Comparative leaf and stem anatomy of ten Piper species from Indonesia

The genus Piper with over 700 species distributed in tropical and subtropical areas of the world has a considerable number of species with economic importance as spices and herbal medicine. In this study the anatomical characters of leaf and stem on 10 species of Piper from Bogor Botanical Garden, Indonesia were observed in relation with their function as oil-accumulating organs. The objective of this study was to explore the anatomical variability among species. Observations on anatomical characters were done on leaf epidermal and cross section as well as stem cross section prepared using paraffin embedding method. Results indicated that there were structural variations on the epidermal features, mesophyll, secretory cells and secretory cannals of leaves, as well as variation on the ratio of medullary and peripheral vascular bundles on stem. Results of this study provide additional taxonomic evidence to confirm differences between Piper species, and serve as supporting data for identification based on internal structures. Data on the comparative anatomy of leaf and stem also contributes to the selection of the right materials for the extraction of essential oils from various Piper species based on the presence of secretory cells.