In vitro germination of western larch pollen

We have been able to successfully germinate western larch (Larix occidentalis Nutt.) pollen in vitro. Pollen was rehydrated at 100% RH for 16 h before being sprinkled on semisolid and liquid media. The basic medium contained Brewbaker and Kwack minerals diluted 1:10 and was supplemented with polyethylene glycol 4000 and three different concentrations of sucrose. The flavonol quercetin was also included in half of the media. More pollen grains survived on liquid media, but semisolid media gave superior germination results. Two to 9% of the grains produced tubes. Quercetin had no major effect on germination, viability, or tube length.