Changes of Thickness and Dissecting Structure of Upper Leaves of Flue-cured Tobacco during Curing

The upper leaves of flue-cured tobacco cv.NC89, K326, RG11 were sliced, and their changes of thickness and dissecting structure were observed from the stages of yellowing to color fixing.The results showed that the dissecting structure change happened mainly during the process from the stage of yellowing to the earlier stage of color fixing, and the "susceptive time" varied with varieties;the change of leaf thickness relied on the changes of sponge and palisade tissue during curing;the changes of thickness and dissecting structure were related to color fixing rate.It is a must to take tobacco character into account while curing upper leaves, control the key curing stage by adopting proper technology of yellowing and color fixing to make cured leaves thinner.