Systematic Significance of Leaf Anatomical Characteristics in Some Species of Mangifera L. (Anacardiaceae) in Thailand

Abstract

The leaf anatomical comparison of some species in genus Mangifera L. from Thailand, such as M. caloneura Kurz, M. camptosperma Pierre, M. duperreana Pierre, M. foetida Lour., M. indica L., M. odorata Griff., M. pentandra Hook.f. and M. qaudrifida Jack in Roxb. was provided. The specimens were investigated by peeling method, clearing method and transverse sections of lamina and petiole from each species of plant, and conducted an examination under light microscope to determine their systematic significance in species delimitation and identification. The consistent anatomical characteristics in all species are i) the typical cyclocytic and staurocytic stomata in adaxial and abaxial surfaces respectively; ii) the amphistomatic leaves; iii) the jigsaw shape with deeply undulate cell wall in adaxial epidermal cell; iv) the presence of sunken peltate trichomes on lamina and midrib; v) the presence of extension in bundle sheath to both surfaces; vi) the presence of fiber at the apex of leaf margin, midrib and petiole; vii) the presence of resin ducts; vii) the presence of mucilaginous cells in epidermis and midrib; and viii) the presence of prismatic crystals in mesophyll, midrib and petiole. In addition, the significantly anatomical features were useful for species delimitation which are as follows; i) the shape of epidermal cell; ii) the outline of leaf margin, midrib and petiole; iii) the shape of epidermal cell at the apex of leaf margin; iv) the layer of hypodermis; v) the number of palisade cell layers in lamina; vi) the presence of grouped fiber below sunken trichome; vii) the distribution of peltate trichome; viii) the presence of sclereid with ramiform-pitted in petiole; ix) the inclusion in each organ e.g. mucilaginous cell, crystal and starch grain; and x) the number of resin ducts in midrib and petiole.