Stomata in Polygonaceae

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Polygonum plebeium (Small knotweed)

The family Polygonaceae in West Africa: Taxonomic significance of leaf epidermal characters.

by Ayodele A.E., Olowokudejo J. D. (2006)

abiodun_ayodele
Abiodun E. Ayodele, University of Ibadan, Nigeria
james_olowokudejo
James Dele Olowokudejo, Uni-versity of Lagos, Nigeria

in South African J. Bot., 72: 442–459 – DOI: 10.1016/j.sajb.2005.12.009 –

http://www.sciencedirect.com/science/article/pii/S0254629906000342

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Plate 1. Photomicrographs of leaf surfaces of Polygonaceae (Epidermal cells and stomata) A, B, C and D: Tribe Polygoneae. A. Polygonum plebeium. Adaxial surface showing anisocytic stomata with striae and polygonal cells. B. P. plebeium. Abaxial surface showing anisocytic stomata with striae and polygonal cells. C. Oxygonum sinuatum. Adaxial surface showing striated polygonal cells with straight to curved anticlinal walls and anomocytic/diacytic stomata. D. O. sinuatum. Abaxial surface showing striated polygonal cells with straight to curved anticlinal walls and anomocytic/diacytic stomata. E and F: Tribe Perscarieae. E. Persicaria nepalensis. Adaxial surface showing striated polygonal and irregular cells with cyclocytic stomata. F. P. nepalensis. Abaxial surface showing irregular cells with sinuate walls and anomocytic stomata. Scale bar = 60 μm. G – L: Tribe Persicarieae.
Abstract
Comparative studies have been carried out on the leaf epidermal features of the species in the family Polygonaceae in West Africa.
Epidermal cells are mainly isodiametric in Symmeria paniculata, irregular or more often polygonal with curved, straight and undulate to sinuate anticlinal walls.
A few species e.g. Polygonum plebeium, Oxygonum sinuatum, Persicaria nepalensis and Harpagocarpus snowdenii have striations on their epidermal walls.
All species except Afrobrunnichia erecta and H. snowdenii are amphistomatic and the family is characterized by a wide range of stomata types such as the anisocytic in P. plebeium, cyclocytic in S. paniculata and a few Persicaria, anomocytic, diacytic, parallelocytic and paracytic which is regarded as the basic type for the family based on its widest occurrence among the species.  However, different stomata types may occur on the same leaf surface.
The unicellular, or multicellular, uniseriate aggregated trichomes are significant in the recognition of taxa in the Persicaria except in P. senegalensis forma albotomentosa which has short uniseriate flagelliform trichomes.
The significance of these observations is discussed in relation to the taxonomy of the family.

Published by

Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

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