Abstract Detail



Ecology

Laport, Robert [1], Aronson, Ellinor [2].

Stomatal Size and Density Variations in the Polyploids of Larrea tridentata: Landscape Level and Areas of Co-Occurrences.

Polyploidy, the duplication of all chromosomes in an organism’s genome, is an exceedingly common genomic mutation that shapes flowering plant biodiversity. A single plant species can exist as multiple ploidal races, but plants with doubled chromosome complements often differ in phenotypic traits typically associated with environmental adaptations. While prior research suggests that stomatal sizes may be larger at higher ploidies, the relationship between stomatal size and density, whole plant water use, drought tolerance, and ultimately survival in polyploid species remains unclear. The southwestern desert creosote bush, Larrea tridentata (Zygophyllaceae), is an ecologically dominant shrub comprising diploids, tetraploids, and hexaploids that inhabit some of the most arid environments of the Chihuahuan, Sonoran, and Mojave Deserts. To test whether stomatal size differences are associated with ploidal differences or whether such differences arise from the environmental pressures of an arid environment, we measured the stomatal size and density from images of epidermal leaf peels. Peels were made for L. tridentata plants originating in areas of natural ploidy co-occurrence and nearby parapatric areas At the landscape level, we found that stomatal sizes increase with ploidy, but that stomatal densities tend to decrease with ploidy, resulting in similar predicted water use for co-occurring diploids, tetraploids, and hexaploids. However, where the ploidies co-occur, we found more complex patterns. Ploidal differences in stomatal size and density, exhibited patterns consistent with an influence of ploidy as well as environmental gradients.


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http://www.robertlaport.com/


1 - 1880 Vollintine Ave, Memphis, TN, 38107, United States
2 - 1207c Lakewood Dr, Greensboro, NC, 27410, United States

Keywords:
polyploidy
morphology
Larrea tridentata
water use
desert plants
co-ocurance.

Presentation Type: Oral Paper
Number: ECO2003
Abstract ID:131
Candidate for Awards:Ecological Section Best Graduate Student Paper


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