WOOD ANATOMICAL STUDIES REVEAL TAXONOMIC RELATIONSHIPS, ENVIRONMENTAL INFLUENCE AND PULP POTENTIAL IN FOUR TAXA OF Mussaenda (RUBIACEAE) GROWN IN NIGERIA

Abstract

Current study was carried out to assess the taxonomic, ecological significance, and paper making potential of four taxa of Mussaenda L. (Rubiaceae) viz., M. elegans, M. erythrophylla, M. philippica var. aurorae, and M. ‘Dona Aurora’ through wood anatomical studies. Each of the taxa was collected from its natural region of provenance in two different ecological zones (Derived Savanna and Tropical Rainforest) of Nigeria. Observations from different planes of sections were made and wood maceration was carried out for fibre morphology. Absent to scanty paratracheal axial parenchyma, septate fibres, pitted vessels, storied heterocellular rays, and simple perforation plates were common features in all taxa. However, multiseriate and wider rays distinguished the exotic species from the indigenous species, and the semi-diffuse porous wood pattern was a unique feature in M. ‘Dona Aurora’. Quantitative data showed considerable variations in case of fibre lengths among the four taxa i.e. M. elegans, M. erythrophylla, M. philippica var. aurorae, and M. ‘Dona Aurora’ and was recorded 0.80 ± 0.02 µm, 0.70 ± 0.05 µm, 0.65 ± 0.03 µm and 0.64 ± 0.04 µm respectively. These observations showed that all species belong to Wood Type II of Rubiaceae and support their inclusion in the Tribe Mussaendeae and Order Ixoroideae. The influence of environmental factors was evident in the significant elongation of wood vessels of samples collected from more humid areas, but with no significant effect on their paper-making potential. More so, M. “Doña Aurora”, had general scores, would be most suitable for pulp and paper making.