The Pollination Mechanism in Balanophora abbreviata Blume

Abstract

In spite of extensive studies on the mechanism of pollination in flowering plants, very little is known in this respect of the tropical root-parasites belonging to Balanophoraceae. The only recorded observation on pollination in the family is that of Moore (1940) who did not examine the mechanism involved but correlated the emission of heavy perfume to the visit of small flies in Dactylanthus. As there is no literature on pollination in the genus Balcknophora (Kuijt, 1969), the present study was undertaken. Balcuzophora abbreviata is an obligate, reduced, achlorophyllous fleshy root-parasite which grows on Acacia suma Buch. Ham. and Pithecolobium duke Beath. along the banks of the river Cauvery at Ranganathittu near Mysore city, South India. The taxon is charac¬terized by a monoecious inflorescence bearing 20-40 male flowers in the lower region and innumerable archegonia-like female flowers protected by spadicles in the upper part (Plate IA). Each male flower has a synandrium with 15-20 anther sacs enclosed usually by four perianth lobes. During anthesis, the wall of the anther sacs abutting the perianth lobes breaks down. As a consequence the pollen mass comes into direct contact with the perianth lobes. The perianth lobes open early in the morning, once only, and present the 1 sticky pollen to the pollinator. The spherical pollen grains have spinulate exine with 8-12 circular pores. As the male flowers start opening, the slender stylar processes of the female flowers emerge between the spadicels imparting a velvety surface to the capitulum. Further, the spadicles secrete a sugary liquid which collects as small droplets on the surface of the female part of the inflorescence simulating dew drops.