Comparative foliar anatomy of three Khaya species(Meliaceae)used in Nigeria as antisickling agent

摘要

Khaya belongs to the family Meliaceae.In Nigeria the genus is represented by three species viz;K.senegalensis A.Juss.,K.grandifoliola C.DC.and K.ivorensis A.Chev.Comparative foliar anatomy of the three Khaya species was carried out to identify and describe distinctive anatomical characters that could possibly be used to delimit the three taxa.Transverse section,epidermal peels and cleared leaves of these three species were made.Characteristic similarity and disparity in the tissues arrangement as well as cell inclusions were noted for description and delimitation.The three Khaya species studied had essentially the same anatomical features,e.g.,venation pattern having open polygonal areoles and the veins terminals biforkated.However,there were characters that seem to be species specific,e.g.,vien termination number and areole width.The leaf epidermal studies of the three species revealed similarities in stomatal type which are generally staurocytic,epidermal cells and undulating anticlinal cell walls but stomata density varied.Hexacytic stomata is only observed in the abaxial surface of K.grandifoliola which distinguished this species from the others.The leaf petiole shape of the three species are round and difficult to distinguish into adaxial and abaxial surfaces.The cuticle is striated,vascular bundles are heart shape,conjoint,concentric and amphivasal,but are different in epidermal and collenchyma cell layer numbers.The leaf transverse sections of the three Khaya species studied have conjoint,concentric and amphicribral bundles while the leaf cuticle of K.senegalensis and K.grandifoliola are striated but that of Khaya ivorensis is non-striated.