While the authors have previously developed a method of pistil filament treatment with Agrobacterium cells during blossoming for the transformation of maize generative cells, the mechanism for bacterial T-DNA penetration into the embryo sac remained unknown. This article analyzes the possibility of agrobacterial penetration into the maize embryo via pollen tubes. Microbiological, PCR, and GUS techniques were used to confirm that agrobacteria could spread for up to 20 cm from the sie of inoculation and were detected in maize embryo tissues as aerly as 24 h after inoculation, while they were not revealed after 5-13 days.