Isolation of two populations of sperm cells from the pollen tube of Torenia fournieri.

The two sperm cells of Torenia fournieri are dimorphic. The dimorphic character suggests that they might be preferentially involved in fertilization during in vivo fusion with the egg cell and central cell. To probe the mechanism of preferential fertilization, it is necessary to use the most current molecular techniques. For this purpose, populations of >1000 individuals of the two dimorphic sperm cells, Sua (unassociated with the vegetative nucleus) and Svn (associated with the vegetative nucleus) were isolated from pollen tubes that had grown out of the cut ends of the styles. The two sperm cells released from pollen tubes remained attached to one another. When the two attached sperm cells were transferred into a solution containing 0.01% cellulose, 0.01% pectinase, and 5% mannitol, the connection between the two cells disappeared, and they were easily separated using a micromanipulator. The collection of these two individual populations containing over a thousand cells will permit research on gametic recognition at the molecular level.