施氮量和留叶数对烤烟LY1306上部叶生理特性及产质量的影响

Effects of Nitrogen Application Rate and Retained Leaf Number on Physiological Characteristics,Yield and Quality of Upper Leaves of Flue-Cured Tobacco LY1306

为确定烤烟新品系LY1306的最佳氮用量与留叶数组合,进一步提高烟叶品质,本试验采用双因素裂区设计,以氮素用量(N)为主区、留叶数(L)为副区并均设3个水平(N:22.5、37.5、52.5 kg/hm^(2);留叶数:22、24、26片/株),研究两者及其互作对烤烟上部叶叶面积、碳氮代谢关键酶活性、光合特性和烤后烟叶质量及经济性状的影响。结果表明,施氮量、留叶数及其互作对烤烟上部叶叶面积、碳氮代谢酶活性、叶绿素含量和净光合速率影响显著,施氮量和留叶数的合理组合有利于LY1306上部叶开片,成熟过程中也能保持合理的碳氮代谢强度和光合速率。3个留叶水平下,烟叶产量以及总氮、烟碱含量均以高氮处理最高,产值和钾含量则以中氮处理最高;3个施氮水平下,烟叶产量及上部叶总糖和还原糖含量均以高留叶水平最高,产值和上等烟比例则以中留叶水平最高。中性香味物质含量则随着施氮量和留叶数的增加呈先升后降趋势,以施氮量37.5 kg/hm^(2)和单株留叶24片处理组合最高。综之,施氮量37.5 kg/hm^(2)和单株留叶24片可以提高LY1306烤后烟叶的等级结构,改善上部叶品质,增加经济效益。

In order to find the optimal combination of nitrogen rate and number of retained leaves for the new flue-cured tobacco strain LY1306,and further improve the quality of tobacco leaves,this experiment adopted a two-factor split zone design.Nitrogen dosage(N)was the main zone and the number of retained leaves(L)was the secondary zone,and three levels were set(N:22.5,37.5,52.5 kg/hm^(2);number of retained leaves:22,24,26 leaves per plant).Their effects and their interaction on upper leaf area,key enzyme activities of carbon and nitrogen metabolism,photosynthetic characteristics,tobacco quality and economic characters of flue-cured tobacco leaves were studied.The results showed that the nitrogen application rate,the number of retained leaves and their interactions had significant effects on the upper leaf area,carbon and nitrogen metabolism enzyme activity,chlorophyll content and net photosynthetic rate of flue-cured tobacco.The reasonable combination of nitrogen application rate and the number of remained leaves was beneficial to the opening of the upper leaves of LY1306,and could maintain reasonable carbon and nitrogen metabolism intensity and photosynthetic rate during the ripening process.Under the three levels of leaf retention,tobacco yield,total nitrogen and nicotine contents were the highest under high nitrogen rate,while output value and potassium content were the highest under medium nitrogen rate.Under the three levels of nitrogen application,tobacco yield and total sugar and reducing sugar contents in upper leaves were the highest at high leaf retention level,while output value and proportion of fine tobacco were the highest at medium leaf retention level.The content of neutral aroma substances increased first and then decreased with the increase of nitrogen application rate and the number of retained leaves,and the highest value was found under the treatment with nitrogen application rate at 37.5 kg/hm^(2)and 24 retained leaves per plant.In summary,the combination of 37.5 kg/hm^(2)of nitrogen application rate and 24 retained leaves per plant could improve the grade structure of LY1306 flue-cured tobacco leaves,quality of upper leaves and economic benefits.