Taxonomic Significance of the Occurrence and Distribution of Secretory Canals and Tanned Cells in Tissues of some Members of the Nigerian Clusiaceae

Abstract

The occurrence and distribution of secretory cavities and tanniniferous cells in the tissues of four species of Nigerian Clusiaceae were investigated by light microscopy (LM), with respect to their taxonomic values. These species were Harungana madagascariensis (Lam.) ex Poir., Garcinia kola Heckel., Allanblackia floribunda Oliv. and Pentadesma butyracea Sabine. Results showed significant variations in the location, distribution and density of these micro-anatomical features in these species. Tanned cells and secretory cavities were observed in the epidermis, collenchyma, parenchyma, phloem and pith tissues of all the species except for H. madagascariensis. Correlation analysis between these variables were very highly significant at (P > 0.01) and correlated positively (r = 0.97), (r = 0.73) and (r = 0.75) for G. kola, A. floribunda and P. butyracea, respectively. Similarly, simple linear regression analysis were very highly significant at (p < 0.001) and positive with (r² = 0.96), (r² = 0.86) and (r² = 0.97) for G. kola, A. floribunda and P. butyracea, respectively, while these were neither significant non-positive for H. madagascariensis at (p < 0.447) and (r² = 0.17), respectively. High level of tanned cells in epidermal and phloem tissues suggested its protective functions, potential source of dye for tanning industry and the presence of bioactive component for ethno medicinal potency. The taxonomic values of these features are discussed.

Keyword: Taxonomic values, Secretory cavities, Tanned cells, Nigerian Clusiaceae