ABSTRACT
Terminalia arjuna is a deciduous tree widely distributed in tropical semi-evergreen and moist deciduous forests. Flowers of T. arjuna have ten stamens, which remain inside the bud and anthesis is carried out at different times of the day. Pollen grains are yellow in colour, medium and spherical, aperture is tri zonocolporate and exine is smooth. The pollen: ovule ratio is about 15,400 : 1. Optimum germination was seen in BBM + 12.5% sucrose. After 16 hr of anthesis, the pollen grains lost their viability and there was no fruit set. The current findings will be useful in studying pollen – pistil interactions, gene flow and heterozygosity of the T. arjuna populations.
ABSTRACT
Flowering phenology and reproductive biology of Rhynchosia beddomei, an endemic medicinal plant of Tirumala hills was studied in the natural habitat in the year 2010-11. Flowering was initiated in December 1st week and continued up to end of March. Peak flowering was observed in 4th week of December and another small peak was also observed in February 2nd week. The flowers are yellow in colour and are arranged in axillary or terminal recemes. Maximum pollen germination was observed in 12.5% sucrose solution + BBM at the time of anthesis (between12 noon to 12. 30PM) and in 37.5% concentration at 3.00PM. Maximum pollen viability was observed at 11.30 AM in TTC and FCR tests. Pollen tube growth was maximum in 12.5% sucrose with BBM at 11.30 AM. Pollen were lipid rich and starch poor. Predominance of outcrossing was observed and was brought about by insects, particularly bees.