关键词: 评估, 评估

Abstract: To study the formation of tobacco aroma style in different ecological zones, we chose flue- cured tobacco‘K326’which was planted in three different ecological zones (Yunnan, Fujian and Henan) as the test sample. The first sampling was processed after 70 days from tobacco transplanting by collecting mature leaf in 7th position. Then after every 12 days, we collected mature tobacco leaves in position #10, #13, and #16 successively. δ¹³C value, photosynthetic pigment and chemical constituents variation of tobacco leaves were analyzed in our experiments. The results showed that δ¹³C value with chlorophyll a/b and carotenoids content with chlorophyll were negatively correlated. The δ¹³C value of Fujian and Yunnan had significant negative correlation with the total chlorophyll a and chlorophyll (P＜0.05). The δ¹³C values of Henan had weak positive correlation with chlorophyll carotenoids ratio and chlorophyll a/b ratio. The same value in Fujian and Yunnan were positively correlated to chlorophyll and carotenoids ratio, while negatively correlated to the chlorophyll a/b ratio. In Fujian and Yunnan chlorophyll a content, chlorophyll b content, overall chlorophyll content and carotenoid content (except leaves in position 13th) had no significant differences (P＞0.05). The average δ¹³C value was positively correlated to nicotine, nitrogen and potassium, and had weak negative correlation with total sugar, reducing sugar and chlorine. Intuitive comparison of total sugar, reducing sugar, nitrogen and potassium among samples from three areas showed that Henan’s was significantly different from Fujian’s and Yunnan’s, while no obvious difference was found between Fujian’s and Yunnan’s. As to δ¹³C value, Henan’s was the minimum (the average value of four leaf position was -29.67‰), which was significantly different from Fujian’s (-26.32‰) and Yunnan’s (-25.6‰). Meanwhile the value was not significantly different between samples from Fujian and Yunnan. Generally speaking, the δ¹³C values were different among regions, not only changed roughly identical with photosynthetic pigment content, but also had similar trends with chemical composition. δ¹³C value, photosynthetic pigment and chemical composition of tobacco leaf from three different regions had different styles. This conclusion provided idea that using δ¹³C as threshold we could determine planting districts of tobaccos with different aroma style.