Chinelo A. Ezeabara

Transverse sections (T/S) of the roots of Citrus aurantifolia (Christm.) Swingle, C. grandis Osbeck, C. limon (L.) Burm.f., C. paradisii Macf., C. reticulata Blanco and C. sinensis (L.) Osbeck were investigated using standard plant anatomical procedures. The pores of roots of all the species were oval in shape. The sizes of the pores found in C. sinensis were the lowest range (117–27 µm in length; 108–27 µm in width). The distributions of axial parenchyma were confluent parenchyma in Citrus aurantifolia, C. grandis, C. paradisii, C. reticulata and C. sinensis, whereas it was vasicentric aliform parenchyma in C. limon. Citrus limon, therefore, possessed an advanced feature which indicated that it evolved at a different rate compared with others. The study revealed anatomical characters of these Citrus species and hence shed light on their affinity. The characters of secondary wood, therefore, could be applied as additional characters by plant taxonomists in resolving the ongoing controversy in the taxonomy of Citrus.