Studies on the reproductive strategies of sapota (Manilkara zapota)

Abstract

Aim M. zapota is inadequately known with respect toits reproductive strategy and functional specialization which are crucial aspects in determining its reproductive success. The present investigation was conducted to study the role of floral traits in pollinator recruitment pollinators' involvement in selection of floral traits and strategies of plants to ensure pollination services. Methodology Fifteen-year-old trees of sapota (var. Kalipatti) were taken as an experimental material. Floral characters like floral morphology, anthesis, pollen dehiscence, stigma receptivity, pollen production were studied by tagging twenty flowering branches distributed across ten plants. Pollination efficiency was also studied. The relation between parameters was worked out through simple linear regression equation. Results Flowers were characterized by small aperture, floral chamber, long spell of stigma receptivity (48 hrs), imperceptible nectar secretion, high pollen cwule ratio (980:1) and self-compatibility. The peak stigma receptivity was between 07:00 - 10:00 hr on the day of anthesis. On the basis of visitation rate (3.0-5.5/flower) and pollination efficiency (13.85 - 17.87%) thrips were considered as primary pollinators and Silvancpsis sp. (beetle) as a co- pdlinator. Presence of narrow aperture, floral chamber and imperceptible secretion of nectar make the flowers of sapota fictionally specialized. Interpretation Floral traits like narrow flower aperture played a crucial rde in filtering specific visitors (thrips and beetle) to access floral rewards. Moreover, the morphological adaptation like floral chamber facilitated better pollen services by providing shelter and breeding place for pollinators.