供镁水平对烤烟生长及养分吸收的影响

采用盆栽土培试验研究了不同供镁水平对烤烟生长和养分吸收的影响。结果表明，施MgSO4量为0.06～1.08 g/kg时，各处理烤烟的生长状况和干物质积累量明显优于对照和施MgSO4 1.88 g/kg。烤烟各器官对钾的吸收最多，氮次之，磷最少，各处理表现一致。施MgSO4量为0.18～0.72 g/kg的3个处理烤烟各器官对氮磷钾的吸收量明显高于其他处理，且在施MgSO4量为0.36 g/kg时达到峰值。当施MgSO4量较低（≤0.06 g/kg）或较高（MgSO4≥1.08 g/kg）时都会抑制烤烟的生长发育、干物质和养分的积累。而烤烟各器官对镁的吸收量则均表现出随施镁量增加而增加的趋势，且各器官镁吸收量表现为:叶＞茎＞根；镁肥的施用能够在一定程度上促进烤烟对镁素的吸收。

Effects of magnesium nutrition on growth and nutrient absorption of flue-cured tobacco

Magnesium is an essential element in biological systems of flue-cured tabacco. A pot culture experiment was conducted to investigate the effects of different magnesium nutrition levels on the growth and nutrient absorption of flue-cured tobacco. The results showed that: compared to control, application of Mg significantly promote the growth status and enhance the dry matter accumulation of flue-cured tobacco as the magnesium application rate was 0.06–1.08g/kg. The uptake of K2O was the highest, followed by N, and the lowest was P2O5 in different tobacco organs for all magnesium treatments. The uptake of N, P2O5 and K2O of different tobacco organs with Mg application rate being 0.18–0.72 g/kg was significantly higher than the other treatments. The highest uptake of N, P2O5 and K2O was observed as the Mg application rate was 0.36g/kg. Both magnesium deficit (MgSO4≤0.06 g/kg) or magnesium surplus (MgSO4≥1.08 g/kg) restrained the growth, accumulation of dry matter and nutrient uptake of tobacco. Magnesium uptake in different organs of tobacco increased with the increasing of magnesium application rate for all treatments. The application of magnesium fertilizer can promote magnesium uptake of flue-cured tobacco.