The morphology and density of pasak bumi (Eurycoma longifolia, Jack) leaf trichomes in six natural populations in Indonesia

Abstract

Eurycoma longifolia Jack is one of the important medicinal plants in Indonesia and is used in many traditional and modern medicines. Information on trichome characteristics of E. longifolia and its relationship with environmental factors is limited. The purpose of this study was to investigate the morphology and density of the leaf trichomes of E. longifolia, to observe its correlation with geographic and climate factors of population, and to identify trichome characters that can discriminate among populations. The morphology and density of the leaf trichome of six populations of E. longifolia were investigated using a light microscope. Analysis of variance, correlation analysis, principal component analysis (PCA), and clustering of the population were performed. The results of this study detected two types of glandular trichome in the leaf of E. longifolia, namely peltate and capitate. Analysis of variance showed a significantly different density of trichome among populations. Variation of trichome density among populations may be caused by different micro-environmental of population and genetic factors of plant individuals. We confirmed that geographic and climate factors of the population have significant positive/negative correlations with types and density of trichomes. The PCA analysis exhibited trichome density could be used as a distinguishing characteristic among populations.