Morphological and leaf anatomical characters in relation to C3 and C4 photosynthetic pathways in the genus cyperus L. in southwestern Nigeria.

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Date
2013
Journal Title
Journal ISSN
Volume Title
Publisher
Obafemi Awolowo University
Abstract
This study investigated leaf morphological and anatomical characters of twelve species from the genus Cyperus – a genus known to contain species with C3 and C4 photosynthetic pathways – in order to check the usefulness in delimiting the species along their photosynthetic pathways as well as enhancing the overall taxonomy of the genus and species. It was also employedin classifying species which have not been classified before into C3 or C4. Species investigated were; C. articulatus L., C. compressus L., C. difformis L., C.dilatatus Schum. & Thonn., C. distans L., C. esculentus L., C. haspan L., C. imbricatus Retz., C. iria L., C. rotundus L., C. sphacelatus Rottb. and C. tenuiculmis (Boeck.) Hooper, collected from different locations within Southwestern Nigeria. The habit and habitat of species were noted on the field and qualitative morphological characters such as inflorescence form and arrangement, spikelet color and arrangement, stem shape, edge and base, presence or absence of rhizome and tubers were recorded. Quantitative morphological characters such as plant height, stem length and width, rhizome thickness, leaf length and width, bract length and width, ray length, spikelet length and width as well as glume length were measured with a metric ruler to the nearest centimeter. Counts were also made for number of bracts, rays and glumes. For anatomical studies, standard anatomical procedures for epidermal peel clearing and cross sectioning of leaves were followed. Leaf anatomical characters that were investigated include:stomata density, interstomatal distance, vein-stomatal distance, Kranz tissue, maximum lateral cell count, one cell distant count, leaf thickness, mesophyll thickness and interveinal distance. The results revealed some morphological characters:the compound umbellate inflorescence, digitately arranged spikelets and short spikelets not over 1cm long are quite delimiting for C3species, andnone of C4 species shared combination of these characters. Anatomical characters such as stomatal density, interstomatal distance, vein-stomatal distance, leaf thickness and mesophyll thickness are found to be useful in enhancing overall taxonomy of these species but they do not serve as good diagnostic tools for photosynthetic pathway characterization within the genus. However, the presence or absence of Kranz tissue, interveinal distances, one cell distant count and maximum lateral cell count proved to be very useful in elucidating the infrageneric affiliations of these species along the different photosynthetic pathways. This study concluded that combinations of morphological and anatomical characters can be used in delimiting these species along different photosynthetic pathways as well as to enhancing their overall taxonomy. It confirmed that C. difformis andC. haspan are C3 species while the rest follow the C4 photosynthetic pathway. This study also established C. dilatatus – a species which has not been classified before – as one that belongs to the group of C4 species.
Description
xiii, 93p
Keywords
Morphological, Leaf anatomical, Photosynthetic, Genus cyperus, Taxonomy
Citation
Ayeni, O.B. (2013). Morphological and leaf anatomical characters in relation to C3 and C4 photosynthetic pathways in the genus cyperus L. in southwestern Nigeria. Obafemi Awolowo University
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