Abstract Detail

Development and Structure

Holliday, Aaliyah [1], Martinez-Gomez, Jesus [2], Rose, Irving Jason [3], Specht, Chelsea [4].

The Evolution of the Monocot Inflorescence using a Phylogenetic Framework.

In angiosperms, the inflorescence consists of a main axis and a series of lateral branches with flowers that can be arranged in diverse architectures. These specialized regions can be distinctively altered from the rest of the plant’s vegetative system and play an important role in optimizing a plant’s reproductive success by facilitating the transfer of pollen, the development of fruit, and plant-pollinator interactions. Stebbins was the first to examine inflorescences in a macroevolutionary framework and also noted that the complex development of inflorescences demonstrates the evolutionary trends of maintenance of organization and adaptive modification along the lines of least resistance. Despite their importance, the terminology used to describe complex inflorescence architecture is not uniform among authors and the evolutionary transitions among inflorescence types are not well understood. In order to gain a deeper understanding of evolutionary processes that dictate the diversification of these structures, this study aims to consolidate and analyze pre-existing data on inflorescence morphology across monocots using a phylogenetic framework. We systematically searched through the literature to identify and collect morphological data for all major monocot families. We coded inflorescences for approximately 2300 species from approximately 500 citations. Inflorescence morphologies were scored using a code of classifications sensu Endress 2010 that provides a simplified method to classify inflorescences into racemes, cymes, panicles, spikes, umbels, and solitary inflorescences using branching orders and patterns. Some categories were very common. For example, racemes were found in every order. We inferred ancestral states using continuous time markov models (aka ancestral state reconstruction). We used the all rates different model, the equal rates model, and the symmetrical rates model. Ancestral nodes for many orders were inferred to be racemes, this is consistent with prior developmental morphological studies To assess if our models are adequate for these data, we simulate 1000 datasets using parameters estimated from the best fit model then compare our simulations to our observed data. In conclusion, we use our comparative phylogenetic framework to infer the patterns of morphological evolution of inflorescence organization for each major family of monocots.

1 - 130 University Avenue, Ithaca, NY, 14850, United States
2 - Cornell University, Plant Science, Mann Library 237 Mann Drive Cornell University, Ithaca, NY, 14850, United States
3 - Cornell University, Plant Science, Mann Library 237 Mann Drive Cornell University, Ithaca, NEW YORK, 14853, United States
4 - Cornell University, Section of Plant Biology & the L.H. Bailey Hortorium, 502 Mann Library, Ithaca, NY, 14853, United States

Keywords:
Ancestral State reconstruction
phylogenetics
Liliales
Arecales
Commelinales
inflorescence
phylogenetic framework
monocots.

Presentation Type: Oral Paper
Session: DS1, Development and Structure I
Location: /
Date: Tuesday, July 20th, 2021
Time: 11:15 AM(EDT)
Number: DS1006
Abstract ID:740
Candidate for Awards:Developmental and Structural Section Undergraduate Student Registration Award