Publication Date

Summer 2012

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Biological Sciences

Advisor

Susan C. Lambrecht

Keywords

climate, floral, morphology, phenotype, plasticity, variation

Subject Areas

Biology; Plant biology

Abstract

Phenotypic plasticity in plants is a vital adaptive response to changing environmental conditions. Floral and vegetative morphology often varies as biotic and abiotic factors vary. Variation is the basis of evolution, and natural selection, acting on trait variation, can lead to speciation. For this study, floral and vegetative character traits of false babystars (Leptosiphon androsaceus, Polemoniaceae) were analyzed within four populations at Henry W. Coe State Park in 2011. Traits were measured to assess changes in size along a moisture availability gradient. Stable carbon isotope ratio samples were collected to measure integrated water-use efficiency (WUE) as it related to precipitation and floral size. Sizes of floral and vegetative characters varied significantly between the drier and wetter regions. Floral and vegetative character sizes for L. androsaceus decreased from the wetter to the drier region. The ratio of floral area/leaf area increased as precipitation decreased, suggesting that leaves may have incurred a physiological cost from floral growth within the drier region. A difference in WUE, as it related to trait size and precipitation, was not found for this study year. These results provide evidence that floral and vegetative characters of L. androsaceus vary in size in response to water-limiting conditions.

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