Format: ORAL

Anupama Sekhar1*, Ratchuporn Suksathan2, Piyakaset Suksathan2, Vinita Gowda1

1 Tropical Ecology and Evolution (TrEE) lab, Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, India 2. Queen Sirikit Botanic Garden, Botanic Garden Organisation, Chiang Mai, Thailand

Floral scents play a dual role in a plants fitness, that is as both an attractant as well as a deterrent. In a community, when congeneric species are in sympatry, competition drives interspecific variations in floral scents. Like any other morphological floral trait, floral scent profiles both qualitatively and quantitatively can be used as a taxonomic character, as they are key traits in many plant-animal interactions. These ecological interactions are often isolating mechanisms driving speciation in many mixed-floral communities. The chemical signatures from floral volatiles can also be used to differentiate taxa within species complexes. These are taxa where the members are not morphologically distinguishable. Here, we first explore the interspecific variations in floral scents among sympatric taxa and secondly, we explore chemicals that may act as signature molecules for taxonomic identifications. To address the above questions, we used the taxonomically complex, fragrant ginger genus Hedychium (Zingiberaceae) which is endemic to the Asian paleotropics. A total of 22 species and 12 intermediate forms were sampled from the NorthEast of India, Western Ghats, and Northern Thailand during two peak flowering seasons. The floral scents were extracted via dynamic headspace sampling and analyzed using Gas chromatography-mass spectrometry (GC-MS). The chemical analysis results revealed that most of the sampled sympatric taxa had their unique chemo space. The intermediates showed a shared profile from both the putative parents suggesting a congruence with what we had known from ecological and morphological data. Our work emphasizes the use of chemical data as critical and complementing to the morphological, ecological, and genetic data in drawing taxonomic boundaries. It also allows us to understand the ecological and evolutionary implications of floral scents among sympatric taxa.