Reproductive biology of Kannanthali [Exacum bicolor (Roxb.)]; An endangered, potential native ornamental of the lateritic hillocks of Kerala
Keywords:
Exacum bicolor, pollination, floral biology, pollen viability, stigma receptivityAbstract
Exacum bicolor (Roxb.) is an herbaceous perennial endemic to peninsular India and enlisted as an endangeredplant species. Since a thorough insight into the reproductive biology of a species is necessary to aidconservation and crop improvement, the present study was formulated to assess the floral biology andreproductive behaviour of the plant. It was found that the bisexual flowers of this plant possess pollen grainsthat remain viable for nine days after anthesis exhibiting maximum viability on the first day of anthesis(84.61%) and 84.18 per cent viability on the previous day of anthesis. Stigma was found to be receptive uptofour days after anthesis. Maximum seed weight per capsule (17.21 mg) was realised from flowers pollinatedon the third day of flower opening. There was 100 per cent fruit set in flowers that were open pollinated aswell as in the flowers which were either controlled out-crossed or self-pollinated under control. Fruit setwas not observed on bagging the flowers to avoid natural out-crossing, and on open pollination. Hence, itbecame evident that Exacum bicolor (Roxb.) is primarily a cross-pollinated species, although no selfincompatibility mechanism operates in the species. Also, natural self-pollination is not favoured forprocreation; reproduction via apomixis is absent in the species.References
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