Abstract Detail



Pteridology

Vasco, Alejandra [1], Ambrose, Barbara [2], Moran, Robbin C. [3].

The fern genus Elaphoglossum: systematics and molecular genetics of leaf development.

Elaphoglossum belongs to the leptosporangiate ferns, a group that accounts for more than 95% of the diversity of extant ferns. It has a pantropical distribution and is one of the most diverse genera of ferns with around 600 species. The genus belongs to the subfamily Elaphoglossoideae of the family Dryopteridaceae. Most members of the subfamily are characterized by divided leaves, however Elaphoglossum is distinguished by simple and entire leaves. Intriguingly, there are six species of Elaphoglossum that have divided leaves. Four of these belong to a monophyletic group of 20 species named Elaphoglossum section Squamipedia. Because of their divided leaves, these four species have sometimes been classified as part of segregate genera. The natural variation of simple and divided leaves in the genus provides a fascinating system to study the evolution and development of leaf dissection in ferns within a phylogenetic framework. To understand the relationships among species with simple and divided leaves of Elaphoglossum, we performed phylogenetic analyses with plastid data. These studies suggest that species with divided leaves are nested in Elaphoglossum but not monophyletic, having had independent evolutionary origins from ancestors with simple, entire leaves. To better understand the developmental basis for the generation of different leaf forms in ferns, we performed gene expression analyses of Histone H4 and Class I KNOX in simple and divided leaves of Elaphoglossum. Our results suggest that differences in patterns of cell division and in Class I KNOX expression mainly within the marginal meristem may underlie the distinct mature morphologies of simple and divided leaves in the fern genus Elaphoglossum. Our results also suggest that there is a conserved leaf developmental mechanism for leaf dissection between ferns and seed plants.


1 - Botanical Research Institute of Texas, 1700 University Drive, Fort Worth, Texas, 76107, USA
2 - The New York Botanical Garden, 2900 Southern Blvd, Bronx, NY, 10458, United States
3 - The New York Botanical Garden, 2900 Southern Boulevard, Bronx, New York, 10458, USA

Keywords:
evo-devo
ferns
Leaf Development
Taxonomy
Tropics.

Presentation Type: Oral Paper
Number: 0012
Abstract ID:358
Candidate for Awards:None


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