Evolution and Biological Activity of Cycadophyta

Authors

Gustavo M. De Angeli, FIUFollow

Document Type

Thesis

Degree

Master of Science (MS)

Major/Program

Biology

First Advisor's Name

Oscar Valverde Barrantes

First Advisor's Committee Title

Committee chair

Second Advisor's Name

DIego Salazar Amoretti

Second Advisor's Committee Title

Co-committee Chair

Third Advisor's Name

Javier Ortega

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Michael Calonje

Fourth Advisor's Committee Title

Committee member

Keywords

cycads, functional traits, biflavonoids, evolution

Date of Defense

3-31-2023

Abstract

Worldwide, environment gradients effects on leaf physical and chemical defenses traits, were studied in very phylogenetically heterogeneous plants; leading to results that may be confounding. To address this, in this study, we focused on a single Order, Cycadales. We collected data for 8 key leaf traits from 80 Cycads species around the world (~27% of all cycad species known). The leaf traits included, foliar area, leaf mass area, thickness, leaf density, toughness, water, hinokiflavone and amentoflavone content, all of which are closely related to trade ‘offs between plant defenses and leaf construction. We quantified the relative contributions of environment variables to leaf trait variation for all species comparing results to a recent phylogeny data base. Our results suggest that the climatic adaptation of leaves in this ancient group required a decoupling between traits associated with tissue investment and leaf thickness. Adaptation to more humid, warmer areas required an increase in chemical protection against herbivores, whereas drier environments with high temperature range, selected for thicker leaves better protected against excessive radiation. These findings contribute to the understanding of Cycads evolution characteristics across environmental gradients.

Identifier

FIDC010975

ORCID

https://orcid.org/0000-0001-6227-0362

Recommended Citation

De Angeli, Gustavo M., "Evolution and Biological Activity of Cycadophyta" (2023). FIU Electronic Theses and Dissertations. 5141.
https://digitalcommons.fiu.edu/etd/5141