Floristics and Plant Biology 2:00pm Saturday, April 6, 2002 Battelle Hall 115 Brian C. McCarthy-Presiding.
Savannas cover extensive areas of the Neotropics. There is a suite of factors that influence the vegetation of savannas, including climate, soil chemistry, soil drainage, and human activity. Our objective is to characterize the flora and vegetation of a Belizean savanna. The study site encompasses approximately 1 [km.sup.2] of the savanna community at Monkey Bay Preserve, a private preserve located in Northern Belize. Four 1 x 2 m plots were centered within each of 21 10 x 50 plots to obtain data on vegetation cover and environmental factors. Detrended Correspondence Analysis (DCA) and regression analyses were utilized to examine the relationship between vegetation and environment. Two communities, northern and southern sites, were different along the first axis of DCA. Two sample t-tests of environmental variables indicated elevation, percent slope, organic matter, P, Mg, Ca, CEC, Mn, and Fe were significantly different between communities (p<.05). 109 species in 50 families have been collected and identified.
2:15 A GIS MAP OF LICKING COUNTY, OHIO: VEGETATION AT THE TIME OF THE FIRST GOVERNMENT LAND SURVEYS. J. Michael Becher, email@example.com Amanda B. Fuller, firstname.lastname@example.org Institute for Environmental Studies, University of Wisconsin, Juliana C. Mulroy, email@example.com Dept of Biology, Denison University, Granville OH 43023. Since Paul Sears (1921) published a method for compiling early surveyors' witness tree data into a vegetation map, Ohio botanists have been at the forefront of pre-European settlement vegetation mapping. Ohio State botanist Transeau and his students mapped the majority of the state's counties in a series of ongoing projects culminating in the publication of Gordon's 1966 map, "Natural Vegetation of Ohio at the Time of the Earliest Land Surveys." Licking County, however, was omitted from the Ohio State projects. We created a digitized map of Licking County to characterize the county's pre-settlement vegetation and to allow comparisons between presettlement vegetation and other spatial data using Geographical Information Systems. To create the digital map, General Land Office records of witness trees were digitally transcribed onto a point theme using a Digital Raster Graph compilation of topographic maps for Licking County as a backdrop. Additional data such as surveyor's field notes were used to provide qualitative information for areas where witness tree data were not available. Five distinct vegetation types (beech-maple, oak-hickory, oak-hickory-chestnut, mixed mesophytic, and ell-ash-maple swamp forest) were identified within the county. Beech-maple dominated the Wisconsain-glaciated western portion and oak-hickory and oak-hickory-chestnut dominated the unglaciated eastern portion of the county.
2:30 EFFECTIVE POPULATION SIZE IN THE CLONAL, SELF-INCOMPATIBLE PLANT, HYMENOXYS HERBACEA. Lesley G. Campbell (1), firstname.lastname@example.org Brian C. Husband (2), email@example.com (1) 1735 Neil Ave., Dept of Evolution, Ecology and Organismal Biology, Ohio State University, Columbus OH 43210 and (2) Dept of Botany, University of Guelph, Guelph ON. Mating type diversity in populations of self-incompatible plants will decrease when effective size ([N.sub.e]) is less than 50, due to the impact of genetic drift on SI allele frequencies. To evaluate the impact of genetic drift on the clonal, self-incompatible plant Hymenoxys herbacea we 1) estimated effective size ([N.sub.e]) in two populations, under field conditions, using a demographic model for clonal plants, and 2) compared allozyme diversity to population size in 13 populations. Effective size was 2831 and 5856 in the two populations respectively and averaged 43% of the census population size. Elasticity analysis revealed that [N.sub.e] was most sensitive to changes in the survival and frequency of non-reproductive adults, and variation in asexual recruitment had a much larger impact than sexual reproduction. The percentage of the nine loci that were polymorphic ranged from 11 to 44% (mean=31); Nei's gene diversity averaged 0.2035 (SE=0.08). There was a significant relationship between allozyme diversity and population size (N or [N.sub.e]). These results suggest that genetic drift is detectable in H. herbacea populations but most populations are sufficiently large that its effect on SI allele diversity is negligible.
2:45 A PHYLOGENETIC ANALYSIS OF CRYPTIC MOONWORT SPECIES (BOTRYCHIUMs.s.:OPHIOGLOSSACEAE) USING rbcL AND trnL-F DNA SEQUENCES. Heather M. Hawke, firstname.lastname@example.org (Warren D. Hauk, email@example.com) SlayterBox 1223, Denison University, Granville OH 43023. Botrychium sensu stricto (s.s.), a group of ferns commonly called the moonworts, have a worldwide distribution, although the center of species diversity is in the mountains of western North America. Due to their relatively small size and simple morphology, species of Botrychium s.s. have been designated as "cryptic species". Thus, recognition and classification of moonwort species is challenging. The main goal of this research is to establish the evolutionary relationships among individual species using a molecular phylogeny. A phylogeny of moonworts constructed from DNA sequences of the plastid rbcL gene has already been established. However, this phylogeny contained 21 of the 24 currently recognized species in Botrychium s.s.. Thus, three species were not included. Using the rbcL gene, as well as the plastid trnL-F spacer region, the three remaining species (Botrychium pallidum, Botrychium boreale, and Botrychium gallicomontanum) will be sequenced and added to the molecular phylogeny. Botrychium pallidum is a key diploid, and is currently thought to be one progenitor of Botrychium minganense based on morphological similarities. Botrychium boreale and Botrychium gallicomontanum are putative tetraploids, and the identity of the chloroplast parents of these two species is unknown. The DNA sequences generated by this study should reveal the chloroplast parent of each of these species, and establish a more complete phylogeny of Botrychium s.s. species.
3:00 MICROBIOTIC CRUST COMMUNITIES FIX NITROGEN IN A TEMPERATE OAK SAVANNA. Roberta M. Veluci (1), firstname.lastname@example.org Kelly Ketcham (2), email@example.com Deborah A. Neher (1), firstname.lastname@example.org (1) Dept of Earth, Ecological and Environmental Sciences, Mailstop 604, University of Toledo, Toledo OH 43606, (2) Bowling Green State University.
Microbiotic crust is a biological soil crust composed of lichens, cyanobacteria, green algae, mosses, and fungi. Although crusts are known to be a dominant source of nitrogen input and stabilize soil surfaces to resist erosion in arid ecosystems, this study is the first one to examine ecological function of crust communities in xeric patches of temperate habitats. The study site is located within the Oak Openings Metropark of Northwest Ohio (41 [degrees] 42' 38" N, 83 [degrees] 41' 8" W). Using an acetylene reduction technique, we demonstrated that nitrogen fixation occurs in these crusts. Based on video imaging analysis of crust surface cover, proportion of moss cover explained more nitrogen fixation (p=0.0212) than did lichen, cyanobacteria or no cover (p [greater than or equal to] 0.15). Fluorescent microscopy (n=72) revealed that moss surfaces are covered with cyanobacteria responsible for fixing nitrogen. Looking at the effect of depth, populations of cyanobacteria were greater on moss surface (0-30 mm) than subsurface (31-60 or 61-90 mm) strata of these crusts (p < 0.0001). Based on the assumption that moss tends to occur only in late successional and well-established crusts, these data support our hypothesis that more nitrogen fixation occurs in well-established crust than intermediate or non-established crust. This study identified an important ecological function of microbiotic crust communities to promote conservation of lands with this habitat.
3:15 ATRIPLEX PROSTRATA (CHENOPODIACEAE) SEED DORMANCY AS INFLUENCED BY LONG-TERM COLD STORAGE. Christy T. Carter, email@example.com Lorena S. Brown and Irwin A. Ungar, Dept of Environmental and Plant Biology, Porter Hall, Ohio University, Athens OH 45701.
Atriplex prostrata produces two seed morphs. The larger brown seeds germinate readily when produced and the smaller black seeds require a cold stratification treatment to promote germination. While the seed morphs exhibit two different dormancy types, physiological changes in dormancy cycles may be slowed or altered during cold storage. We investigated the effects of long-term cold storage on the dormancy of dimorphic seeds of A. prostrata to determine whether these stored seed morphs exhibited annual changes in their dormancy cycles. Atriplex prostrata fruits collected in 1998 from an inland salt marsh in Rittman, Wayne Co., Ohio, were stored dry at 5 [degrees] C. Beginning in April 2000, 25 large and small fruits each were placed in 50 mm petri dishes with filter paper and 2 ml distilled water. Four replicates of each seed type were exposed to four temperature regimes (5/15 [degrees] C, 5/25 [degrees] C, 15/25 [degrees] C and 20/35 [degrees] C; 12h-night/12h-day) at monthly intervals over a one-year period. We found a significant interaction of seed size, temperature and month (p<0.05) on the germination of A. prostrata seeds. The capacity of seeds to germinate at different temperature regimes during storage at 5 [degrees] C varied with the month that seeds were removed from the cold treatment. Large seeds had their highest rate of germination in 20/35 [degrees] C temperatures whereas small seeds showed the highest rates of germination in 5/25 [degrees] C temperatures. Our data indicate that both seed types maintain endogenous rhythms of dormancy as indicated by their germination patterns.
3:30 EFFECTS OF ORGANIC MULCHING AND FERTILIZING TREATMENTS ON POPULATIONS OF RIVER BIRCHECTOMY CORRHIZAS Jennifer H. Wagner, firstname.lastname@example.org (Dr. Pierluigi Bonello email@example.com) The Ohio State University, Dept of Plant Pathology, 2021 Coffey Road Room 201 Kottman Hall, Columbus OH 43210.
A relative lack of research on the effects of compost in plant production and establishment is an obstacle to the rational use of this environmentally friendly resource. Mycorrhizas are symbiotic associations between some soil-borne fungi and the root systems of the majority of plants that have been demonstrated to be beneficial to the fitness of the plant hosts. In general, mycorrhizal colonization has been shown to improve the health status of trees. This study quantified and partially characterized populations of ectomycorrhizal fungi colonizing the roots of River birch (Betula nigra) trees grown in experimental plots under different treatments that included mulching with composted yard waste and shredded wood pallets, and N-P-K fertilization. The various mulching and fertilization treatments, alone and in combination, were expected to elicit changes in ectomycorrhizal populations. The procedure consisted of isolation, quantification, and morphological typing (i.e. morphotyping) of the ectomycorrhizae. Treatment appeared to affect the occurrence of morphotypes with a slightly higher diversity being found in the yard waste plots. Fertilization appeared to affect total root mass/length, while mulching significantly increased colonization percentage. Results of this study suggest that use of compost in tree establishment and maintenance may indirectly contribute to overall tree health by increasing natural mycorrhizal infection. Thus, this study indicates that composted soil amendments may be a viable and superior alternative to mineral fertilization.
3:45 APOSEMATIC (WARNING) COLORATION IN VASCULAR PLANTS OF SOUTHEASTERN OHIO. Brian C. McCarthy, firstname.lastname@example.org and Darrin L. Rubino, Dept of Environmental and Plant Biology, Ohio University, Athens OH 45701.
Aposematic coloration, the use of conspicuous colors to advertise unpleasant qualities to potential predators, is well documented in the animal kingdom. However, similar use of warning coloration in plants to advertise physical armaments (spines, thorns, or prickles) has been, until recently, unreported. The hypothesis was that plants using aposematic coloration to advertise physical armaments might be protected from future bouts of herbivory if herbivores associate color or a color pattern with unpleasantness. The goals of this investigation were to document the presence of aposematic coloration in the native and naturalized flora of southeastern Ohio (USA). Additionally, we wanted to gain a rudimentary idea regarding the commonality of this phenomenon among various taxonomic groups in the region. We defined aposematic plants as those with thorns, spines, or prickles that are colored so that they contrast with the vegetative structure(s) (leaf, stem, twig, rachis, petiole) on which they are borne. A high incidence of aposematism was observed in the plants of the region. Physical armaments of a wide range of color (white, yellow, yellow-green, red, maroon, tan, brown, and black) and color patterns were observed. Furthermore, aposematic coloration was found in a wide variety of genetically diverse taxa. We noted aposematic coloration in 44 species distributed among 23 genera in 17 families. Not all plants with physical armaments exhibited aposematic coloration. Future research into the possible role of aposematism in vascular plants could greatly expand our knowledge of plant-herbivore interactions.
4:00 DOES INDUCIBLE ANTIBIOTIC RESISTANCE IN ESCHERICHIA COLI K12 INVOLVE THE ACETYL PHOSPHATE PATHWAY? Abhishek Saharia, email@example.com (Dr. Dean Fraga), Dept of Biology, College of Wooster, WoosterOH44691
The use of antibiotics in the treatment and prevention of bacterial diseases in both humans and animals in the last 75 years has lead to the increase in the number of bacterial strains that are resistant to antibiotics. It has recently been observed that the resistance to antibiotics in E. coli K12 can be induced using chemorepellents such as sodium acetate. Chemoattractants, such as (L)-Aspartic acid, on the other hand, have been shown to increase susceptibility to antibiotics. This has been shown to occur in the absence of the mar operon, an operon initially thought to be the cause of inducible antibiotic resistance in E. coli. An alternative regulatory mechanism via acetyl phosphate regulatory pathways is proposed, since it has been shown to regulate the expression of outer membrane proteins (OmpF and OmpC). These proteins are thought to play a role in inducing antibiotic resistance. Thus, we have hypothesized that chemoattractants and chemorepellents may play a role in the level of antibiotic resistance in E. coli by affecting the levels of acetyl phosphate and indirectly affecting the levels the Omp proteins in the cell. This model shall be tested using acetyl phosphate regulatory mutants (which are unable to produce acetyl phosphate) to test whether antibiotic resistance may be induced in these backgrounds. If the acetyl phosphate regulatory mutants do not induce antibiotic resistance, the hypothesis that acetyl phosphate is important for this pathway can be demonstrated.
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|Publication:||The Ohio Journal of Science|
|Date:||Mar 1, 2002|
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