Reproductive Biology of Acacia nilotica (L.) Willd. ex Del. subsp. indica Benth

The reproductive biology of Acacia nilotica (L.) Willd. ex Del. subsp. indica Benth. (Mimosaceae) is detailed by floral biology, phenology, pollen biology, stigma receptivity,breeding system, composition and relative abundance of flower visitors, time spent at flowers by pollinators and resource allocation. The percentage of pollen viability varied significantly (P<0.05) from 50% to 75%. The morning samples collected between 10.00 and 11.00 hours had significantly better viability (75 %) than the samples collected at 17.00 hour (50 %). 8% sucrose supplemented with boric acid 1000 ppm and gibberellic acid 500 ppm was found to be an ideal medium for enhanced pollen germination and pollen tube growth. The viability of pollen stored at 0°C was highest in comparison to the pollen kept at room temperature and at 4°C. A total of 17 flower visitors recorded in the study sites. Oxyrchis torandus had spent maximum time on flowers. The construction of each flower costed 0.00416 g, of these 48% of total allocation spent by attractive yellow colored stamens. The seed cost recorded as 44% of the total pod cost, while remaining 56% allocated to pack the seeds as well as to organize for effective dispersal.