Studies on in-vitro pollen germination of holmskioldia sanguinea retz

Holmskioldia sanguinea Retz., a small garden tree under Verbenaceae, flowers during November to January. Flowers generally open in 07:00hrs-10:00hrs and anther dehiscence takes place simultaneously. The effect of different compounds on in vitro pollen germination of Holmskioldia sanguinea showed that, the pollen grains start to germinate in distilled water and 2% sucrose solution enhanced germination (97%) as well as tube length (624µm). Individually, 500ppm boric acid (H3BO3) showed 88% pollen germination with a pollen tube length of 555µm. It was also recorded that, maximum 98% pollen germination with tube length of 656µm developed in 2% sucrose solution supplemented with 500ppm boric acid. Among the salts, maximum 47%pollen germination occurred in 100ppm Ca(NO3)2 solution with 351µm pollen tube length while 44% pollen germination along with 195µm pollen tube length in 500ppm KNO3 solution and 11% pollen germination with 208µm long tube developed in 200ppm solution of MgSO4. The pollen grains of the flowers which were collected during anthesis showed the best result.