Flowering Biology and Palynology in Drumstick (Moringa oleifera Lam.)

Study for a calendar year on bearing plants of drumstick grown in the humid tropics of South India revealed that flowering was throughout the year except in the months of November and December. Flowering peaked during July-August and February-March. The peak fruit production was during July-August and March-April. The flower buds were grouped into seven stages based on size. Flower buds took 29.8 days or 472.25 degree days from initiation to complete their development during rainy season. In summer season it was 24.8 days or 471.18 degree days. The pollen grains of drumstick were spherical with smooth exine and had three germpores. The average diameter of fertile and sterile pollen grains was 43.Sµm and 33 µm respectively. The average pollen production per anther in rainy and summer seasons was 7 250 and 7 500 respectively. Pollen grains exhibited · highest germination and tube growth in JS per cent sucrose medium. Viability on acetocarmine staining and germination was 97 and 88 per cent respectively. Pollen grains stored under refrigerator lost their viability only after seven days while under ambient conditions it lost viability within three days.