Abstract: It is one of the fundamental works for gene transformation and its ecosystem hazard evaluation to study the pollen characteristics of transgenic plants. In this research，some characteristics of pollen from seven- or eight-year-old transgenic plants of apple that carried exogenous CpTI gene were analyzed. The results showed that no signi ficant difference was found in terms of size，morphology，and exine ornamentation of the pollen in the transgenic plants compared to those in the non-transgenic control. It was found that transgenic plants had more abnormal pollen grains. Of the thirteen transgenic lines tested，12 lines had significant lower amount of pollen，and six exhibited significantly lower germination rate when cultured in vitro. The pollen viability of three transgenic lines was determined，of which two wassignificantly lower than that of the control. The transgenic Gala apple pollen grains germinated normally via controlled pollination on Fuji apple stigma. But the pollen tubes extended relatively slow during the middle and late developing stages，and another eight hours was needed to reach the ovules compared to the control. The concentration of gibberellic acid of the flower from transgenic Gala apple was lower than that of the non-transgenic control during all development stages tested. The concentration of abscisic acid in transgenic ones was lower during the pink stage and higher during the ball stage and full open stage. Microscopic observation of the anther structure showed no difference. The tapetum of the pollen sac wall in transgenic plants decomposed late，and affected the pollen grain development，which could be one of the reasons leading to the less of the pollen grain and the poor viability in transgenic plants.

Key words: apple, exogenous gene, pollen, viability, tapetum