Ecological Section use land-cover, and the number of growing degree days to identify habitat suitability using field-collected occurrences in MaxEnt. Predictors found to be uncorrelated and useful in minimizing variance inflation were used to develop species-specific habitat suitability maps, narrowing the list to 13 abiotic variables. Ensembles of small models (ESM) were used to account for the limited number of verified presence records for each taxon. These ESMs were built using all bivariate combinations of the 13 abiotic variables. A weighted average of the ESMs was used to develop the final species distribution map for each taxon. Here we present preliminary findings of model comparisons that were used to differentiate species based on an ecological niche modeling approach. Our next steps include identifying additional variables that may increase model performance and subsequently validate the developed models. Ultimately, our goal is to determine whether ecological niche models are consistent with the current taxonomic classification of these taxa as based on morphological and genetic analyses. 1
University Of Cincinnati, Department Of Biological Sciences, 614 Rieveschl Hall, Cincinnati, OH, 45221-0006, USA2Arkansas National Heritage Commission, 323 Center St., Suite 1500, Little Rock, AK, 72201, USA3WILLAMETTE UNIVERSITY, Department Of Biology, SALEM, OR, 97301, USA
252 TIM*
2
YAN, XUE QI 1 and DICKINSON,
Geographic parthenogenesis: what do allopolyploids get from their parents?
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n geographic parthenogenesis (GP) in plants, apomictic allopolyploids may occupy larger ranges and possibly more varied environments than do outcrossing diploid sister taxa. We have examined leaf architecture in relation to range and environmental amplitude in black-fruited Crataegus series Cerrones (section Douglasia) of the central Rocky Mountains and the adjacent Great Basin. This small agamic complex comprises diploid C. saligna Greene and tetraploids C. rivularis Nutt. and C. erythropoda Ashe. Examination of plastid DNA sequence variation and ITS haplotype diversity in these and other hawthorns has shown that this agamic complex also includes the continentally distributed red-fruited tetraploids C. chrysocarpa Ashe (section Coccineae) and C. macracantha Lodd. ex. Loud. (section Macracanthae) as pollen parents of the Cerrones tetraploids. Leaf architecture has been characterized in terms of leaf area, major vein density, minor vein density, serration density, and the inverse of the dissection index. For each of these five species we sampled leaves from three to five specimens collected from across the range of each species. Leaves were cleared and stained, and measured using ImageJ and FIJI. Values of the Bioclim environmental variables were obtained for all of the specimen collection localities. Sexually reproducing C. saligna has small fruits, small leaves with densely arranged major and minor veins, and a range more limited than those of all the other species except C. erythropoda. The apomictic red-fruited tetraploids have large fruits, leaves with less densely arranged veins, and the
largest ranges of any North American hawthorn species. The apomictic Cerrones allotetraploids are intermediate in fruit morphology and leaf traits. The range of C. rivularis is more extensive than that of C. saligna and of C. erythropoda, and smaller than the ranges of C. chrysocarpa and C. macracantha. All three Cerrones species share approximately the same subsets of the climatic niches of the two red-fruited species. Hybridization between C. saligna and one or both of the red-fruited species conferred on the hybrids (1) apomixis and the breakdown of gametophytic self-incompatibility; (2) intermediate leaf venation characteristics; and (3) fruits that are intermediate in size. In C. series Cerrones it appears that GP is due to (1) and (3) rather than adaptive features of leaf architecture. 1
University of Toronto, Ecology & Evolutionary Biology, 25 Willcocks St., Toronto, ON, M5S 3B2, Canada2Royal Ontario Museum, Natural History, 100 Queen's Park, Toronto, ON, M5S 2C6, Canada
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BUIDE, M. LUISA 2 and WHITTALL, JUSTEN BRYANT 3
Effects of UV radiation and shading on anthocyanin accumulation and flower production in the shore campion
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ne way to plants can adapt or acclimate to new environmental conditions is with the production of secondary metabolites. Anthocyanins, a group of flavonoids, may help plants to cope with the effects of a variety of biotic and abiotic stressors such as herbivory, pathogens, excess sun light radiation, cold, heat, drought or salinity. Anthocyanin pigments can be accumulated in every part of reproductive and vegetative plant organs, including petals, sepals, fruits, leaves or stems. Silene littorea is an annual plant with pink petals that grows in coastal populations from the Iberian Peninsula. In a previous study, we found a pattern of increasing accumulation of anthocyanins in petals, calyxes and leaves toward southern latitudes, which matches to a gradual increase of solar radiation and temperature, and a decrease of rainfall. Here, our aims are to investigate the role of solar radiation, including UV spectrum, in anthocyanin accumulation in reproductive and vegetative plant organs, and their relationship with flower and fruit production. We grow plants from four populations in a common garden experiment, located in a place with a solar irradiance similar to the maximum value found in natural populations. In a first experiment, plants were shaded to reduce 95% UV-PAR light. Open, fullsun plants showed at least two fold higher anthocyanin amount in calyxes and stems than shaded plants. In petals, anthocyanin production showed the same pattern, but differences were not significant. The total number of flowers of open plants was more than three times higher than those of shaded plants. In a second experiment, we carried out a UV filtration experiment using UVA+UVB transparent (methacrylate, transmittance > 280 nm) and UVA+UVB opaque (polycarbonate, transmittance > 380 nm) frames. In calyxes and stems, UV-present plants produced much higher amounts of anthocyanins than UV-absent plants. However, UVplants showed more than double flower production that UV-present plants. In conclusion, our findings suggest
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