Comparative Leaf Anatomy and Micromorphology of Thunbergia erecta (Benth.) T. Anderson and Thunbergia laurifolia Lindl. in Peninsular Malaysia

Abstract

Comparative leaf anatomy and micromorphology study was carried out on two selected species from the genus Thunbergia Retz. of Acanthaceae subfamily Thunbergioideae. These two investigated species were T. erecta and T. laurifolia from Peninsular Malaysia. The leaf anatomical study involve several methods such as crosssection using sliding microtome on the petioles, midribs, lamina and marginal, leaf epidermal peeling, leaf clearing and observation under a light microscope. The leaf micromorphology method involve the observation under a scanning electron microscope (SEM). This study aimed to investigate the taxonomic value of leaf anatomy and micromorphology characteristics of genus Thunbergia. The results have shown that there were five common characteristics present in both species studied and several variable characters that might be useful for species differentiation of T. erecta and T. laurifolia. The five common characteristics recorded were the presence of raphide, sinuous anticlinal walls, diacytic stomata, majority opened and minority closed venation in lamina and the presence of peltate glandular (unicellular terminal) trichome. The variable characteristics included were petiole, and marginal outlines, types of vascular bundles, the presence of druse, marginal venation, stomata occurrence, types of wax, cuticular sculpturing and types of trichomes. In conclusion, findings in this study showed that leaf anatomical and micromorphological characteristics possessed taxonomic value that can be used in the species identification for the genus Thunbergia specifically for T. erecta and T. laurifolia.