Pollination ecology of Rauvolfia micrantha Hook. F. (Apocynaceae): a critically endangered medicinal plant from the southern Western Ghats.

摘要

The pollination ecology of Rauvolfia micrantha Hook. F., a critically endangered medicinal plant, was studied in the mountains of southern Western Ghats. The species has scanty distribution in the wild due to habitat degradation, fragmentation of population and narrow environmental niche. A comprehensive phenological investigation revealed that the plant flowers between March and October and the peak time of blooming period resides in May. Anthesis occurred from 0500 to 0830 hr with peak during 0700 hr. Anthers dehisced between 0600 and 1030 hr on the day of anthesis. Although the stigma becomes receptive one day before the opening of flowers, maximum receptivity (~70%) was recorded on the day of anthesis. Nearly 82% pollen grains were viable on the day of anthesis. The plants were self-incompatible and reproduced by means of cross-pollination, which enhanced the rate of fruit-set up to 80%; this strongly indicates the role of pollinators. The major insect pollinators included Apis florea (honeybee), Oecophylla smargadina (red ant), Trigona iridipennis (pollen bee) and butterflies such as Pachliopta aristolochaea, Pachliopta hector, Delias eucharis and Euploea core. The presented data will be of immense use for any rational strategy to conserve, multiply and genetically improve the species.