Constituents of autotoxic chemical from rhizosphere soil underfluecured tobacco continuous cropping

The rhizosphere soil under fluecured tobacco continuous cropping for 12 years was used to estimate the autotoxic potential and constituents of autotoxic chemicals for disclosing the development mechanism of successive cropping obstacle of tobacco. The results of this study showed that the continuous cropping encouraged the tobacco rhizosphere soil to produce greatly autotoxic potential to lettuce and tobacco seedlings when compared to control. 7 carbohydrate compounds, 14 acid compounds, 16 ester compounds, and only one the other compound were found in the control soil, but 2 carbohydrate compounds, 3 acid compounds, 8 ester compounds, and 12 other compound were identified in the tobacco rhizosphere soil with continuous cropping for 12 years. Comparing to control, 8 kinds of chemical compounds in the tobacco rhizosphere soil were involved in autotoxic potential, and they were vanillin, digitoxin, cedrol, pentadecanone, tricosene, sitosterol, cholestanol, and Cholestan3one.