Abstract Detail

Systematics

Rivera, Patricia [1], Terrazas, Teresa [2], Villaseñor, Jose Luis [2].

Comparative leaf anatomy of Asteraceae in a xerophytic scrub and its relation to cytogenetic characters.

In angiosperms ploidy level and chromosome numbers are found related to some plants attributes as growth form and leaf characters. Particularly they have been related to guard cells length, stomatal frequency, specific leaf area (SLA) and mesophyll cell size.
Asteraceae is the most diverse and abundant angiosperm family in the world. Mexico is considered as one of the main centers of diversification of the family. This diversity can be observed in morphology, growth forms and cytogenetic characters. Probably this diversity is related to the ability of the family to live in different ecosystems around the world. Understanding the patterns of relationship between cytogenetic and morpho-structural characters and growth forms in Asteraceae, can help us understand why it has been so successful in such diverse environments. The study of Mexican genera may be used to better understand how the diversification of the family occurred and the role played by the phylogeny and the environment to model the leaf morphology.
A study was conducted to evaluate the relationship between cytogenetic and leaf characters, as well as the relationship between growth form and the aforementioned characters as well as the effect of phylogeny on these relationships. Fifty-two species representing 12 tribes of Asteraceae present in a xerophytic scrub in the Mexico City basin were studied. The relationship between chromosome number and ploidy level with foliar anatomical features and growth forms were evaluated using independent contrasts phylogeny and phylogenetic signal tests.
Our results indicate that triploid, tetraploid and hexaploid species tend to have higher SLA and stomatal length than the diploid species. We found a correlation between chromosome number and leaf area and leaf dry mass. These results indicate that species with high chromosome numbers tend to have bigger and heavier leaves than those with low chromosome numbers. It appears to be a relation between chromosome number and ploidy level with growth form but the statistical significance is low.
Moreover, the correlation between cytogenetic and foliar anatomical characteristics is low in most cases. Chromosome number (x), leaf thickness, leaf area and leaf dry mass presented phylogenetic signal. The relationships between chromosome number with growth form, guard cell length with stomatal density and leaf thickness, and leaf area with dry mass are dependent on the relations between Asteraceae clades. More information is needed about the phylogenetic position of the genera and species of Asteraceae of Mexico to achieve more conclusive results.

1 - Instituto de Biologí­a, Universidad Nacional Autónoma de, Botánica, Tercer Circuito Exterior, S/n, Coyoacan, Cd. Universitaria, 04510
2 - Instituto de Biologí­a, Universidad Nacional Autónoma de, BotÁnica, Tercer Circuito Exterior, S/n, Coyoacan, Cd. Universitaria, 04510, Mexico City

Keywords:
Asteraceae
leaf anatomy
comparative method.

Presentation Type: Poster
Session: P, Systematics Section/ASPT Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
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: PSY049
Abstract ID:250
Candidate for Awards:None