Crocus sativus pollen germination and pollen tube growth in vitro and after intraspecific and interspecific pollination

The germination and tube growth of saffron (Crocus sativus L.) pollen were studied in vitro (in liquid media) and in vivo in pistils of Crocus sativus and Crocus thomasii after intraspecific and interspecific pollinations. In vitro about 20% of the saffron pollen grains germinated, but only about 9% developed a pollen tube. Although 21% of the pollen germinated on the stigmas, most pollen tubes ceased growth in the pistil and only a low percentage (about 6% of germinated grains) reached the ovary, where few of the ovules (about 5%) were penetrated. The defective germination and pollen tube growth were correlated with the occurrence of cytological abnormalities of the saffron pollen. Moreover, the ovarian transmitting tissue appeared to prevent the penetration of the ovules.