Effects of topping and NAA application on potassium accumulation and redistribution in flue-cured tobacco

[Objective]The effects of topping and NAA application on potassium absorption, accumulation, as well as the re-distribution of flue-cured tobacco were studied in order to provide theoretical references for regulating nutrition and quality of flue-cured tobacco. [Method]This study was carried out at different stages of tobacco developments along side with pot experiments and different treatments (topping, apex-keeping, and NAA) on tobacco plants. [Result]The results showed that topping accelerated dry matter accumulation of tobacco leaf, stem, and root, increased the potassium content in root as well as the middle leaves and stem at earlier stage of tobacco, but decreased that of upper leaves, middle leaves,and stem at later stage. It could also promote the potassium accumulation in leaves, stem, root, and its distribution in leaves. The bioavailability rate of potassium decreased, but the economic utilization rate of potassium in tobacco plants increased. After topping, the application of exogenous NAA could significantly increase the accumulation of potassium in tobacco plants, potassium content in middle leaves at earlier stage, and the contents in roots at later stage, while decrease potassium content in the upper leaves and stem; furthermore, the application of exogenous NAA could increase potassium accumulation in leaf, stem, and root, promote potassium distribution in tobacco leaves, and increase the economic utilization and bioavailability rates of potassium in tobacco plant. [Conclusion]The application of exogenous NAA after topping could balance different endogenous hormones, increase potassium accumulation in tobacco leaves, promote the absorption and redistribution of potassium, and improve the leaf quality.