Linking indigenous knowledge, plant morphology, and molecular differentiation: the case of ironwood (Eusideroxylon zwageri Teijsm. et Binn.)

Abstract

The analysis of indigenous knowledge, morphological observations, and molecular variation are valid approaches to study plant biodiversity. A combination of these complementary methods allows a better understanding of the diversity within ironwood (Eusideroxylon zwageri Teijsm. et Binn.), an endangered ‘wild’ tropical tree species, at molecular and important functional traits. Ironwood belongs to the Lauraceae family. It is one of the most important species for construction wood in Indonesia because it is not vulnerable to termites and other ubiquitous tropical wood-destroying insects and fungi. Due to over-exploitation, populations of ironwood are decreasing and the species is included in the list of threatened tree species. Morphological variability of ironwood has been discussed and studied since the middle of the 19th century. However there is no comprehensive taxonomic assessment to the present time. The variability is mostly recognized by local people based on bark, wood and fruit characteristics. The present study has been conducted to answer whether the variation that is recognized by local people has a genetic basis. AFLPs were chosen as molecular markers best suited for this study due their capacity to estimate genome-wide genetic diversity. Morphological structure assessment was conducted to confirm specific characteristics of each variety. The percentage of polymorphic fragments was 52 %. UPGMA cluster analysis showed that 98 % of individual ironwood samples formed clusters according to their variety as recognized by local people. There was strong correspondence between clusters identified by AFLP analysis and morphological analyses.