Symplocarpus Foetidus Research Articles

Skunk Cabbage (Symplocarpus foetidus) Coverage Reduction in a Wetland that is Habitat for the Bog Turtle (Glyptemys muhlenbergii)

Skunk Cabbage (Symplocarpus foetidus) Coverage Reduction in a Wetland that is Habitat for the Bog Turtle (Glyptemys muhlenbergii)

Floral scent of eastern skunk cabbage (Symplocarpus foetidus: Araceae)

Symplocarpus foetidus (L.) Salisb. (eastern skunk cabbage) occurs across a broad geographic range of northeastern North America, blooming in winter between December and March. The inflorescences are well-known for their thermogenic and thermoregulatory metabolic capabilities. The perceptual qualities of their fetid floral aroma have been described widely in the literature, but to date the floral volatile composition remained largely unknown. Here we present a detailed study of the floral scent produced by S. foetidus collected from intact female- and male-stage inflorescences and from dissected floral parts. Our results show a large range of biosynthetically diverse volatiles including nitrogen- and sulfur-containing compounds, monoterpenes, benzenoids, and aliphatic esters and alcohols. We document high inter-individual variation with some organ-specific volatile trends but no clear strong variation based on sexual stage. Multivariate data analysis revealed two distinct chemotypes from our study populations that are not defined by sexual stage or population origin. The chemotype differences may explain the bimodal perceptual descriptions in earlier work which vary between highly unpleasant/fetid and pleasant/apple-like. We discuss the results in ecological contexts including potential for floral mimicry, taking into account existing pollination studies for the species. We also discuss the results in evolutionary contexts, comparing our scent data to published scent data from the close sister species Symplocarpus renifolius. Future work should more closely examine the chemotype occurrence and frequency within these and other populations, and the impact these chemotypes may have on pollinator attraction and reproductive success.

Eastern skunk cabbage (Symplocarpus foetidus), a common native wetland plant, shows reduced size and seedling abundance near invasive Japanese knotweed (Reynoutria japonica) 1

Nonnative plants may shift community composition and reduce diversity through competition with native neighbors, or invasion patterns may reflect edaphic gradients that create suitable habitat for colonization. We tested the impacts of invasive Reynoutria japonica (Japanese knotweed) on performance of a co-occurring native plant, Symplocarpus foetidus (eastern skunk cabbage), to determine if invasion has potential to change community composition by altering population-level processes. We tested two hypotheses: (1) Reynoutria japonica invasion is correlated with reduced population performance in S. foetidus; (2) Reynoutria japonica invasion is correlated with environmental variation, and contrasting habitat preferences allow R. japonica and S. foetidus to coexist. Sampling took place in an urban riparian site in Pittsburgh, PA, USA. Data were collected from 26 1-m2 plots with R. japonica present (n = 13) or absent (n = 13). We recorded pH, texture, and moisture. Size and flowering of all S. foetidus individuals and R. japonica cover and abundance were recorded in each plot. Symplocarpus foetidus size was significantly reduced in invaded plots, and both size and seedling abundance were significantly negatively associated with R. japonica cover. Abundance was negatively associated with percent clay and positively associated with soil moisture; seedling abundance was also predicted by lower soil pH. In contrast, R. japonica was most abundant and had highest cover with high pH and lower percent sand. Flowering of S. foetidus did not differ significantly between invaded and uninvaded plots. We conclude that R. japonica invasion both suppresses S. foetidus and correlates with environmental heterogeneity. Reduced performance of S. foetidus in invaded plots suggests competitive suppression. While R. japonica negatively impacted S. foetidus, distinct microhabitat preferences may allow them to co-occur.

Impacts of Herbivory on Photosynthesis of Four Common Wisconsin Plant Species

Overcompensation to herbivory is prevalent among plant species. However, we do not yet fully understand why plant species vary in their compensatory abilities. It is highly likely that overcompensation is determined by the ability of plants to elevate photosynthesis in response to herbivory, which is dictated by evolutionary exposure to grazing. Here, we tested the hypothesis that photosynthetic overcompensation should be predictable based on plant life form by simulating herbivore damage on four plant species: two common range grasses with long evolutionary exposure to grazing (Andropogon gerardii, Bouteloua curtipendula) and two common understory forbs that are resistant to, and therefore experience little, grazing (Alliaria petiolata, Symplocarpus foetidus). We measured leaf-level gas exchange in a high-resolution time series that extended throughout the growing season. We found no evidence of photosynthetic compensation for three of the four plant species. Interestingly, only A. petiolata, a highly invasive species, demonstrated increased photosynthesis and stomatal conductance following clipping. Further, the effects were short-lived, as both photosynthesis and stomatal conductance returned to baseline levels within 24 h. Our results suggest that elevated photosynthesis to herbivory might not be a general mechanism by which plants either resist or tolerate herbivory.

Pollination ecology of Symplocarpus foetidus (Araceae) in a seasonally flooded bog in Québec, Canada

ABSTRACT The pollination ecology of Symplocarpus foetidus (L.) W. Salisbury was studied in a seasonally forested flooded bog in Québec (Canada) in 2008 and 2009. The protogynous anthesis duration ranged from 15 to 20 days with, chronologically, a female phase of about 5 days, a bisexual phase of 2 days, and a male phase of 9 days. The spadix temperature differences with ambient air were higher during the female phase (mean: 13.6°C) than during the bisexual and male phases (mean: 4.5°C). The air inside the floral chamber was warmed by the heating spadix, particularly during the female phase (~6°C warmer than ambient air). High temperatures were maintained through nighttime during the female phase, whereas they occurred only during the daytime during the bisexual and male phases. The average natural fruit and seed sets were relatively low (18.2% and 14%), and the fruit set varied between years (13% in 2008 vs. 31% in 2009). Since spontaneous self-pollination is a rare reproductive event, sexual reproduction in Symplocarpus foetidus relies mainly on insect cross-pollination. Pollination is probably generalist considering the large variety of Coleoptera and Diptera families attracted to the plant, such as Chironomidae, Sphaeroceridae, Mycetophilidae, Phoridae, Drosophilidae, Chloropidae, and Anthomyiidae. Since many different insect types visit the inflorescences, it is unclear whether this pollination system is a deceptive interaction (its unpleasant floral scent is typical of other deceptive Araceae), a breeding site mutualism (developing larvae have been observed on the inflorescences), or a combination of the two.

Quantification of aerenchyma lacunae in Symplocarpus foetidus to provide air to roots

Swamps, wetlands, flooded crop lands, and tidal zones occur a significant area of the earth's surface. For these places, plant roots survive in anoxic substrates. Plants of Symplocarpus foetidus are well suited for anoxic substrates, since they have aerenchyma tissues (lacunae) for air movement from leaves to roots. Air in leaves is pressurized and thus moves down petioles to provide oxygen to rhizomes and roots, in the anoxic substrates. The objective of this study is to quantify lacunae in tissues in order to demonstrate that lacunae in these tissues are well scaled to move air effectively. Lacunae comprise about 68% of all leaf volume. The total areas of all lacunae within lamina were about 500 times larger than the total area of all lacunae areas of petioles. Lacunae in petioles comprised 51% of petiole cross-sectional areas. In turn, lacunal areas in rhizomes and roots were about 30% of lacunal areas in petioles, indicating that air may pass easily from petioles to rhizomes, and then to roots. Individual lacunal areas varied among the tissues. For leaves, petioles, and rhizomes individual lacunae areas were 0.04–0.069 mm2, 0.011–0.069 mm2, and 0.037–0.121 mm2, respectively. In contrast, mean individual lacunal areas were smaller in root cross sections (0.0001–0.0064 mm2). Overall, leaves and petioles provide a large network for air flow but airflow is more restricted in rhizomes and roots. To our knowledge, this is the first study to document aerenchyma characteristics, numbers of lacunae and areas of individual lacunae in many tissues.

Assessing Dynamic Soil Properties in Southern New England Forests within an Ecological Site Framework

Core Ideas Coniferous and deciduous forests are two common states within a glaciofluvial upland ecological site. Upland soils with contrasting particle size showed similar ecological potential. Poorly drained and very poorly drained riparian ecosystems should be considered separate ecological sites. Ecological sites are a framework for documenting ecosystem conditions within a region but few have been developed for forested ecosystems. We developed ecological site concepts for southern New England glaciated forested upland and riparian benchmark soils with contrasting inherent properties. Within upland and riparian soils, we quantified the resistance or resilience of dynamic soil properties following specific management or disturbance. Although the upland soils had contrasting particle size classes, the vegetation composition, tree productivity, and soil organic C (SOC) pools were similar, suggesting that these soils have similar ecological potential. Coniferous and deciduous upland sites showed minimal differences. Selective harvest of 50% of overstory trees in the uplands decreased C addition from litter by 28% (p = 0.036) but did not significantly impact O horizon thickness or SOC contents, suggesting that C pools in these soils are resilient to selective harvesting. Although poorly and very poorly drained riparian soils had similar stands of Acer rubrum L., very poorly drained soils had larger SOC pools and thicker O horizons, and Carex stricta Lam. and Symplocarpus foetidus (L.) Salisb. ex W.P.C.Barton dominated the understory. These differences suggest these riparian soils should be considered separate ecological sites. Simulated N enrichment of riparian soils significantly (p = 0.006) increased root biomass but not CO2 respiration. Over time, N additions may increase C pools in riparian soils. Our studies suggest that ecological site concepts can be applied in southern New England forest ecosystems to establish a framework for understanding plant and soil responses to disturbance or management.

Phylogeography and Ecological Niche Modeling Reveal Reduced Genetic Diversity and Colonization Patterns of Skunk Cabbage (Symplocarpus foetidus; Araceae) From Glacial Refugia in Eastern North America.

Alternating glacial and interglacial periods during the Quaternary have dramatically affected the distribution and population genetic structure of plant and animal species throughout the northern hemisphere. Surprisingly, little is known about the post-glacial recolonization history of wetland herbaceous perennials that are widely distributed in the understory of deciduous or mixed deciduous-evergreen forests in eastern North America. In this study, we investigated infraspecific variation among 32 populations of skunk cabbage, Symplocarpus foetidus, to test the hypothesis that the extant species diversity of skunk cabbage is the result of a post-glacial range expansion from southern refugia during the Quaternary Ice Age. A total of 4041 base pairs (bp) of the chloroplast intergenic spacer region (cpDNA) was sequenced from 485 individuals sampled from glaciated (18 populations, 275 individuals) and unglaciated (14 populations, 210 individuals) regions east and west of the Appalachian Mountains. Haplotype number, haplotype diversity, and nucleotide diversity were calculated, and genetic variation within and among populations was assessed by analysis of molecular variance (AMOVA). The geographic pattern of genetic differentiation was further investigated with a spatial analysis of molecular variance (SAMOVA). A total of eight haplotypes and three genetic groups (SAMOVA) were recovered and a much higher haplotype number (eight haplotypes) and haplotype diversity (0.7425) was observed in unglaciated compared to glaciated populations (five haplotypes, haplotype diversity = 0.6099). All haplotypes found in glaciated regions represented a subset of haplotypes found in unglaciated regions. Haplotypes of S. foetidus likely diverged during the Tertiary (mid-Miocene and late Pliocene), predating the last glacial maximum (LGM). Predictions based on ecological niche modeling (ENM) suggested that there was considerably less suitable habitat for skunk cabbage during the LGM, and the habitat range was further south compared to the current distribution. Reduced variation and a subset of haplotypes in glaciated regions suggest a founder effect associated with range expansion via long-distance seed dispersal. Our results do not support the “Driftless Area” scenario for the northern refugium, rather the data suggest a “Northeastern” refugium near the southernmost extent of the LGM.

Herbaceous Vascular Flora Of Forested Seep Wetlands In Winneshiek County, Iowa, USA

Forested seep wetlands dominated by skunk cabbage (Symplocarpus foetidus) occur frequently in the Canoe Creek watershed of the Upper Iowa River, but this type of wetland has not been described systematically in the upper Midwest. The goal of this study is to document the herbaceous plant flora of five seeps. Although individual seeps are small (200-500 m2), they provide habitat for a high number of plant species. Five seeps with total area less than 0.2 ha supported more than 120 native vascular herbaceous taxa, 20 of which have a coefficient of conservatism (C-value) of 7 or higher and 23 that are obligate wetland species. Several species that were common in these habitats 100 years ago appear to have been locally extirpated or have become uncommon in the region, including Gentianopsis crinita, Cirsium muticum, Eupatorium altissimum, Chelone glabra, and Micranthes pensylvanica. Today, these plant communities are threatened by invasive plant species, high levels of deer herbivory, and destruction by human activities. We hope that by documenting their current species composition we can inspire protection of these wetlands and provide a baseline for monitoring future changes.

Chemical Composition and Aroma Evaluation of Essential Oils from Skunk Cabbage (Symplocarpus foetidus).

Two sample preparation methods, namely hydrodistillation (HD) and solvent-assisted flavor evaporation (SAFE), have been used to investigate the essential oils of the aerial parts (leaves and stems) of Symplocarpus foetidus, a plant with a characteristic odor, by gas chromatography mass spectrometry (GC-MS). Characteristic aroma-active compounds in the oils were detected by GC-Olfactometry (GC-O) and aroma extract dilution analysis (AEDA). From the HD method, the main compounds in the oil were found to be p-vinyl-guaiacol (15.5%), 2-pentyl-furan (13.4%), and (Z)-ligustilide (9.5%). From the SAFE method, the main compounds were 2-butoxy-ethanol (49.6%), ethyl-pentanoate (4.5%), and mesitylene (4.0%). In HD oil, the most intense aroma-active compounds were 2-pentyl-furan (flavor dilution factor (FD) = 32, odor activity value (OAV) = 57), p-vinyl-guaiacol (FD = 16, OAV = 41), and dimethyl disulfide (FD = 16, OAV = 41). In SAFE oil, the main aroma-active compounds were 2-butoxy ethanol (FD = 32, OAV = 16), and 2-methoxy thiazole (FD = 32, OAV = 25).

Surface micro/nanotopography, wetting properties and the potential for biomimetic icephobicity of skunk cabbage Symplocarpus foetidus.

Lotus (Nelumbo nucifera) is known for its two remarkable properties: superhydrophobicity and thermogenesis; however, the relationship between these two properties remains obscure. Most botanists agree that thermogenesis helps to attract pollinators, while non-wetting helps to catch pollinators and prevents contamination. Here we investigate the surface micro- and nanotopography and wetting properties of eastern skunk cabbage (Symplocarpus foetidus), another thermogenic plant, which is known for its ability to melt snow. The skunk cabbage leaves are hydrophobic but not superhydrophobic, and they have high contact angle hysteresis (similar to the rose petal effect). We develop a heat transfer model to relate icephobicity with heat transfer and discuss the biomimetic potential that both thermogenic and superhydrophobic plants may have for icephobicity in soft materials.

Presence of indicator plant species as a predictor of wetland vegetation integrity: a statistical approach

We fit regression and classification tree models to vegetation data collected from Ohio (USA) wetlands to determine (1) which species best predict Ohio vegetation index of biotic integrity (OVIBI) score and (2) which species best predict high-quality wetlands (OVIBI score >75). The simplest regression tree model predicted OVIBI score based on the occurrence of three plant species: skunk-cabbage (Symplocarpus foetidus), cinnamon fern (Osmunda cinnamomea), and swamp rose (Rosa palustris). The lowest OVIBI scores were best predicted by the absence of the selected plant species rather than by the presence of other species. The simplest classification tree model predicted high-quality wetlands based on the occurrence of two plant species: skunk-cabbage and marsh-fern (Thelypteris palustris). The overall misclassification rate from this tree was 13 %. Again, low-quality wetlands were better predicted than high-quality wetlands by the absence of selected species rather than the presence of other species using the classification tree model. Our results suggest that a species’ wetland status classification and coefficient of conservatism are of little use in predicting wetland quality. A simple, statistically derived species checklist such as the one created in this study could be used by field biologists to quickly and efficiently identify wetland sites likely to be regulated as high-quality, and requiring more intensive field assessments. Alternatively, it can be used for advanced determinations of low-quality wetlands. Agencies can save considerable money by screening wetlands for the presence/absence of such “indicator” species before issuing permits.

Antimycobacterial screening of traditional medicinal plants using the microplate resazurin assay

Multidrug-resistant Mycobacterium tuberculosis strains have rapidly become a global health concern. North American First Nations communities have used traditional medicines for generations to treat many pulmonary infections. In this study, we evaluated the antimycobacterial activity of 5 medicinal plants traditionally used as general therapeutics for pulmonary illnesses and specifically as treatments for tuberculosis. Aqueous extracts of Aralia nudicaulis, Symplocarpus foetidus, Heracleum maximum, Juniperus communis, and Acorus calamus were screened for antimycobacterial activity against Bacillus Calmette-Guérin, Mycobacterium avium, and M. tuberculosis H37Ra using the colorimetric microplate resazurin assay. Extracts of Acorus calamus and H. maximum root demonstrated significant antimycobacterial activity comparable to that of the rifampin control (2 microg/mL). Evaluation of the cytotoxicity of these 2 extracts using the MTT assay also showed that the extracts were less toxic to 3 human cell lines than was the DMSO positive control. This study demonstrates that aqueous extracts of the roots of H. maximum and Acorus calamus possess strong in vitro antimycobacterial activity, validates traditional knowledge, and provides potential for the development of urgently needed novel antituberculous therapeutics.

Palynological insights of the eastern Asian and eastern North American disjunct genus Symplocarpus (Araceae)

Symplocarpus L. (Araceae) is a disjunct genus including S. foetidus (L.) Nutt. var. latissimus (Makino) S. Hara, S. nipponicus Makino, and S. nabekuraensis Otsuka & K. Inoue in temperate eastern Asia; S. egorovii N. S. Pavlova & V. A. Nechaev in the Russian far east; and S. foetidus (L.) Nutt. in temperate northeastern North America. For the first time, pollen morphology of Symplocarpus was investigated by light and scanning electron microscopes. Symplocarpus foetidus var. latissimus and S. foetidus had reticulate surfaces and rounded (obtuse), long, equatorial axis tips, whereas S. nipponicus had microreticulate surfaces and acute tips. Symplocarpus foetidus in North America had larger pollen grains than S. foetidus var. latissimus in eastern Asia. Thus, based on pollen characteristics, S. foetidus var. latissimus is more closely related to S. foetidus than to S. nipponicus. Other lines of evidence, such as molecular phylogenetic studies and phenology, support the phylogenetic relationships among these species proposed in this study. The slightly modified acetolysis procedure conducted in this paper is a promising application to study weak exine or exineless pollen grains.

Modeling of thermoregulation in the skunk cabbage in relation to meteorological factors

A model is proposed to calculate the spadix temperature of the skunk cabbage Symplocarpus foetidus which regulates its internal temperature at around 20 °C during the female stage even when the ambient air temperature drops below freezing. The model is based on energy balance of the spadix under field conditions. The input data are standard meteorological data and spadix parameters. The model output was compared with experimental data collected under different climate conditions. The agreement between observed and calculated spadix temperatures was fairly good.

Algorithm for Temperature Control in the Skunk Cabbage, Symplocarpus Foetidus

ABSTRACTThis paper presents a temperature control algorithm for the spadix of the skunk cabbage Symplocarpus foetidus, a plant which holds its spadix temperature nearly constant. We derive the control algorithm from a proposed thermoregulation model of the spadix of S. foetidus. In addition, we investigate the control algorithm of S. foetidus for general industrial applications from a control engineering perspective by running simulations and applying it to actual equipment. The temperature control algorithm responds to the rate of change of the controlled variable over time and adjusts the output of the controller as required to minimize the rate of change. The control algorithm of the spadix of S. foetidus is robust to perturbations in the controlled object, and the control algorithm incorporated into a microprocessor successfully controls the performance of actual equipment.

Modeling of the thermoregulation system in the skunk cabbage:Symplocarpus foetidus

This paper presents a model of the thermoregulation system of the spadix of skunk cabbage Symplocarpus foetidus which regulates its internal temperature at around 20 degrees C during flowering even when the ambient air temperature drops below freezing. From the temperature responses of the spadix to changing ambient air temperature, we assumed that the thermoregulation system of the spadix is probably one of negative feedback control. The feedback signals are based on the rate of temperature change of the spadix over time. A signal is factored into the biochemical energy generator, and becomes biochemical energy, some of which becomes heat. Comparing our proposed model temperature responses and those of the living spadix, we found good agreement. In the process of engineering the model, the existence of two regulatory pathways in the thermoregulation system was simulated, and our proposed model appears to provide the necessary elements to explain the fundamental mechanism of the thermoregulation system of S. foetidus.

Functional analysis of skunk cabbage SfUCPB, a unique uncoupling protein lacking the fifth transmembrane domain, in yeast cells

Skunk cabbage, Symplocarpus foetidus, expresses two uncoupling proteins (UCPs), termed SfUCPA and SfUCPB, in the thermogenic organ spadix. SfUCPB exhibits unique structural features characterized by the absence of the putative fifth transmembrane domain (TM5) observed in SfUCPA, which is structurally similar to UCP1, and is abundantly expressed in the thermogenic spadix. Here, we conducted a series of comparative analyses of UCPs with six transmembrane domains, SfUCPA and rat UCP1, and TM5-deficient SfUCPB, using a heterologous yeast expression system. All UCPs were successfully expressed and targeted to the mitochondria, although the expression level of SfUCPB protein was approximately 10% of rat UCP1. The growth rate, mitochondrial membrane potential, and ATP content were significantly lower in cells expressing SfUCPB than in those expressing rat UCP1 and SfUCPA. These results suggest that SfUCPB, a novel TM5-deficient UCP, acts as an uncoupling protein in yeast cells.

Nonlinear dynamics of homeothermic temperature control in skunk cabbage,Symplocarpus foetidus

Certain primitive plants undergo orchestrated temperature control during flowering. Skunk cabbage, Symplocarpus foetidus, has been demonstrated to maintain an internal temperature of around 20 degrees C even when the ambient temperature drops below freezing. However, it is not clear whether a unique algorithm controls the homeothermic behavior of S. foetidus, or whether such an algorithm might exhibit linear or nonlinear thermoregulatory dynamics. Here we report the underlying dynamics of temperature control in S. foetidus using nonlinear forecasting, attractor and correlation dimension analyses. It was shown that thermoregulation in S. foetidus was governed by low-dimensional chaotic dynamics, the geometry of which showed a strange attractor named the "Zazen attractor." Our data suggest that the chaotic thermoregulation in S. foetidus is inherent and that it is an adaptive response to the natural environment.

EFFECTS OF SPRING ACORN AVAILABILITY ON BLACK BEAR DIET, MILK COMPOSITION, AND CUB SURVIVAL

We investigated the role of changing abundance of spring foods on female American black bear (Ursus americanus) diet, milk composition, and cub survival in western Massachusetts. We hypothesized that diets would change, percentage milk fat would be higher, and cub survival would be higher in a year when overwintered hard mast was more abundant. We obtained paired samples of milk from 7 adult female bears across consecutive reproductive cycles during which spring diets differed; 1 year followed a bumper acorn (Quercus rubra) crop and estimated spring diets were >25% acorns; the other year followed an extremely poor acorn crop and spring diets were estimated to be 99% skunk cabbage (Symplocarpus foetidus). Postdenning milk was higher in fat (26.7% versus 18.2%; P = 0.0557) during the spring when acorns were abundant, but we did not identify any carryover affect to cub survival. We suggest that adult female black bears compensate for changes in food availability by eating greater volumes of alternative foods, and perhaps allocate resources primarily to milk production; the bears appear to be able to produce milk of adequate quality to sustain cubs, regardless of spring diet.