Abstract Detail

Ecology

Fernando, Thilina [1], Herlihy, Chris [2], Walck, Jeffrey [3].

Role of local adaptation to abiotic factors during seed germination stage in the maintenance of flower color polymorphism in Leavenworthia stylosa.

Understanding the mechanisms that maintain variation among populations is a main focus of evolutionary biology. Flower color which varies across the geographic range is a striking feature in many plant species. In addition to pollinator mediated selection, a growing body of knowledge suggests that this type of geographic variation can be maintained by local adaptation to abiotic conditions. Early life history stages of a plant such as seed germination may be especially sensitive to abiotic conditions such as soil type or water availability. Our study species Leavenworthia stylosa is a cedar glade endemic winter annual herbaceous species which is restricted to the inner central basin of Tennessee. It has two main flower color morphs: yellow and white, with most populations containing only one flower color morph. The goal of this study was to determine if local adaptation to abiotic factors and differential responses to abiotic stresses during the seed germination stage can play a role in maintenance of this geographic pattern of flower color distribution. We conducted two reciprocal transplant experiments, one with dormant seeds and one with non-dormant seeds. Seeds were collected from two yellow-flowered and two white-flowered source populations. Seeds from all source populations were transplanted into each of these four populations. To assess the effect of edaphic factors on seed germination in these L. stylosa sites, seed germination success of yellow and white morphs was determined in soil from each of the four transplant sites in the laboratory. In addition, seed dormancy break of the two color morphs was studied under a relative humidity gradient. Seed dormancy loss and seed germination of both color morphs was highest in white transplant sites. However, in the laboratory, there was no significant difference between white and yellow seed germination in each other’s soils. Under low relative humidity conditions white morphs showed a higher dormancy break compared to yellow morphs. Overall, our results suggest that the geographic pattern of the flower color variation cannot be explained by local adaptation to edaphic conditions at the seed germination stage.

1 - Middle Tennessee State University, Biology, P.O. Box 60, Murfreesboro, TN, 37132, United States
2 - Middle Tennessee State University, P.O. Box 60, Murfreesboro, TN, 37132, United States
3 - Middle Tennessee State University, 1301 East Main St, PO Box 60, Murfreesboro, TN, 37132, USA

Keywords:
local adaptation
seed germination
stress tolerance
Flower color polymorphism
Seed dormancy loss.

Presentation Type: Oral Paper
Session: 25, Ecology Section: Seed Ecophysiology
Location: 104/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 10:45 AM
Number: 25003
Abstract ID:168
Candidate for Awards:Ecological Section Best Graduate Student Paper