In tobacco, in vitro pollination has been successfully applied to overcome interspecific incompatibility. The use of this technique will make it possible to introduce DNA into pollen tubes just before fertilization. In this study, we showed improvement of the efficiency of in vitro self-pollination and introduction of foreign genes into pollen tubes by the method of polycation. A plasmid harbouring the GUS gene was introduced into pollen grains and pollen tubes, which had incubated on pollen germination medium(PGM), by polyornithine method. Transient expression of the GUS in pollen grains and pollen tubes that were treated with 0, 2, 5 and 10μg/ml DNA was observed. In results, combination of the techniques of polyornithine and in vitro pollination was efficient new technique for genetic transformation through fertilization processes.

Palynological characters such as pollen grain polar axis length (PL), pollen equatorial diameter (ED), colpus length, colpus width, and P/E ratio of six species of Quercus subgenus Lepidobalanus Endl. from Korea were studied. A significant interspecific variation, unequal distances between the species, and various degree of intraspecific variations were found. The taxonomic value of the pollen morphology parameters measured was found to vary according to species. These results suggest a possible relationship between parameters measured and ploidy level of the Quercus species studied.