Phyllotactic patterning of gerbera flower heads

Teng Zhang1, Mikolaj Cieslak2, Andrew Owens2, Feng Wang1, Suvi K. Broholm1, Teemu H. Teeri1, Paula Elomaa1, and Przemyslaw Prusinkiewicz2
1 University of Helsinki
2 University of Calgary

Abstract

Phyllotaxis, the distribution of organs such as leaves and flowers on their support, is a key attribute of plant architecture. The geometric regularity of phyllotaxis has attracted multidisciplinary interest for centuries, resulting in an understanding of the patterns in the model plants Arabidopsis and tomato down to the molecular level. Nevertheless, the iconic example of phyllotaxis, the arrangement of individual florets into spirals in the heads of the daisy family of plants (Asteraceae), has not been fully explained. We integrate experimental data and computational models to explain phyllotaxis in Gerbera hybrida. We show that phyllotactic patterning in gerbera is governed by changes in the size of the morphogenetically active zone coordinated with the growth of the head. The dynamics of these changes divides the patterning process into three phases: the development of an approximately circular pattern with a Fibonacci number of primordia near the head rim, its gradual transition to a zigzag pattern, and the development of a spiral pattern that fills the head on the template of this zigzag pattern. Fibonacci spiral numbers arise due to the intercalary insertion and lateral displacement of incipient primordia in the first phase. Our results demonstrate the essential role of the growth and active zone dynamics in the patterning of flower heads.

Reference

Teng Zhang, Mikolaj Cieslak, Andrew Owens, Feng Wang, Suvi K. Broholm, Teemu H. Teeri, Paula Elomaa, and Przemyslaw Prusinkiewicz. Phyllotactic patterning of gerbera flower heads. Proceedings of the National Academy of Sciences USA 118(13), e2016304118, 2021.

View the teaser video here (13.2 MB) or at the Viikki Plant Science Centre
Download the paper from the publisher's site.

Download Model 1 here (TGZ archive, 8.2 MB)
Download Model 2 here (TGZ archive, 8.2 MB)
Download Model 3 here (TGZ archive, 16 MB)

You will need VLAB to run the models. They were tested using VLAB verison 4.5.1-3520 on macOS 10.13 (High Sierra).