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Forced Flowering in Mandarin Trees under Phytotron Conditions
Published on: March 6, 2019
Open and closed inflorescences: more than simple opposites.
Kester Bull-Hereñu1, Regine Classen-Bockhoff
1Institut für Spezielle Botanik, Johannes Gutenberg Universität, D-55099 Mainz, Germany. bull@uni-mainz.de
Journal of Experimental Botany
|August 28, 2010
Summary
Open inflorescences, lacking a terminal flower, are not solely explained by the CLAVATA-WUSCHEL loop. Novel mechanisms involving genes like GERBERA REGULATOR OF CAPITULUM DEVELOPMENT 2 and spatial constraints suggest multiple developmental pathways for inflorescence termination.
Area of Science:
- Plant developmental biology
- Evolutionary developmental biology
- Molecular genetics
Background:
- The open inflorescence, characterized by the absence of a terminal flower, is traditionally explained by the maintenance of stem cells in the inflorescence meristem's central zone (CZ), regulated by the CLAVATA-WUSCHEL pathway.
- Mutations in Arabidopsis TERMINAL FLOWER LOCUS 1 disrupt this pathway, leading to terminal flower development.
Purpose of the Study:
- To investigate alternative ontogenetic pathways contributing to the evolution of open inflorescences across different angiosperm taxa.
- To challenge the universal applicability of the CLAVATA-WUSCHEL regulatory loop in explaining inflorescence termination.
Main Methods:
- Comparative analysis of inflorescence development across diverse plant families.
- Histological studies of inflorescence meristems.
- Investigating the role of MADS-box genes, such as GERBERA REGULATOR OF CAPITULUM DEVELOPMENT 2, in inflorescence development.
Main Results:
- In Gerbera, the SEPALLATA-like gene GERBERA REGULATOR OF CAPITULUM DEVELOPMENT 2 actively prevents terminal flower formation, independent of a persistent CZ.
- Comparative histology reveals the absence of a retained CZ in the inflorescence meristems of many 'open' inflorescence families.
- Evidence suggests that spatial constraints within the inflorescence meristem may influence terminal flower determination in some taxa.
Conclusions:
- The evolution of open inflorescences in angiosperms is not governed by a single ontogenetic pathway.
- Multiple mechanisms, including genetic regulation beyond the CLAVATA-WUSCHEL loop and physical constraints, contribute to the diverse strategies of inflorescence termination.
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