Foliar micro-morphology of Gasteria bicolor haw. (Asphodelaceae) from South Africa.
BACKGROUND
The succulent genus, Gasteria, which comprises 16 species, is endemic to South Africa and has its main centre of distribution in the Savanna Region of the Eastern Cape. Whereas G. bicolor has been investigated phyto-chemically and pharmacologically, not much data concerning the anatomical and micro-morphological features can be found in literature.


METHODS
This study was undertaken, using light and scanning electron microscopy to obtain information on the micro-morphological features of this important medicinal plant to facilitate its identification and authentication. The elemental composition of the leaf was determined by energy dispersive X-ray spectroscopy (EDXS).


RESULTS
The epidermal cells are either hexagonal or pentagonal in form, and are compactly arranged with undulate anti-clinal cell walls. The epidermal cell width was approximately 50 µm. Stomata apertures are elliptical and the upper epidermis of the leaf has paracytic stomata which are slightly raised above the epidermal surface with 4 to 5 subsidiary cells surrounding each stoma. Based on the EDXS microanalysis, the mineral crystals present at the level of the mesophyll of G. bicolor were probably mixtures of calcium oxalate, calcium sulphate and silica.


CONCLUSIONS
The co-occurrence of aluminum suggests the potential role of the crystals in detoxification of aluminum and heavy metals, as reported previously.
Department of Botany, Faculty of Science and Agriculture, University of Fort Hare, P/Bag X1314, Alice, 5700, South Africa.
Wilfred Mbeng
WM
Otang
Department of Botany, Faculty of Science and Agriculture, University of Fort Hare, P/Bag X1314, Alice, 5700, South Africa.
Donald Scott
DS
Grierson
Department of Biochemistry and Microbiology, Faculty of Science and Agriculture, University of Fort Hare, P/Bag X1314, Alice 5700, South Africa ; Department of Biochemistry and Microbiology, Faculty of Science, PO Box 63, University of Buea, Cameroon.
Roland
R
Ndip
D002129:Calcium Oxalate / Q000378:metabolism; D002133:Calcium Sulfate / Q000378:metabolism; D003460:Crystallization; D019668:Liliaceae / Q000378:metabolism / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D059828:Plant Cells / Q000648:ultrastructure*; D019441:Plant Epidermis / Q000648:ultrastructure*; D010936:Plant Extracts / Q000592:standards; D018515:Plant Leaves / Q000378:metabolism / Q000648:ultrastructure*; D054046:Plant Stomata / Q000648:ultrastructure; D010946:Plants, Medicinal / Q000378:metabolism / Q000648:ultrastructure; D012822:Silicon Dioxide / Q000378:metabolism; D013019:South Africa
D010936:Plant Extracts; D002129:Calcium Oxalate; D012822:Silicon Dioxide; D002133:Calcium Sulfate
Foliar micro-morphology; Gasteria bicolor; light microscopy; scanning electron microscopy