Abstract Detail

Systematics Section

Penagos Zuluaga, Juan Carlos [1], van der Werff, Henk [2].

Evaluation of the relationship of Aiouea with Cinnamomum, Ocotea and Mocinnodaphne (Lauraceae) using stomatal and cuticular leaf characters.

In a previous molecular study, Aiouea was found in two quite separate clades. The first clade relates species of Aiouea with the species of the Ocotea insularis group. The second clade relates species of Aiouea with neotropical species of Cinnamomum and Mocinnodaphne. This grouping is also supported by floral characters.
Methods: Cuticle and stomatal characters of forty species were examined under light microscopy and scanning electron microscopy, and characters were measured from digital images. Samples were taken from herbarium collection of the Missouri Botanical Garden. Variables with high loadings from a principal component analysis were considered as the most important and evaluated separately to determine their utility from a taxonomic perspective. Multilevel analysis was then used to determine the relationship between environmental variables and these characters, taking into account species-level characteristics.
Results: Three groups were recognized in the PCA. The three most important characters were stomatal rim width, stomata and aperture length.
The first group has a wide stomatal rim and includes all the species of Aiouea from South America, neotropical species of Cinnamomum, and Mocinnodaphne. The second group has a narrow stomatal rim and includes all the species of Aiouea from Central America and northwest South America and the species of O.insularis group from Central America. A third group includes two species (A.guatemalensis and A. inconspicua) without a stomatal rim. These two species are the northern distribution range of Aiouea and the lack of molecular information does not allow further inference about relationship with other groups in the family.
Preliminary results from multilevel analyses show a correlation between environmental variables and stomata length vary at species-level, and are do not suggest that they are conservative characters within the different clades.
Conclusion: Results show that some cuticular characters are still useful in taxonomy being conservative characters in clades. Conversely, stomatal length can vary as a specific response to environmental variation and should be treated more carefully in taxonomy.

Broader Impacts:

1 - University of Missouri - Saint Louis, Department of Biology, One University Boulevard, R223 Research Building, St. Louis, MO, 63121-4400, USA
2 - Missouri Botanical Garden, P.O. Box 299, St. Louis, MO, 63166-0299, USA

Keywords:
leaf anatomy
epidermal characters.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM
Number: PSY008
Abstract ID:649