Botany & Plant Ecology.
Invasive species are a threat to ecological communities and ecosystem function. A number of shrubs have invaded plant communities in Michigan. Nonetheless, a deep understanding of mechanisms of invasion remains elusive. One promising hypothesis, the enemies release hypothesis, posits that invasive species enter their new homes with few enemies to regulate their growth. Invasive plant research has focused on herbivory; however, growth may be hindered significantly by pathogens as well. This research quantifies visible damage to leaf tissues and characterizes fungi from both leaf and root tissue. Two native (Rubus strigosus and Cornus foemina) and four invasive species (Elaeagnus umbellata, Lonicera maackii, Rhamnus cathartica, and Rosa multiflora) were studied. Samples were taken twice, with a 15 day separation between sampling dates. Following surface sterilization, small specimens of each species were plated onto potato dextrose agar. Following 4-5 days of growth, fungal growth was categorized based on morphological features into putative species. Interestingly, more morphospecies of fungi were found in invasive than native species (14 in invasive, 12 in native). The number of shared species was high. Pairwise Jaccard indices of similarity ranged from 0.57 to 0.91. These results are not consistent with a role for fungi in the enemies hypothesis of invasion.
Physiological Basis by Which Common and Glossy Buckthorn Compete with One Another, Hawthorn, and Gray Dogwood. Jake Kalkman and David Dornbos, Calvin College
Common (Rhamnus cathartica) and glossy buckthorn (Rhamnus frangula) are non-native, invasive plant species invading US Midwest natural areas. Both frequent the Calvin College campus. Like other invasive plants, buckthorn competes with native plants for light, water, and nutrients, displacing native species. The objective of this project was to compare light use efficiency (LUE), water use efficiency (WUE), and stomatal characteristics of the buckthorn species and two co-habiting native species, hawthorn (Crataegus) and gray dogwood (Cornus racemosa), in sun and understory environments on the Calvin campus in 2016 and 2017. Contrary to expectation, glossy outperformed common buckthorn in sun locations and particularly at higher light intensities. Glossy buckthorn produced higher water use efficiencies than common in both sun and shaded understory environments, potentially by virtue of a higher density of smaller stomates on lower leaf surfaces. Chlorophyll content did not vary in meaningful ways. Hawthorn grew faster than both buckthorn species in sun but was intermediate in growth rate between the buckthorn species in the understory locations. Gray dogwood grew the slowest of the four species in all environments. These results enable land stewards to target mitigation efforts of buckthorn where restoration activities have the greatest likelihood of success.
MASS: A Tool for Morphological Analysis of Size and Shape of Leaves. Tya Chuanromanee, James Cohen, and Gillian Ryan, Kettering University
Morphometries is the practice of identifying shape variation and shared features in and among groups. In botany, morphometries is used to quantify the effects of mutation, environment, climate, and other characteristics on plant morphology, such as in leaf shape. Various software programs have been developed to assist in morphometries, but these programs were single-purpose (e.g., only for image capture, measurements, or analyses), which means that a full morphometric analysis can require as many as five different tools. We propose and develop a comprehensive and flexible software program to streamline the morphometric analysis process without relying on multiple different programs. In addition to collecting basic morphological characteristics, such as length and width, the program supports common morphometric methods and statistical analyses, allowing the user to select desired features separately. In our talk, we will demonstrate the use of the software by analyzing apple leaves and sugar maple leaves. The modular design and robustness of the software gives the software sufficient flexibility to be potentially useful in analyzing other plant components, such as flower petals.
Bog Vegetation in the Grand Rapids Area: A Comparative Study across Sites and through Time (1901 to 2017). Devani Antuma, Jenna Van Donselaar, Garrett Crow, and David Warners, Calvin College
Michigan's natural landscape includes a variety of ecosystems, including highly specialized wetlands classified as bogs. Although bogs in Michigan have been well studied, most of these efforts have focused on bogs in the northern sections of the state. However, in the latter 1890s, Emma J. Cole, a renowned botanist, published the Grand Rapids Flora, which included an in-depth catalog of the bog species found in the greater Grand Rapids area. Cole's account is still the most comprehensive and current catalog of plants found in West Michigan. Our project is part of a larger multiple-year effort undertaken at Calvin College to revisit and inventory all of Emma Cole's collection locations. We compared inventories that have recently been done at three modern bogs, Dead-lake Bog, Saul Lake Bog, and Miller Lake. These bogs are found within the area from which Cole collected specimens when preparing her book. Comparing a comprehensive current day list from these sites with Emma Cole's historic catalog of bog plants provides a rare opportunity to compare bog vegetation from a limited geographic area before and after 11 5 years or urban and agriculture development.
Changes in Tundra Vegetation Due to Warming. Katlyn Betway and Robert Hollister, Grand Valley State University
A rise in the average global temperature is one of the most predominant effects of climate change, and the Arctic is experiencing significant warming. To understand the impacts of warming on tundra we present the results of over 20 years of experimental warming at four study sites in northern Alaska. Vegetative sampling, using the point frame method, showed significant changes in cover across sites. At the Atqasuk Dry site bryophytes and lichens decreased over time and with experimental warming. At the Atqasuk Wet site bryophytes decreased while deciduous shrubs and graminoids increased over time and with experimental warming. At the Barrow Dry site, deciduous shrub and graminoids increased over time and with experimental warming. At the Barrow Wet site bryophytes decreased while graminoids increased over time and with experimental warming. The consistency of the documented changes in cover over time and as a result of experimental warming suggest that they will continue in future decades and that each site has a unique trajectory; therefore, it is important to monitor these ecosystems as they respond to climate change.
Fraxinus americana Plant Soil Feedback Legacy Effects on Seedling Regeneration. Sarah McCarthy-Neumann and Hannah Rokosz, Alma College
With introduction of the emerald ash borer (EAB) extensive tree mortality of white ash, Fraxinus americana, has occurred. A less obvious impact on seedling recruitment may be due to changes in plant-soil feedback dynamics as adults die. Persistence of PSFs as legacy effects (e.g., the ability to impact subsequent vegetation over a period of time) in forest ecosystems has yet to be examined. The overarching goal of this study is to provide insights into the longer-term consequences for ash, whose seedlings are unaffected by EAB, and effect of adult mortality on recruitment for other native tree species.
Testing for PSF legacy effects, we assessed seedling survival and growth over 10 weeks in high light (greenhouse) and low light (growth chamber) with three tree species (Acer saccharum, Fraxinus americana and Primus serotina) to four soil treatments--soil that had been cultured in situ by healthy, EAB infected, newly dead (died within 1-2 years), or old dead (died 5-10 years ago)--or with sterilized soil taken from healthy adults, allowed us to test whether soil microbes were the mechanism creating these PSFs.
Trends showed strong PSF legacy effects, lessening that ash regeneration will thrive after the adults in a stand attacked by EAB.
Percent Lignin and Cellulose across Light Levels and Age of Quercus alba and Q. rubra. Erica Krol and Sarah McCarthy-Neumann, Alma College
During tree seedling establishment, lignin increases allowing the herbaceous seedlings to become woody. Slower lignification rates can be a mechanism for higher seedling mortality during this critical phase as they result in a longer time period when seedlings are susceptible to damping-oft diseases. We hypothesize that lignification rates will be slower in low light environments. In summer 2017, in experimental plots at Alma's Ecological Field Station, we planted seedlings of two species (Quercus alba and Q. rubra) into three light levels. Six seedlings per species and light level were harvested starting in week 3 through week 6. Percent lignin and cellulose (%ADF) for seedling stems were measured using an ANKOM 200. Using ANOVA, we found that %ADF increased over time for both species ([F.sub.(3,42)] = 6.48, p = 0.001). In addition, light availability influenced lignin and cellulose levels for Q. rubra with significantly greater %ADF in high vs. medium light and Q. rubra has greater %ADF in both low and high light than Q. alba seedlings ([F.sub.(2,42)] = 3.78, P = 0.031).
Observed Vegetation Change in Northern Alaska across the Landscape. Jacob Harris, Timothy Botting, and Robert Hollister, Grand Valley State University
This study documents changes across tundra plant communities near Utqiagvik, and Atqasuk, Alaska. In each location, 30 1[m.sup.2] plots distributed equally across the landscape were sampled annually, via a point-frame method, from 2010 to 2017. Plant specimens were identified to species and distributed into 6 functional groups based on their taxonomy (bryophytes, deciduous shrubs, evergreen shrubs, forbs, graminoids, and lichens). There were significant changes in cover between years. The largest directional changes were increased cover of graminoids and deciduous shrubs in Atqasuk and to a lesser degree in Utqiagvik. Correlations between abiotic factors and changes in graminoid and deciduous shrub cover suggest that changes are being driven by temperature in Utqiagvik but not in Atqasuk. Further monitoring is necessary to understand observed changes and to better predict future changes due to climate change.
An Update on the Middle Miocene Ponderosa Floral Assemblage From Payette Lake, McCall, Valley County, Idaho. Patrick F. Fields, College of Idaho and Olivet College
The Ponderosa fossil leaf assemblage was first reported in 2016 and at that time consisted of about 25 different recognizable forms, of which 12 were taxonomically identified. The present status elevates the number of identified megafossils to about 50 taxa. In addition to the more common species in the genera Ginkgo, Sequoia, Alnus, Carya, Cercidiphyllum, Fagus, Platanus, Quercus, Salix, Ulmus, and Zizyphoides, several new occurrences have been noted, including Acer, Ceanothus, Cornus, Hiraea, Liquidambar, Magnolia, Mahonia, Nymphaea, Pterocarya, Smilax, and the first North American fossil occurrence of Cotinus. Preliminary identifications based on fossil pollen consist of about 18 recognized forms, and confirm the presence of several of the more common megafloral genera, and add Abies, Castanea/Lithocarpus, Choenopodiaceae, Ostrya, and assorted fungal and monolete spores. These findings continue to support the suggestion that the flora represents a lacustrine/riparian assemblage with a significant overbank/floodplain floral component, to which we can now add a forest slope component. Acknowledgement is due to Drs. Barbara Ertter, Christopher Davidson, and William C. Rember.
Effect of a Living Mulch of White Clover (Trifolium repens) on Soil Properties and Yield of the Medicinal Herb, Purple Coneflower (Echinacea purpurea). Carrie D. Herp and Sheila A. Blackman, Grand Valley State University
Agricultural practices must adapt to future increased crop demand coupled with an unpredictable climate and natural resource scarcity. Living mulches have been shown to improve agroecosystem function and crop productivity and thus may offer one option to address some of the resultant challenges. The aim of our work was to test whether a white clover (Trifolium repens) living mulch would increase the productivity of the medicinal plant, Echinacea purpurea, while simultaneously improving soil ecosystem function. E. purpurea is growing in economic importance hut plant establishment in the first year after transplant is unusually sensitive to weed competition. This is problematic in organic production systems which prohibit herbicide use. We found that white clover positively affected soil moisture, temperature, and respiration, and neutralized pH but had no effect on nutrient or organic matter content. Furthermore, despite having a positive effect on the early growth of E. purpurea transplants, final harvested biomass was significantly reduced when plants were grown with clover. Although several studies show that a white clover living mulch improves soil fertility and productivity in many crops, our results demonstrating that it may decrease Echinacea productivity suggest that particular crop-mulch species pairs must be chosen judiciously after empirical testing.
Investigating Intraindividual Variation and Mutation in an Apple Tree (Malus domestica). Jim Cohen, Gillian L. Ryan, and Solomon Turgman-Cohen, Kettering University; Christina Wheeler, Grand Valley State University
In plants, somatic and germline cells are not distinct from one another, meaning any somatic mutations could potentially be carried through to new segments of the plant and to gametes. Specifically, within trees, modular growth patterns allow these somatic mutations to be passed to unique segments within a single tree. This can lead to genetic variation within a single individual, and subsequent variation in fruits and seeds (apart from variation based on meiosis). In apples, genetic variation within a single individual can result in diversity in apple size, shape, taste, and seed viability, all of which are important factors in the uniformity of the products of apple farming. To better understand the potential for genetic variation within one apple tree, variation among eight samples from across one individual apple tree were examined using genome resequencing and single nucleotide polymorphism (SNP) identification with FreeBayes, which was implemented on the web-based platform Galaxy. Results suggest the strictness of SNP calling criteria greatly affect the number of SNPs identified. In FreeBayes, the number of SNPs ranges from 2,286,568, with lenient criteria, to 127,401, with strict criteria, which accounts for 0.3% to 0.01% of the genome varying across one apple tree.
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|Title Annotation:||fungal infections in shrubs, plant competition. morphometrics technology|
|Date:||Sep 22, 2018|
|Previous Article:||Biochemistry & Molecular Biology.|