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

Effects of spraying gibberellin and potassium nitrate on simultaneous maturation and quality of flue-cured tobacco upper leaves

【目的】为解决烤烟上部叶一次性采烤中出现的成熟状态差异大的问题,探究赤霉素、硝酸钾喷施浓度及喷施时间对烤烟中川208上部6片烟叶同步成熟、烤后烟叶质量的影响,以期为促进烤烟一次性采收提供理论依据。【方法】采用响应曲面优化设计中的Box-Behnken法,对赤霉素(0、15、30μmol/L)和硝酸钾(0、0.5、1.0 g/L)的浓度以及打顶后喷施时间(20、25、30 d)进行三因素三水平设计,共16个处理。测定从烟株顶部从上往下第1~3片烟叶(记为T上)和从上往下第4~6片烟叶(记为T下)成熟相关的生理指标,并计算各处理指标的同步成熟值,作为衡量同步成熟的依据,该值越小,说明同步成熟状态越好。【结果】各处理的同步成熟值明显小于对照,烤后烟叶外观质量、化学成分总分高于对照,以打顶后25 d喷施15μmol/L赤霉素和0.5 g/L硝酸钾(T2、T5、T9、T16)处理的同步成熟状态最好,外观质量总分、化学成分总分最高;响应曲面结果显示赤霉素、硝酸钾对综合得分具有极显著影响,且影响曲线相似,喷施时间对综合得分同样具有极显著性影响。模型验证及优化结果显示,烤后烟叶综合得分与预测值接近,说明所建模型可靠,能够预测烤后烟叶综合得分。【结论】喷施赤霉素和硝酸钾可促进上部叶的一致成熟,可提高烤后烟叶质量。

【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(0,15,30μmol/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 T up)and the 4-6 tobacco leaves from top to bottom(denoted as T down)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 15μmol/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.