Abstract: explore the reasons for the varied aroma among 3 kinds of flue\|cured tobaccos cultivated in different soil types in Nanxiong， namely purple soil， sandy paddy soil and cows liver soil， the tissue structure during plant growth， contents of major alkaloids and routine compounds in the middle leaves of flue\|cured tobacco Yueyan 98 were compared. It was shown that the palisade tissue of tobacco cultivated in purple soil became thicker earlier than the others. The palisade tissue thickened fast first and then turned slowly for tobaccos in sandy paddy soil. Tobaccos grown in cows liver soil showed the highest thickness of palisade tissue， sponge tissue and leaf at maturity， although the increase initiated rather late. In the flue\|cured tobacco leaves （C3F）， the content of total sugar and reducing sugar decreased as the order sandy paddy soil > cows liver soil > purple soil， while the ratio of sugar to nicotine was the contrary. Tobaccos in sandy paddy soil possessed the highest anatabine content and the lowest anabasine， while， the highest nornicotine content and the lowest anatabine was shown in tobaccos in cows liver soil. Compared with the others， tobaccos cultivated in purple soil exhibited the lowest nornicotine yet the highest anabasine and the nicotine content， and therefore was suitable for the production of flue\|cured tobacco with strong fragrance.

Key words: flue\|cured tobacco, tissue structure, alkaloids, chemical composition