Morphology, Storage Behavior, Dormancy, Germination Pattern and Chemical Composition of Tabernaemontana pandacaqui Lam. Seeds

Background: Seed characteristics of Tabernaemontana pandacaqui Lam., an indigenous medicinal plant species from the Philippines, were investigated to help identify appropriate conservation strategies. Methods: Mature seeds were tested for viability at different dormancy-breaking treatments and storage conditions. Seeds were also characterized morphologically and the seedling developmental pattern was established using the Biologische Bundesanstalt, Bundessortenamt and CHemische Industrie (BBCH) scale. We also determined the preliminary chemical composition through qualitative phytochemical screening and proximate analysis. Result: Seeds of T. pandacaqui are obovate in shape with a 1000-seed weight of 20.99±0.62 g at 4.7% moisture content. Removal of the aril from the fresh seeds improved germination from 30%±0.98 to 84%±0.71 and shortened the time to seedling emergence from 45 days to 4 days after sowing. The seeds can tolerate drying to 4.7% moisture content and storage at -10°C for 3 months; thus, they have orthodox storage behavior. The germination pattern is epigeal phanerocotylar type, wherein the foliaceous cotyledons are raised (BBCH 09) and unfolded above the soil surface (BBCH 10). The seedling then develops an ovate to elliptic-shaped first true pair of leaves (BBCH 12) completing the germination process. The pre-dried seeds also have a high oil content of 28.7407±0.09316% with a strong presence of alkaloids and saponins. This indicates that the seed is amenable to ex-situ conservation through seedbanking, but its viability must be monitored in shorter intervals due to its high oil content.