Abstract Detail

Anatomy and Morphology

Czander, Autumn [1], Foulkes, M. Raine [1], Ionta, Gretchen  [2].

Variation in pollen size in four species of meadow beauties (Rhexia; Melastomataceae) collected in North Florida and Georgia.

Rhexia comprises 13 species of facultative and obligate wetland plants inhabiting a variety of damp and wet habitats in Eastern North America, ranging from Nova Scotia to the West Indies, and west to eastern Texas. The evolutionary history of the meadow beauties is confounded by extensive hybridization and polyploidization, with several species putatively of hybrid origin and others appearing in polyploid series (e.g. in R. cubensis n=11, 22, or 33). We examined inter- and intraspecific variation in pollen size in four species of Rhexia collected from 13 locations within the Ordway-Swisher Biological Station (Hawthorne, Florida), and from 3 additional sites in North Florida and Georgia. Rhexia mariana, the widest-ranging, morphologically most variable species in the genus, was best represented, with 39 specimens; R. nashii, R. cubensis, and R. petiolata were also included in this study. Field-collected plants were cultivated and stamens were harvested on the morning of anthesis; for each sample, ten pollen grains from a single anther were measured. Mean diameters showed a significant difference between species (p<0.001), and R. nashii & R. cubensis (mean pollen dia. 28.4 & 28.9µm) were each statistically different from both R. mariana & R. petiolata (mean dia. 24.5 & 22.1µm); interestingly, the larger mean pollen size reported here in R. nashii & R. cubensis is mirrored in the much larger petals and longer hypanthia typical for these species, as compared to the smaller floral features commonly found in R. mariana & R. petiolata, which were found to have more diminutive pollen on average in this study. Rhexia mariana samples analyzed alone showed significant differences between certain populations, but we were unable to identify environmental or other factors that might account for this pattern.

1 - Georgia College & State University, Department Of Biological And Environmental Sciences, Campus box 081, Milledgeville, GA, 31061, USA
2 - Georgia College And State University, Department Of Biological And Environmental Sciences, Campus Box 81, Milledgeville, GA, 31061, United States

Keywords:
Rhexia
Melastomataceae
pollen grain size.

Presentation Type: Poster
Session: P, Anatomy and Morphology
Location: Grand Ballroom - Exhibit Hall/Mayo Civic Center
Date: Monday, July 23rd, 2018
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PAM017
Abstract ID:928
Candidate for Awards:Developmental and Structural Section best poster