Preliminary Study on the Relationship between Degraded Rules of Chromoplast Pigments and Carbohydrate in Upper Leaves of Hunan Flue-cured Tobacco

The relationship between the degraded rules of chromoplast pigments and carbohydrate in upper leaves of flue-cured tobacco after topping was studied by using tobacco variety K326. The results showed that: Degradation of chromoplast pigments in upper leaves occurred mainly in 30-45 days after topping. The average drop in this stage of chlorophyll and carotenoids content were 47.16% and 58.10%. The total sugar content decreased from the day of topping to the following 15 days, then it increased and tended to be stable. But the starch content increased for 30 days after topping, then decreased. Grey incidence analysis indicated that: the closest correlation to total sugar in late-growth stages were the ratio of carotenoids/chlorophyll (0 and 15 days after topping) and the carotenoids (30 and 45 days after topping), whereas the starch showed that the closest correlation were the chlorophyll a (0 days after topping) and total chlorophyll (15 days after topping), then were the ratio of carotenoids/chlorophyll (30 and 45 days after topping).