Anatomical and topochemical features of the genera Acacia, Acaciella, Senegalia and Vachellia

Abstract

Molecular research has shown that the genus Acacia is in fact polyphyletic. The discussion about grouping the species of Acacia s.l. into monophyletic genera kept two International Botanical Congresses (Congresses 17 and 18) occupied and resulted in the general acceptance of the genera Acacia, Acaciella, Mariosousa, Senegalia and Vachellia. This raises questions about whether the wood of these new genera can be distinguished using established wood identification methods. Anatomical features of members from Acacia, Acaciella, Senegalia and Vachellia were examined and compared using transmission light microscopy. Topochemical characteristics were investigated using UV microspectrophotometry (UMSP) to identify differences in the distribution of phenolic compounds and cell wall lignification. The current study shows that the presence as well as the arrangement and dimensions of the axial parenchyma, as well as the height and width of the wood rays and fibre dimensions allow anatomical differentiation of the species studied. UMSP revealed the presence and distribution of phenolic compounds and differences in the degree of lignification between the genera. The aim of this paper is to highlight the potential of the applied methods to differentiate between the genera.