Abstract Detail

100 years of Baileyan Trends – Wood Evolution, Function and Future

Pace , Marcelo Rodrigo [1], Angyalossy, Veronica [2].

Using phylogenies to re-evaluate xylem and phloem evolution .

Theories on xylem and phloem evolution were advanced by Bailey and subsequent researchers based on parallels between tracheary cell attributes and the ideas of plant relationships of their times. At present, numerous phylogenies have been published and we have new paradigms of biological evolution, making it timely to reassess xylem and phloem diversification and test the proposals advanced in the past. Here we use the pantropical families Bignoniaceae from the Lamiids and Malpighiaceae from the Rosids to investigate xylem and phloem diversification and their possible correlations with habit and habitat transitions, using well-supported phylogenies and a broad sampling. Our results show that different lineages evolve in seemingly opposite directions in both xylem and phloem. In Bignoniaceae, the rays evolved in the Neotropical trees from heterocellular to homocellular, while in Neotropical lianas the opposite occurred. Ray height and width also seemed to be influenced by habit transitions, with lianas evolving higher and wider rays, and perforated ray cells. Axial parenchyma decrease in the transition from trees to lianas in both Bignoniaceae and Malpighiaceae, while vascular cambial variants appeared multiple times. Apotracheal parenchyma evolved from ancestral with only paratracheal parenchyma in both families. In the phloem of Bignoniaceae, some lineages evolved toward an increase in the number of sieve areas per sieve plate and others toward a decrease. This variation seems to be involved with the evolution of fiber abundance. Using phylogenies to reconstruct ancestral character states for more groups will likely help us shed light on the patterns of evolution and increase our understanding on the processes of diversification of the plant vascular system as a whole.

1 - Smithsonian Institution, Botany Department, Constitution Avenue & 10th Street NW, Washington, DC, 20560, USA
2 - Universidade De São Paulo, Botany, Rua Do Matao 277, Sao Paulo, SP, 05508-090, Brazil

Keywords:
Morphology and Anatomy
Wood anatomy
character evolution.

Presentation Type: Colloquium Presentations
Session: C06, 100 years of Baileyan Trends - Wood Evolution, Function and Future
Location: 106/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 9:15 AM
Number: C06005
Abstract ID:374
Candidate for Awards:None