Annual variation in floral phenology and pollen production in Lagerstroemia speciosa: an entomophilous tropical tree

• Main Author: Vinod Prasad Khanduri
• Format: Article
• Language: English
• Published: Prince of Songkla University 2014-08-01
• Series: Songklanakarin Journal of Science and Technology (SJST)
• Subjects: anthesis; pollination; pollen production; pollinators; floral display
• Online Access: http://rdo.psu.ac.th/sjstweb/journal/36-4/36-4-1.pdf

Flowering phenology and variation in total pollen production per tree in the natural population of Lagerstroemia speciosa was studied during four successive years, from 2006 to 2009. Reproductive phenophases were highly variable between years and individuals within population. Total flowering period lasts up to three months. Time of maximum anthesis was between 06:00 and 10:00 h of the day. On an average a flower took 2.5 to 3.0 hours for complete opening. Anther dehiscence occurred half an hour after anthesis. Apis spp. and Xylocopa spp. were observed the main pollinators. The visitation rates of pollinators varied from 0.62 to 2.82 visits/flower/hour with the average of 1.68±0.94 visits/flower/hour. Xylocopa bee shows physical fitness with flower morphology, which implies the functional relationship with regard to pollen transfer. There was alternate year production of flowers and pollen grains per tree. In the mass production years, a tree produces 6.4 x 108 and 1.3 x 109 pollen grains, which in poor production years oscillated between 4.2 x 107 and 5.4 x 107. 64% to 80% fruit set following open pollination in mass production year was estimated.