Abstract: Effects of removal of the shoot apex and leaf wounding on nitrogen uptake and nicotine production were studied with tobacco plants grown in sand or hydroponic medium under the controlled conditions.The results showed that removal of the shoot apex resulted in significant increase in nicotine concentration in different organs and whole tobacco plants.Leaf wounding also increased nicotine concentration in tobacco leaves,and the increment caused by wounding twice was more than that caused by once.However,the effects on nicotine production caused by leaf wounding were smaller than that caused by removing the shoot apex.Removal of the shoot apex and leaf wounding did not show any influences on nitrogen uptake by plant,but increased nicotine production per unit nitrogen.The results demonstrated that mechanical wounding stimulates nicotine production,and the increase in nicotine production was not correlated with nitrogen taken up by roots.