Study On The Relationship Between Harvesting, Flue-curing And Quality Of Tobacco Leaf

In this article, the changing law of many enzymes and pigment in tobacco leaf during different mature periods were investigated, the changing law of physiological biochemistry were investigated during different yellowing temperatures, yellowing humidities, yellowing times. The appearance quality, chemical composition, economic character, smoking quality in tobacco leaf with different mature periods, harvesting manners and curing conditions were studied. The results as follows:As the maturity degree increased, the degree of yellowing in tobacco leaves raised gradually, the content of pigment were decreased , the maturity degree were increased approximately 10 percent with harvesting time postponing 5~7 days.In this experiment, the activities of SOD, POD were declined comparatively in tobacco leaves at different positions,(excepting cutters) duing maturity. The content of MDA were increased gradually,t he activities of the poly phenol oxidase and diastase was decreased at first and increased subsequently during maturity. The peak of starch content appeares with 60～70 percent yellowing, 80～90 percent yellowing, 90～100 percent yellowing in lower, middle, upper leaves, then the starch was transformed.The changes of total sugar and reducing sugar was complex and was not obvious rule too during maturity. the content of total nitrogen and protein were decreased slowly in tobacco leaves at different positions, the content of nicotine was decreased at first and increased subsequently in lower and upper leaves,but the content of nicotine was increased continuously.Among them, with the activities of diastase and the content of starch, pigmentas as the index of judgementing tobacco leaves maturity to a certain extent, but the activities of PPO, some protectiase and the content of MDA, sugar as the index of judgementing tobacco leaves maturity beneficial supplement.The physiological biochemistry, economic characteristics, chemical...