喷施赤霉素和硝酸钾对烤烟上部叶同步成熟和烤后质量的影响.

【Objective】To solve the problem of large differences in the maturity status of the upper leaves of flue-cured tobacco at one-time harvest, the present experiment explored the effects of gibberellin and potassium nitrate spraying concentration and spraying time on the simultaneous maturation and flue-cured tobacco quality of the upper 6 tobacco leaves of the flue-cured tobacco Zhongchuan 208. The impact was expected to provide a theoretical basis for promoting the one-time harvest of flue-cured tobacco. 【Method】Using the Box-Behnken method in response surface optimization design, the concentration of gibberellin (0, 15, 30 μmol/L) and potassium nitrate (0, 0.5, 1.0 g/L) and the spraying time (20, 25, 30 days) after topping was designed with three factors and three levels, a total of 16 treatments. The physiological indicators related to the maturation of the 1-3 tobacco leaves from top to bottom(denoted as Tup) and the 4-6 tobacco leaves from top to bottom(denoted as Tdown) were measured, and the treatment indexes were calculated. The synchronization maturity value was used as a basis for measuring synchronization maturity. The smaller the value, the better the synchronization maturity state. 【Result】 The synchronous maturity value of each treatment was significantly lower than that of the control, and the appearance quality and total chemical composition of cured tobacco leaf were higher than that of the control. The treatment of spraying 15 μmol/L gibberellin and 0.5 g/L potassium nitrate (T2, T5, T9, T16) had the best synchronous mature state, and the highest total score of appearance quality and chemical composition; The results of response surface showed that gibberellin and potassium nitrate had a very significant impact on the comprehensive score, and the impact curve was similar. The spraying time also had a very significant impact on the comprehensive score. The model validation and optimization results showed that the comprehensive score of flue-cured tobacco was close to the predicted value, indicating that the model was reliable and could predict the comprehensive score of flue-cured tobacco.【Conclusion】Spraying gibberellin and potassium nitrate can promote the uniform maturity of upper leaves and improve the quality of flue-cured tobacco leaves. [ABSTRACT FROM AUTHOR]