The meristematic activity of the endodermis and the pericycle and its role in the primary thickening of stems in monocotyledonous plants

The meristematic activity of the endodermis and the pericycle and its role in the primary thickening of stems in monocotyledonous plants

Author Menezes, Nanuza L. de Google Scholar
Elbl, Paula M. Google Scholar
Cury, Graziela Google Scholar
Appezzato-da-Gloria, Beatriz Google Scholar
Sasaki, Karen L. M. Google Scholar
Silva, Cristiane G. da Autor UNIFESP Google Scholar
Costa, Gisele R. Google Scholar
Lima, Vera G. A. Google Scholar
Institution Inst Biociencias
Universidade de São Paulo (USP)
Universidade Federal de São Paulo (UNIFESP)
Univ Guarulhos
Abstract Background: It had long been thought that a lateral meristem, the so-called primary thickening meristem (PTM) was responsible for stem thickening in monocotyledons. Recent work has shown that primary thickening in the stems of monocotyledons is due to the meristematic activity of both the endodermis and the pericycle.Aims: the aim of this work is to answer a set of questions about the developmental anatomy of monocotyledonous plants: (1) Do the stem apices of monocots have a special meristematic tissue, the PTM? (2) Are the primary tissues of the stem the same as those of the root? (3) Is there good evidence for the formation of both the cortex and the vascular tissue from a single meristem, the PTM, in the shoot and from two distinguishable meristems in the root? (4) If the PTM forms only the cortex, what kind of meristem forms the vascular tissue?Methods: Light microscopy was used to examine stem and root anatomy in 16 species from 10 monocotyledonous families.Results: It was observed that radially aligned cortical cells extend outwards from endodermal initial cells in the cortex of the roots and the stems in all the species. the radial gradation in size observed indicates that the cortical cells are derivatives of a meristematic endodermis. in addition, perfect continuity was observed between the endodermis of the root and that of the stem. Meristematic activity in the pericycle gives rise to cauline vascular bundles composed of metaxylem and metaphloem.Conclusion: No evidence was obtained for the existence in monocotyledons of a PTM. Monocotyledons appear to resemble other vascular plants in this respect.
Keywords endodermal initial
endodermis
monocotyledons
pericycle
primary thickening meristem
stem thickening
Language English
Sponsor Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Date 2012-01-01
Published in Plant Ecology & Diversity. Abingdon: Taylor & Francis Ltd, v. 5, n. 2, p. 153-165, 2012.
ISSN 1755-0874 (Sherpa/Romeo, impact factor)
Publisher Taylor & Francis Ltd
Extent 153-165
Origin http://dx.doi.org/10.1080/17550874.2011.604925
Access rights Closed access
Type Article
Web of Science ID WOS:000311559700003
URI http://repositorio.unifesp.br/handle/11600/34479

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