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The ‘Male Flower’ of Ricinus communis (Euphorbiaceae) Interpreted as a Multi-Flowered Unit

One of the most exciting questions in botany refers to the nature of the angiosperm flower. While most flowering structures are easily identified as flowers, there are few examples lying in-between flowers and inflorescences. Such an example is the staminate unit (‘male flower’) in Ricinus communis...

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Autores principales: Claßen-Bockhoff, Regine, Frankenhäuser, Hebert
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204434/
https://www.ncbi.nlm.nih.gov/pubmed/32426355
http://dx.doi.org/10.3389/fcell.2020.00313
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author Claßen-Bockhoff, Regine
Frankenhäuser, Hebert
author_facet Claßen-Bockhoff, Regine
Frankenhäuser, Hebert
author_sort Claßen-Bockhoff, Regine
collection PubMed
description One of the most exciting questions in botany refers to the nature of the angiosperm flower. While most flowering structures are easily identified as flowers, there are few examples lying in-between flowers and inflorescences. Such an example is the staminate unit (‘male flower’) in Ricinus communis (Euphorbiaceae) famous for its branched ‘staminal trees.’ The units were controversially interpreted in the past. Today, they are seen as flowers with multiple branched stamen-fascicles. In the present paper, the recently described floral unit meristem is used to reinterpret the staminate units in Ricinus. This meristem shares almost all characteristics with a flower meristem, but differs from it in the number of fractionation steps resulting in multi-flowered units. Reinvestigation of the development confirms previous studies illustrating up to six fractionation steps before the meristem merges into anther-formation. Fractionation starts early at a naked meristem, covers simultaneously its whole surface, shows an all-side instead of unidirectional splitting pattern and continues repeatedly. Based on the present knowledge, it is plausible to interpret the ‘male flower’ as a floral unit with multiple staminate flowers each reduced to a single anther. This interpretation is in accordance with the many examples of reduced flowers in the Euphorbiaceae.
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spelling pubmed-72044342020-05-18 The ‘Male Flower’ of Ricinus communis (Euphorbiaceae) Interpreted as a Multi-Flowered Unit Claßen-Bockhoff, Regine Frankenhäuser, Hebert Front Cell Dev Biol Cell and Developmental Biology One of the most exciting questions in botany refers to the nature of the angiosperm flower. While most flowering structures are easily identified as flowers, there are few examples lying in-between flowers and inflorescences. Such an example is the staminate unit (‘male flower’) in Ricinus communis (Euphorbiaceae) famous for its branched ‘staminal trees.’ The units were controversially interpreted in the past. Today, they are seen as flowers with multiple branched stamen-fascicles. In the present paper, the recently described floral unit meristem is used to reinterpret the staminate units in Ricinus. This meristem shares almost all characteristics with a flower meristem, but differs from it in the number of fractionation steps resulting in multi-flowered units. Reinvestigation of the development confirms previous studies illustrating up to six fractionation steps before the meristem merges into anther-formation. Fractionation starts early at a naked meristem, covers simultaneously its whole surface, shows an all-side instead of unidirectional splitting pattern and continues repeatedly. Based on the present knowledge, it is plausible to interpret the ‘male flower’ as a floral unit with multiple staminate flowers each reduced to a single anther. This interpretation is in accordance with the many examples of reduced flowers in the Euphorbiaceae. Frontiers Media S.A. 2020-04-30 /pmc/articles/PMC7204434/ /pubmed/32426355 http://dx.doi.org/10.3389/fcell.2020.00313 Text en Copyright © 2020 Claßen-Bockhoff and Frankenhäuser. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Cell and Developmental Biology
Claßen-Bockhoff, Regine
Frankenhäuser, Hebert
The ‘Male Flower’ of Ricinus communis (Euphorbiaceae) Interpreted as a Multi-Flowered Unit
title The ‘Male Flower’ of Ricinus communis (Euphorbiaceae) Interpreted as a Multi-Flowered Unit
title_full The ‘Male Flower’ of Ricinus communis (Euphorbiaceae) Interpreted as a Multi-Flowered Unit
title_fullStr The ‘Male Flower’ of Ricinus communis (Euphorbiaceae) Interpreted as a Multi-Flowered Unit
title_full_unstemmed The ‘Male Flower’ of Ricinus communis (Euphorbiaceae) Interpreted as a Multi-Flowered Unit
title_short The ‘Male Flower’ of Ricinus communis (Euphorbiaceae) Interpreted as a Multi-Flowered Unit
title_sort ‘male flower’ of ricinus communis (euphorbiaceae) interpreted as a multi-flowered unit
topic Cell and Developmental Biology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7204434/
https://www.ncbi.nlm.nih.gov/pubmed/32426355
http://dx.doi.org/10.3389/fcell.2020.00313
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