Pollination Biology of medicinally important plant Leucas aspera
Prasad. E. R. and Sunojkumar P.
Leucas aspera Willd. (Lamiaceae) is an important and widely used medicinal plant. L. aspera started flowering from Middle of June ending in February. Detailed studies were carried out on the Phenology, floral biology, pollination and breeding system of L. aspera during 2011-2013 at Vythiri, Wayanad. Inflorescence initials are generally activated in the leaf axils. Flower opening in L. aspera began around 2.00 am and was completed around 3.00 am. Anther dehiscence began with a longitudinal slit appearing on the anther lobes at 3.00 am after opening the flower and the process was completed between 3.30-4.00 am. The main floral visitors were observed as Hymenopterans. The potential pollinators were recorded and calculated the % of visits for 2012 and 2013 respectively, A. dorsata (21.64 & 19.87), A. cerana (14.43 & 12.32), A. florea (13.4 & 11.3), Ceratina sp (18.6 & 22.6) and Ameigilla sp (16.5 & 16.5). The breeding experiment shows that manual cross pollinations using pollen from flowers of different plant resulted in 65% fruit set. In the open pollination in natural conditions resulted in 56.67% fruit set. Apomixis, flower bud bagged by removing stamens and stigma, resulted no fruit set. Our study concluded that the L. aspera was a cross pollinated species but absence of vector self-pollination were also found. The study clearly shown that cross-pollinated species has been shifting in to self- pollination.