induced shortening of floral longevity is likely an adaptation to limited plant resources and pollinator visitation rates. For L. arcticus, this could be influenced by short growing seasons and low annual temperatures in the study area. In the face of climatic changes and shifting species phenologies, the mediation of floral longevity by pollinators could decrease temporal mismatch between plants and their pollinators, yet the many factors at play make this difficult to accurately predict.

Potential Contribution of Native Herbs and Biological Soil Crusts to Restoration of the Biogeochemical Nitrogen Cycle in Mining Impacted Sites in Northern Canada

The nitrogen cycle is highly sensitive to pollutants and restoration of this biogeochemical pathway is essential to ensure long-term sustainable ecosystems. Due to their ability to fix nitrogen, some native herb species and Biological Soil Crusts (BSCs) may promote plant community growth and help to establish primary successional processes. In a greenhouse trial, growth and nitrogen fixation rates of yellow mountain aven ( Dryas drummondii ), alpine sweetvetch ( Hedysarum alpinum ), field locoweed ( Oxytropis campestris ) and arctic lupine ( Lupinus arcticus ) were determined in tailings and mining impacted soils with amendments of Rhizobia and biochar. In a growth chamber trial, Pure Nostoc commune culture, Dried Nostoc spp. and BSC slurries derived from mature soil crusts were applied with and without biochar to tailings. Arctic lupine had the highest biomass and all species except yellow mountain aven showed nitrogen fixation in tailings and mining impacted soils. Nodulation and nitrogen fixation only occurred in herbs given a Rhizobia inoculum, suggesting the use of nitrogen-fixing species in northern reclamation may require microbial amendments. When used in combination with Rhizobia inoculum, biochar may promote nitrogen fixation associated with herb species. BSC slurries from mature soil crusts had significantly higher mean rates of nitrogen fixation (95μmol N m2 /hr) compared with other soil crust species (5–23μmol N m2 /hr). Biochar, Rhizobial inoculants and native nitrogen fixing species can enhance revegetation and nitrogen input in northern mining impacted substrates. However, large scale field experiments are required to identify suitable landscapes and determine how these initial nitrogen fixing species influence subsequent succession.

Plant Responses to Natural and Experimental Variations in Temperature in Alpine Tundra, Southern Yukon, Canada

Substantial climate warming is predicted for high latitude regions and may have large impacts on tundra communities. As part of the International Tundra Experiment, this study characterized plant responses to natural and experimental variations in temperature at a subarctic, alpine tundra site. Non-destructive measures of plant reproduction and growth were monitored annually for four target species (Dryas octopetala, Lupinus arcticus, Polygonum viviparum, and Salix arctica) from 1999 to 2008. Plants were exposed to 8 years of an experimental warming treatment using open-topped chambers (OTCs). Temperatures in OTCs tended to be warmer at midday but cooler at night, with little net daily warming. OTCs had relatively little effect on plant responses, except for positive effects on reproductive characteristics of D. octopetala and P. viviparum. All target species except L. arcticus showed significant annual variations in vegetative and reproductive characteristics. Non-destructive measures used to monitor plant performance were significantly related to actual growth and reproductive output in most cases. Plant community composition did not show experimental effects nor were there consistent trends in composition over the 10 years of the study. Results of the study highlight individualistic species responses and the resilience of the plant community to observed temperature variations at this site.

Radiocarbon dates reveal that Lupinus arcticus plants were grown from modern not Pleistocene seeds

Radiocarbon dates reveal that <i>Lupinus arcticus</i> plants were grown from modern not Pleistocene seeds

Summer diet selection of snowshoe hares: a test of nutritional hypotheses

We examined summer diet selection by snowshoe hares in the southwestern Yukon, Canada, and attempted to explain how plant qualities such as nutritional content (protein, energy, fiber, water) and defensive compounds affect hare food choice. Male hares were placed in enclosures in natural vegetation areas dominated by shrubs and in both open and closed spruce forests. Each site contained a variety of herbaceous plant species. After 24 h, hares were sacrificed, their stomachs collected, and the contents removed and analyzed. Of the 30 plant species recorded in the enclosures only 10 were identified in the stomach contents of the hares. The summer diet is composed predominantly of five plant species; Lupinus arcticus, Salix spp. Shepherdia canadensis, Betula glandulosa and Festuca altaica. The selection of these species changes between sampling times. Protein, energy and water contents were highest in leaf tissues of most species early in the season, and most species had an increase in fiber through the summer. Protein content consistently explains the largest amount of variation in diet selection, although protein selection is modified by extremely high concentrations of defence compounds. It is likely that hares are not protein limited and are selecting for other plant characteristics correlated with protein content such as energy content. It is significant that hares continue to ingest heavily defended species (e.g. Shepherdia canadensis, B. glandulosa and L. arcticus) when many less defended plants are available to be eaten (e.g. F. altaica, Epilobium latifolium and Anemone parviflora). Our results support the idea that hares are selecting dietary items on the basis of energy content. No single plant species can satisfy all of the hares’ nutritional requirements and the selection patterns may reflect the need to balance many conflicting plant qualities.

Range Extension of the Northern Long-eared Bat (Myotis septentrionalis) in the Yukon

DEARING MD. 1996. Disparate determinants of summer and winter diet selection of a generalist herbivore, Ochotona princeps. Oecologia 108:467–478. DEARING MD. 1997. The manipulation of plant toxins by a food-hoarding herbivore, Ochotona princeps. Ecology 78:774–781. DIXON J. 1919. Notes on the natural history of the bushy-tailed wood rats of California. University of California Publications in Zoology 21:49–74. ESCHERICH PC. 1981. Social biology of the bushytailed woodrat, Neotoma cinerea. University of California Publications in Zoology 110:1–132. FINLEY JR. RB. 1958. The wood rats of Colorado: Distribution and ecology. University of Kansas Publications Museum of Natural History 10:213–552. HICKLING GJ, MILLAR JS, MOSES RA. 1991. Reproduction and nutrient reserves of bushy-tailed wood rats (Neotoma cinerea). Canadian Journal of Zoology 69:3088–3092. MACKINNON A, POJAR J, COUPE R. 1992. Plants of northern British Columbia. Vancouver, BC: Lone Pine Publications. 352 p. PRATT VE. 1991. Wildflowers along the Alaska Highway. Anchorage, AK: Alaskakrafts, Inc. 230 p. SHARAM GJ, TURKINGTON R. 2005. Diurnal cycles of sparteine production in Lupinus arcticus. Canadian Journal of Botany 83:1345–1348. SMITH CC, REICHMAN OJ. 1984. The evolution of food caching by birds and mammals. Annual Review of Ecology and Systematics 15:329–351. SMITH FA. 1997. Neotoma cinerea. Mammalian Species 564:1–8. SORENSEN JS, DEARING MD. 2003. Elimination of plant toxins by herbivorous woodrats: revisiting an explanation for dietary specialization in mammalian herbivores. Oecologia 134:88–94. TOPPING MG, MILLAR JS. 1996. Foraging movements of female bushy-tailed woodrats (Neotoma cinerea). Canadian Journal of Zoology 74:798–801.

Diurnal cycle of sparteine production in Lupinus arcticus

Sparteine is a neurological toxin found in arctic lupine ( Lupinus arcticus S. Wats.) and is probably used as a defensive chemical to deter herbivory, particularly by snowshoe hares ( Lepus americanus Erxleben). Lupine leaves were collected in southwestern Yukon at 2 h intervals for 2 consecutive days at the peak of the growing season (24–25 June), and their sparteine was extracted and compared with a standard using gas chromatography. A significant daily cycle of sparteine in leaf material was observed, with maximum concentrations occurring during the night and minimum during the afternoon. This may be a temporally optimal response to higher levels of hare herbivory that occur at night.

Do Nutrient Availability and Competition Limit Plant Growth of Herbaceous Species in the Boreal Forest Understory?

An experiment was conducted to investigate whether nutrient availability and competition limit aboveground growth of five herbaceous species in the boreal forest understory. The experiment involved adding fertilizer and removing neighbors of selected target individuals of five different species. Aboveground biomass and leaf number were measured as the response variables, and treatment effects were tested using ANOVA and ANCOVA. The five species showed variable responses to fertilizer addition with Achillea millefolium, Festuca altaica, and Mertensia paniculata showing significant increases. Lupinus arcticus had no response and there was a strong negative effect on survival of Anemone parviflora. Achillea was the only species that showed some growth limitation due to neighboring individuals for both biomass and leaf number; other species showed no response.

The effects of fertilization and herbivory on the herbaceous vegetation of the boreal forest in north‐western Canada: a 10‐year study

Summary1 The influence of fertilizer addition and mammalian herbivore exclosures (a 2 × 2 factorial design, with four replicates at each of two sites) on the cover, species composition and diversity of the understorey vegetation of the boreal forest in the south‐western Yukon, Canada, were investigated from 1990 to 1999. This was done to test whether vegetation composition was controlled by resource level alone (bottom‐up control), herbivory alone (top‐down control), or by both (interactive control).2 The density of the major herbivore, the snowshoe hare, varied 25‐fold, declining from 148 km−2in 1990 to 8 km−2in 1994, and increasing to a second peak of 198 km−2in 1998.3 In control plots most species were remarkably constant in percent cover. After 10 years, most of the major species showed significant responses to fertilizer with four species increasing (Festuca altaica,Mertensia paniculata,Epilobium angustifolium, andAchillea millefolium), and three declining (Linnaea borealis,Lupinus arcticus,Arctostaphylos uva‐ursi). Some species took up to 5 years before a response was detected.4 Fertilization caused (i) a decline in the number of species, and species evenness in the community, (ii) a reduction in the proportion of woody species, and (iii) an increase in herbaceous dicotyledons and grasses.5 The exclusion of herbivores had virtually no impact on the abundance of the vegetation or on species diversity, except in 1990–92 during a decline from a peak of 148 hares km−2to 29 hares km−2.6 These results suggest that the percentage cover and composition of herbaceous vegetation in the boreal forest are determined almost exclusively by the productivity of the site (bottom‐up control) and that the activities of mammalian herbivores may be important only during peaks in hare population densities (interactive control).7 Results were both species‐specific and time‐dependent, suggesting that long‐term studies are needed to discriminate between long‐term responses to treatments and transient phenomena.

The influence of herbivores and neighboring plants on risk of browsing: a case study using arctic lupine (Lupinus arcticus) and arctic ground squirrels (Spermophilus parryii plesius)

We examined how herbivore distribution and density, neighboring plant density and species composition, and individual plant morphology all influence the risk that individual arctic lupines (Lupinus arcticus) will be browsed by arctic ground squirrels (Spermophilus parryii plesius). Risk of being browsed was significantly influenced by the number of resident ground squirrels but not by overall squirrel density at a site. As the leaf density of neighboring conspecifics increased, risk of browsing to an individual lupine decreased except when palatable neighbors were also present. The presence of other palatable species increased the risk of browsing. Risk was highest when both lupine and other palatable neighbors were present. The presence of unpalatable neighbors reduced the risk of browsing of individual lupines. We discuss these results in the context of three hypotheses: (1) attractant decoy, (2) resource concentration, and (3) repellent plant. No single hypothesis accounts for our observations, but an interaction between herbivores, neighbors, and individual lupine morphology determined risk of browsing.

Population dynamics response of Lupinus arcticus to fertilization, clipping, and neighbour removal in the understory of the boreal forest

A demographic study was conducted on field populations of Lupinus arcticus S. Wats. growing in the understory of a white spruce dominated forest, near Kluane Lake, Yukon. The relative effects of soil fertility level, neighbours, and herbivory were assessed using a factorial experiment of ± fertilizer (N-P-K), ± neighbour removal, and ± clipping. We monitored the dynamics of leaves and collected data on reproduction, survival, and size for two growing seasons. Fertilizing increased the incidence of disease on leaves and reduced reproductive efficiency. Clipping reduced leaf cohort survivorship, total leaf density, and the incidence of disease on leaves. Removing neighbours increased the percent cover of L. arcticus and decreased total leaf mortality. Treatments had no effect on the survival of leaves in early cohorts. Although there were some significant responses to treatments, the overall tendency was a lack of response, especially pertaining to leaf population dynamics. This low response to the treatments imposed is consistent with the argument that plants growing in low productivity, infrequently disturbed habitats should show little response to short-term changes in local environmental conditions. The results are also consistent with suggestions that plants in moderately stressed habitats should be more adapted to withstand grazing than competition.Key words: boreal forest, competition, demography, fertilization, population dynamics, Lupinus arcticus.

Population dynamics response of &lt;i&gt;Lupinus arcticus &lt;/i&gt;to fertilization, clipping, and neighbour removal in the understory of the boreal forest

A demographic study was conducted on field populations of Lupinus arcticus S. Wats. growing in the understory of a white spruce dominated forest, near Kluane Lake, Yukon. The relative effects of soil fertility level, neighbours, and herbivory were assessed using a factorial experiment of ± fertilizer (N-P-K), ± neighbour removal, and ± clipping. We monitored the dynamics of leaves and collected data on reproduction, survival, and size for two growing seasons. Fertilizing increased the incidence of disease on leaves and reduced reproductive efficiency. Clipping reduced leaf cohort survivorship, total leaf density, and the incidence of disease on leaves. Removing neighbours increased the percent cover of L. arcticus and decreased total leaf mortality. Treatments had no effect on the survival of leaves in early cohorts. Although there were some significant responses to treatments, the overall tendency was a lack of response, especially pertaining to leaf population dynamics. This low response to the treatmen...

Wildflower Seed Mixes for Alaska

The germination, establishment, survival, and public preference of four wild-flower seed mixes were evaluated in relation to irrigation and seasonal sowing date. The mixes included two commercial nonindigenous wildflower mixes, a commercial mix with indigenous and nonindigenous wildflowers, and an experimental mix composed exclusively of Alaska native wildflowers. The two latter mixes were sown with and without `Tundra' glaucous bluegrass (Poa glauca). The two nonindigenous mixes exhibited the greatest seedling establishment during the first season. Fall sowing and irrigation during seed germination significantly increased species establishment for all mixes. In the second season, 11 nonindigenous species did not reappear, whereas all of the indigenous species reappeared. The experimental mix had the greatest species richness of the six mixes in the second season. The addition of grass to the mixes did not significantly affect wildflower species richness in either the first or second season. Survey respondents preferred the nonindigenous wildflower mixes to those containing Alaska native wildflowers because of a greater mix of colors that appeared earlier in the first season than the other mixes. Alaska native species recommended for wildflower mixes include Polemonium acutiflorum, Lupinus arcticus, Hedysarum mackenzii, Arnica alpina, and Aster sibiricus.

Use of winter feeding craters by snowshoe hares

Snowshoe hares (Lepus americanus) in the southwest Yukon foraged in winter on ground vegetation by digging feeding craters in snow. Hares utilized at least three species: Dryas drummondii, Hedysarum mackenzii, and Lupinus arcticus. Hares dug feeding craters to reach these plants in snow up to 36 cm deep, and the area of these craters ranged from 140 to 2600 cm2. I recorded few craters after midwinter when snow depths reached 40 cm; the few craters dug at this time were in areas of shallow snow either beneath trees or in windswept areas. When hares had stopped digging craters, I established 11 small plots (1 × 1 or 1 × 2 m) where I removed snow to ground level. Hares moved in and used these areas to feed on D. drummondii and L. arcticus. I conclude that the vegetation was suitable for hares and speculate that hares stopped digging feeding craters because snow depth or snow density made it energetically uneconomical. The food value of these plants and their importance in the winter diet of hares needs further study.

Lupine Aphid, Macrosiphum albifrons (Homoptera: Aphididae): Distribution and Hymenopterous Parasites in British Columbia

The lupine aphid, Macrosiphum albifrons Essig, occurs throughout southwestern British Columbia on Lupinus arcticus S. Wats. and L. polyphyllus Lindl., and less frequently on L. sericeus Pursch. It is parasitized by four species of Aphidiidae: Aphidius lupini Liu, Ephedrus californicus Baker, and two unidentified species of Praon. Percentage of parasitism varied seasonally and between collecting sites. A. lupini was the most common and widespread parasite; it killed an average of 5.2, 7.6, and 9.0% of secondo-, third- and fourth-instar aphids, respectively, over the season as a whole. A fungal pathogen, Entomophthora sp., caused ca. 60% mortality among third- and fourth-instar aphids during rainy periods in late spring and late summer. A. lupini is considered as a potential agent for biological control of the lupine aphid in England.

Evidence for Longevity of Seeds and Microorganisms in Permafrost

The problem of whether seeds and microorganisms are able to remain viable in permanently frozen ground during a very long span of years was recently considered by Porsild et al. who germinated Lupinus arcticus seeds from fossil rodent burrows in permanently frozen silt deposited in a placer mining area in the Yukon Territory. Based on the geology of the locality, Porsild et al. estimated the age of the seeds to be at least 10,000 years. Moreover, in that and in previous papers Porsild suggests that seeds of Rorippa barbareaefolia, Descurainia sophioides, and Senecio congestus may be able to survive in permanently frozen silt as these species apparently are restricted to freshly disturbed soil within the placer mining districts. Discussing in general the problems of dating viable seeds in old deposits Godwin questions the dating of the Lupinus arcticus seeds because of the indirect method applied. In view of these studies and the investigations made by Odum on the presence and age of viable seeds in Danish soils, Ester Creek placer mine west of Fairbanks, Alaska, was visited 16 to 19 July 1968. Some observations on the vegetation on the exposed silt and disturbed soil were made and soil samples were taken for further examination .... The contents of microorganisms in the soil samples were examined by using the dilution plate technique: 10 g of each sample were mixed with 90 ml of sterile water and placed on a shaking table for 20 minutes. Serial dilutions were made, and 0.1 ml of each of 10**-1, 10**-2, 10**-3 and 10**-4 suspensions were plated on Bengal Rose-, Sabouraud-, Cook-, and V-8-agar. Besides 1 ml of each suspension was added to test tubes with NIB. After one week of incubation at 4°C, 24°C, and 37°C the colonies were counted and the different strains isolated on slants with V-8-agar. The sample from the top soil showed c 10**3 fungi per g soil at 24° C, representing the following genera, known from similar localities: Cladosporium herbarum, Mortierella sp., Mucor circinelloides, Penicillium spp., Trichoderma viride, and unidentified, sterile imperfects and phycomycetes. ... Only a few investigations have been carried out to find living microorganisms in permanently frozen soil, and generally only the upper layers have been studied, because of the difficulties of sampling through permafrost. However Becker and Volkmannlo recovered 8 bacteria at 20 to 60 feet below the surface in permanently frozen soil near Fairbanks. Boyd and Boyd also studied permafrost soils from Barrow, Alaska, near Bison Lagoon, and found living bacteria at 8 to 15 feet. The distribution of Descurainia sophioides within the placer mine area and its extremely high frequency on the exposed muck does strongly support Porsild's theory. However, the fact that the seeds of the species are lacking in the investigated samples may lead to the alternative possibility that the ecology of the species is rather specific. Which factor or combination of factors is responsible for the germination and growth of the species on that particular substratum, ... cannot be determined without field experiments at the locality and further analyses; the high water content of the silt may appear to be a factor of importance. The investigation does not prove that viable seeds of Descurainia sophioides, Rorippa barbareaefolia, Senecio congestus or any other species are not present in permanently frozen soil; the negative result of the investigation, however, indicates that on this locality it is not very likely that they are present. ...

Lupinus arcticus Wats. Grown from Seeds of Pleistocene Age

Seeds of the arctic tundra lupine (Lupinus arcticus) at least 10,000 years old were found in lemming burrows deeply buried in permanently frozen silt of Pleistocene age in unglaciated central Yukon. They readily germinated in the laboratory and have since grown into normal, healthy plants.