Abstract: Northern blot analyses revealed there is a homologue of Atdad1 in tobacco and the expression is more in leaf and flower.But with the senescence of leaf,the expression reduced gradually.Using transgenic tobacco with 35S-Atdad1,we studied the connection of Atdad1 and apoptosis.The results showed 48℃ heat 4 hours or 75 ng/mL actinomycin D treat 48 hours caused the normal cell apoptosis,but under the same condition,the transgenic cell showed no change.And during the process of apoptosis of normal cell,the expression of dad1 reduced step by step.