贵州烤烟上部叶烘烤特性研究

Study on the Curing Characteristics of Flue-cured Tobacco Upper Leaves in Guizhou

为进一步明确烤烟烘烤特性和优化散叶烘烤工艺，以毕纳1号和贵烟2号上部叶为材料，研究散叶烘烤过程中烟叶水分含量、叶片形态、电导率值、质体色素含量、SPAD值的变化以及烟叶变黄程度。结果表明：烘烤过程中烟叶水分含量、叶长、叶宽、叶面积、叶绿素含量、SPAD值呈逐渐减小的趋势，而电导率值基本上呈逐渐增加的趋势，类胡萝b素含量呈先降低后略有升高的趋势。38℃时，贵烟2号水分含量显著高于毕纳1号；48—54℃时，两者的水分含量降幅值均最大；42—48℃时，两者的叶片长度和宽度收缩均较大；贵烟2号烘烤过程中叶片纵向、横向和叶面积收缩率均较大，其中，叶面积收缩率显著大于毕纳1号。毕纳1号和贵烟2号烟叶绝对电导率和相对电导率的最大增幅值分别出现于38～42℃和48～54℃；其中，38℃时，贵烟2号烟叶相对电导率值显著大于毕纳1号；54℃时，贵烟2号绝对电导率和相对电导率值均显著大于毕纳1号。毕纳1号和贵烟2号叶绿素、类胡萝卜素含量及SPAD值在鲜样至38℃间降幅值最大；与贵烟2号相比，毕纳1号38℃前变黄较快，38℃后变黄相对较慢。相对于毕纳1号，贵烟2号较易烘烤，而电导率值、叶绿素含量和SPAD值均可作为烟叶烘烤特性的判断指标。

In order to further optimize loose leaves bulk curing technology and make a clear curing characteristics of different flue-cured tobacco genotypes （ Bina 1 and Guiyan 2）, the changes of the water content, leaf morphology, electrical conductivity value, plastid pigments content, SPAD value and yellowing degree of upper tobacco leaves were studied during loose leaves bulk curing. The results showed that water content, leaf length and leaf width, leaf area, chlorophyll content and SPAD value gradually reduced, and conductivity value increased gradually while carotenoids content reduced first, then rose slightly of different flue-cured tobacco genotypes during loose leaves curing. At 38 ℃, Guiy- an 2 had a higher water content than Bina 1 ; at the range of 48 ℃ to 54 ℃, both Bina 1 and Guiyan 2 had the biggest value of the decreasing amplitude of water content. Leaf length and leaf width changed greatly at the range of 42 ℃ to 48 ℃ ; compared with Bina 1, Guiyan 2 had a larger longitu- dinal shrinkage ratio, transverse shrinkage ratio and leaf area shrinkage ratio （P 〉 0. 05 ）, especially for leaf area shrinkage ratio （ P 〈 0.05 ）. Absolute conductivity and relative conductivity of Bina 1 had the biggest increasing amplitude at the range of 38 ℃ to 42 ℃ during curing while Guiyan 2 had the biggest increasing amplitude at the range of 48 ℃ to 54 ℃ during curing. However, relative con- ductivity of Guiyan 2 was significant higher than Bina 1 at 38 ℃ （P 〈 0.05 ）, and absolute conductiv- ity and relative conductivity of Guiyan 2 were significant higher than Bina 1 at 54 ℃ （P 〈 0. 05 ）. Chlorophyll content, carotenoids content and SPAD value of the Bina 1 and Guiyan 2 had the biggest decreasing amplitude at the range of fresh to 38 ℃ during curing. Bina 1 was yellowing faster than Guiyan 2 before 38 ℃, but then lower than it. Compared with Bina 1, Guiyan 2 had a better easy curing. And conductivity value, chlorophyll content and SPAD value all can be used as indexes for judging tobacco curing characteristics.