Dynamic change in mineral elements and nicotine content of burley tobacco during plant growth and development

Burley tobacco variety “Dabai 1” was used to investigate dynamic changes in mineral elements and nicotine content of tobacco during growth and development at different altitudes. The results show that N content increases before topping, while it decreases after topping. P content remains stable during the whole growth period. K content decreases with growth, but rapidly decreases after topping. The content of micro-elements in tobacco is in the following order: Ca > Mg > Mn > Fe > Zn > B > Cu. Ca, Mg, Mn and Zn increase at early growth stages, and then decrease. Fe and Cu steadily decrease, while B remains stable. N, Ca and Mg are lower in tobacco cultivated in high altitudes than that in low altitude. P, K, Fe and Mn are higher in high altitude tobacco than in low altitude tobacco. All the other elements remain unchanged. Ca, Mg and B are low irrespective of altitude, while Cu and Fe are abundant. Nicotine is higher in low altitude tobacco than that in high altitude tobacco, higher in top leaves than in middle leaves, and increases significantly after topping