ABSTRACT
Ashoka Trust for Research in Ecology and the Environment, Royal Enclave, Srirampura, Jakkur Post, Bengaluru 560 064, India.
Email: shivanna@atree.org
Flowers are the units of sexual reproduction that involves a series of sequential events-production of functional pollen grains (male partners) and ovules (female partners), transfer of pollen grains from the anther to the stigma (pollination), pollen-pistil interaction leading to the entry of pollen tubes into the ovules and delivery of male gametes near the female gamete, fertilization, development of fruits and seeds, dispersal of seeds, and growth of seedlings into adults. Pollination is one of the most critical events in sexual reproduction of seed plants and plays a crucial role in both fundamental and applied aspects of reproductive biology. Pollination is the only means of gene fl ow between conspecifi c plants and populations, and is thus the basis of recombination. Successful pollination is a prerequisite for fruit and seed development, and thus plays an important role in reproductive success of both cultivated and wild plant species. Pollination limitation reduces the yield of cultivated species (Roubik 1995; Knight et al. 2005; James and Pitts-Singer 2008) and often acts as a driving force for species vulnerability in natural habitats (Spira 2001; Wilcock and Neiland 2002; Biesmeijer et al. 2006; Potts et al. 2009; Shivanna 2012a; Burkle et al. 2013; Tylianakis 2013). Information on pollination ecology is essential for the release of genetically transformed plants (Armstrong et al. 2005). Pollination services are needed to sustain pollinators particularly those that depend exclusively on fl oral resources (nectar/pollen).
