Ruffatto, Danielle M. , Molano-Flores, Brenda .
Variation in gender ratios of the gynodioecious prairie species Lobelia spicata L. across a latitudinal gradient.
The high variability in gender ratio observed for gynodioecious species has been linked to genetic, biotic and abiotic factors among populations and across a latitudinal gradient. This study focuses on assessing whether two abiotic factors, temperature and precipitation, are driving the relationship between gender ratio/reproductive output measurements across a latitudinal gradient for the gynodioecious prairie species Lobelia spicata L. Data on latitude, gender ratio, reproductive output [i.e. fruit set, seed number per fruit, seed biomass, percent seed germination] and mean temperature and precipitation from May to July [growing season] were collected for 11 populations across Illinois during the summer of 2008 and 2009. As with studies conducted on other gynodioecious species, the percent of females within L. spicata populations showed a strong negative relationship with latitude, such that there were higher percentages of females in southern than in northern populations. Temperature is likely the driving force behind the latitude/gender ratio relationship because it showed a strong negative relationship with latitude and a significant positive relationship with gender ratio in both 2008 and 2009. However, less precipitation in southern populations during intermittent years may also account for some of the latitudinal variation in gender ratio. The reproductive output measurements did not show any trends with the exception of female and hermaphrodite seed biomass, which showed a consistent negative relationship with latitude and strong positive relationship with temperature. Thus, it appears that stressful conditions, such as high temperatures and low precipitation, may favor the success of female plants within populations of L. spicata while high temperatures result in the production of larger seeds by both female and hermaphrodite plants.
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1 - University of Illinois, Department of Plant Biology, 1816 S. Oak St. , Champaign, IL, 61820, USA
2 - University of Illinois, Illinois Natural History Survey, 1816 S. Oak St., Champaign, IL, 61820, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Forsyth Room/Chase Park Plaza
Date: Tuesday, July 12th, 2011
Time: 10:30 AM