The variation of volatile compounds emitted from aromatic orchid (Phalaenopsis bellina) at different timing and flowering stages

Abstract

Phalaenopsis bellina, is an orchid widely known for their distinctive fragrance. Of late, fragrant orchids are getting more attention from Orchid breeders for their horticultural market value. Although volatile compounds have been identified in several orchid species, the floral scent emission of P. bellina is far from understood. Therefore, this study was carried out to investigate the influence of different timing and floral development stages on the volatile emissions from P. bellina flowers using Solid Phase Micro Extraction (SPME) and Gas Chromatography-Mass Spectrometry (GC-MS). The volatile compound was extracted during morning and afternoon sessions from three different floral developmental stages. The volatile compounds emitted from flowers from two different sessions were trapped with SPME fiber for 30 minutes before directly injected into GC-MS for identification. Results showed that approximately 79 volatile compounds were identified, with the terpenoid presented as the major compound class. P. bellina had the highest number of volatiles during the morning and full bloom (41), with 29.82% monoterpene and 23.33% sesquiterpenes accounted in total. α-farnesene (19.56%) was abundance during morning emission and remains as the highest volatile in afternoon emission (44.08%), even higher when compared to morning emission. However, a decrease in the volatile compound was observed in afternoon emission, in which only 34 volatile compounds detected. Meanwhile, partial bloom developmental stage revealed linalool as the major terpenoid volatile compounds (25.89%), with only 20 volatile compounds recorded. On the other hand, no volatile compounds were recorded and profiled from flower bud stage. The establishment of a floral scent study provides a brief overview of the regulation of fragrance in P. bellina, which can be continued through gene isolation or fragrance-related enzymes study. This information will provide necessary information on orchid floral scent research that useful in boosting horticultural trade of the scented orchids and their function in pollination ecology study