Amborella – Bearing witness to the past ?
Résumé
Amborella trichopoda (Amborellaceae) is a shrub endemic to New Caledonia in the Southwest Pacific region. This plant suddenly became famous when molecular phylogenetic studies revealed that this sole species is likely the sister taxon to all other angiosperms. It has thus been a prime research model for reconstructing plant evolution and gaining insight into what the earliest angiosperms looked like. A wealth of studies on Amborella have now shed considerable light on its genome, morphology, anatomy, physiology, development, and architecture – this research is reviewed in this article. While Amborella likely retained some ancestral traits, critical character reconstructions have also highlighted some derived and sometimes unique characters in this species. The history of Amborella is also tied to the South Pacific archipelago of New Caledonia, its homeland. It was part of the New Caledonian biogeography puzzle and its genetic history shed light on the dynamics of its ecosystem, the rainforest understorey. Amborella is now cultivated in botanical gardens and has been the focus of some conservation measures that will also benefit other species in this biodiversity hotspot.