| This experiment was conducted to study Yunyan85, a variety of flue-cured tobacco, by determining starch contents and amylase activities of fresh leaves of all stalk positions of tobacco plants in the field and leaves of all stalk positions under different flue curing temperatures and different maturities, testing starch contents of cured leaves of different treatments, then variance and correlativity analyzing between starch contents and amylase activities. The results indicated that starch contents of fresh leaves of all stalk positions increases gradually with the increasing of growing days. At the same growing period, starch contents of fresh leaves of different stalk positions increase gradually from bottom to top. During the flue curing period, starch contents of leaves of different treatments is reducing gradually and starch degrades in a large amount within the first 36-48 hours after flue curing began, then the degradation rate tended to slow. Amylase activities of leaves of different treatments reached its highest level at 36-48 hours after flue curing began, then began to decrease, and increased to some extent at the end of flue curing. Variance analysis results showed that different maturities and different flue curing temperatures have remarkable effect on starch contents of tobacco leaves. Foot, middle and upper leaves got the lowest starch contents and best usability in the treatment of low flue curing temperature and normal maturity. Lower leaves got the lowest starch contents and best usability in the treatment of normal flue curing temperature and still maturity while top leaves in the treatment of low flue curing temperature and over maturity. Correlativity analyzing results showed that starch degradation had extremely remarkable positive correlation with amylase activity within the first 36 hours after flue curing began. It meant that starch degradation increased with the increasing of the amylase activity. |
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