Germination capacity and viability of stored pollen in two ornamental species of the genus caesalpinia L. (caesalpini oideae-fabaceae) and their maintenance

Pollen germination capacity and viability of two species viz., Caesalpinia gellisii (Hook.) Dietr. and Caesalpinia pulcherrima (L.) Swartz. of the family Fabaceae were examined up to 48 weeks. Viability was determined on the basis of germination ability of pollen on sucrose medium with boric acid solution. Fresh pollen were stored at different storage conditions including refrigerator (4°C), freezer (-20°C, -30°C), freeze drier (-60°C), vacuum chamber and organic solvents. Pollen stored at low temperature -60°C showed better germination as compared to pollen stored at 4°C and fresh. C. pulcherrima showed much better germination percentage at -60°C (61.00%) whereas, C. gellisii, showed 30.80% germination after 48 weeks of storage. Pollen stored over silica gel in vacuum of both the species showed good germination as compared to organic solvents. Freezer (-20ºC and -30ºC) and freeze dryer (-60ºC) maintained pollen germination capacity and viability for a longer period as compared to fresh, refrigerated, pollen treated in vacuum over silica gel and organic solvents. Conclusively both low temperature and RH humidity are the most influential factors in controlling germination and viability of pollen grains. (author)