To determine if expression AtHSP101 in pollen affects pollen viability and growth, we examined pollen germination rate and pollen tube elongation of transgenic tobacco GS2, GS7 and GS17 lines and compared the results with those of wild-type SR1 and a null GS3 line. No difference in pollen germination rate was observed among SR1 (Fig 5A), transgenic (Fig 5B) and null (Fig 5C) lines under optimal temperature condition. Nevertheless, noticeable variations in the degree of pollen tube elongation were observed among these lines (Figs 5A–5C and 6). Comparing with SR1 WT, the pollen tube elongation in GS3 null line was slightly reduced (Figs. 5C and 6). Conversely, transgenic lines such as GS2, GS7, and GS17 had much vigorous pollen tube growth under control conditions with a doubling of tube lengths compared to the SR1 control (Figs. 5B and 6). The enhancement of pollen tube growth was observed in all transgenic lines examined under normal conditions.