MICROMORPHOLOGICAL ANALYSES OF STOMATA AND EPIDERMAL CELL AMONG DIFFERENT SPECIES IN THE GENUS Premna L. (LAMIACEAE)

Abstract

The genus Premna in Lamiaceae family was categorized into two groups namely P. serratifolia-group and P. trichostoma-group by de Kok in 2013. The division was based on three distinct morphological characters which are twigs, calyx and fruit. This group category lacks of anatomical and micromorphological evidence and solely based on those morphological characters. Therefore, in this study, anatomical and micromorphological characters were analysed on six Premna species (P. interrupta, P. serratifolia, P. trichostoma, P. tomentosa, P. parasitica and P. odorata) from few localities in Peninsular Malaysia. They were investigated to determine the size of stomata and some epidermal characters among the species members to provide some evidence towards the division. The methods involved in this research were epidermal peel preparation and field emission microscopy (FESEM) technique. The stomata were observed under the microscope and also photographed at different magnifications. Based on the observation, primary sculpturing pattern of leaf surface showed four types of patterns and labelled as type 1, 2, 3 and 4. All six species of Premna have the same undulating, four sides and number of anticlinal walls which showed shared characteristics of the genus. However, the stomatal size, sculpturing and distribution show some taxonomic significance in identification of the species. Stomatal size shows significant difference between species which ranged from 3 µm to 20 µm. Three types of stomata presented at the abaxial surface, anisocytic, paracytic and diacytic while four different types of stomatal sculpturing were observed which are type 1, 2, 3, 4 and stomatal distribution resulted in variances in stomatal density. Therefore, the division of Premna as suggested by de Kok was supported based on stomatal type and secondary stomata sculpturing evidences.