CAPITULUM: The International Compositae Alliance Newsletter

Understanding capitulum development: Gerbera hybrida inflorescence meristem as an experimental system

Teng Zhang

https://orcid.org/0000-0002-5189-3289

Paula` Elomaa

https://orcid.org/0000-0001-6512-0810

DOI: https://doi.org/10.53875/capitulum.01.2.04

Keywords: laser ablation, live-imaging, meristem, micro-CT

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Abstract

Inflorescences, the flower-bearing structures in plants, show enormous diversity in nature. Their architecture,
in terms of number and arrangement (phyllotaxis) of flowers, play a central role in reproductive success and
adaptation of plants, as well as yield in crops. We apply Compositae capitula, or flower heads, as our model system
to study inflorescence development. The unique architecture of capitula, often composed of morphologically and
functionally distinct types of flowers, is considered the key innovation for the evolutionary success of this largest
family of flowering plants. Moreover, the arrangement of individual flowers in intersecting spirals in capitula represent
an iconic example of the geometric regularity found in nature. Our aim is to explore the gene regulatory networks
that control patterning of the Compositae inflorescence meristems and their subsequent development. In this
brief review, we summarize the recent technological developments and tools that allow us to explore and follow
meristem patterning early on – already before we can see any visual changes in them. These include visualization
of capitulum development by X-ray micro-computed tomography (micro-CT), live-imaging of dissected meristems
on tissue culture media, and application of laser ablation to disrupt meristem organization and to follow its repatterning.
We anticipate that these methods are applicable to distinct species to promote comparative studies and
understanding of developmental diversity of capitula within Compositae.