打顶时期对不同烤烟品种烘烤特性的影响

通过测定烤烟烟叶烘烤特性的相关指标，研究了打顶时期对烘烤特性的影响及品种间的差异。结果表明，适当推迟打顶能促进烟叶烤前和烘烤过程中叶绿素和类胡萝卜素的降解，降低含水量，提高失水速率，使丙二醛含量上升和多酚氧化酶活性降低，使烤后烟叶黄烟比例上升。烟叶易烤性和耐烤性均增加。但打顶时间过晚，烟叶质体色素含量过低，失水和衰老速度过快，使烟叶变黄失调，易出现黑糟烟，对改善烘烤特性不利。品种的差异是影响烟叶烘烤特性和确定打顶时间的重要因素。

Effects of Topping Stages on Tobacco Curing Characteristics in Different Flue-cured Tobacco Varieties

By examining the related indices of flue-cured tobacco curing properties, we studied the effect of topping time on the curing characteristics and the difference among varieties. The results showed that delaying topping could promote degradation of leaf chlorophyll and carotenoid before curing and during the process of curing, and decrease leaf moisture and increase water loss rate, increase malondialdehyde content and decrease polyphenol oxidase activity, and increase the proportion of yellow leaves after curing If topping was too late, tobacco plastid pigment content was too low, water loss and aging speed were too fast, thus causing imbalance of yellowing or black leave. Difference among variety was important factors which influenced curing characteristics and topping time.