Study On Improving The Quality Of Upper Leaves Of Flue-cured Tobacco

To solve the problems that the upper flue-cured tobacco leaves are thick and their chemical composition is not harmonious and theirindustrial usability is not enough,the growing development of tobacco was regulated and controlled in the later land stage and the baking technology was improved in this experiment based on traditional field managing skills such as generalizing fine seed and protecting soil and reducing nitrogen and increasing planting density and early transplanting and so on to establish an integrated skill system that improves the usability of upper tobacco leaves to make the quality of upper tobacco leaves meet the requirements of tobacco industry and offer the theory support and technology guidance of the production of quality tobacco leaves.The main conclusions are as follows.1.Different topping time and topping ways boss had evident effect on the quality of upper tobacco leaves.The maturity is good and the content of nicotine and the total nitrogen is lower while the content of total sugar and reducing sugar is higher and the proportion of sugar of nicotine is better when topping time is between the first blooming and half middle flowers are blooming.The bagging and no topping skills can promote the growth of tobacco leaves in early stage,however,this would lead the mass growth of sidesprout and had some bad effect on the growth and maturity of tobacco leaves in middle and later stage.So,the regular topping and when topping time is between the first blooming and half middle flowers are blooming does best to promote the usability of upper tobacco leaves.The appearance features of upper tobacco leaves after such dealing is that half of each leaves turned white and the angle of leaves and stem was almost right angle and each leaves was arciferal pectoral girdle and few parts of tip and edge of leaves scorched.2.Applying gibberellic acid after topping did good to the diastole of upper tobacco leaves.The content of SPAD reduced and the content of total nitrogen reduced after curing as well,however,the content of sugar and reducing sugar increased and the proportion of K and Cl got harmony.Applying 500mg/L ethephon after harvesting the lower and middle tobacco leaves did good to the diastole of upper tobacco leaves.The content of SPAD reduced and the total nitrogen and K and Cl had no clear change,the content of reducing sugar increased in some extent and the proportion of sugar and nicotine got harmony.We can conclude that gibberellins and ethephon could boss promote the usability and improve the physical and chemical character of tobacco leaves.3.Ring cutting and root hurting after harvesting the lower and middle tobacco leaves could evidently slow down the growth and reduce the thickness of upper leaves.The treatments made SPAD got less and the upper leaves turner yellowish green,the construction got loose,the oil got less and the maturity improved clearly,the total sugar and reducing sugar got higher,the total nitrogen and nicotine reduced,the content of K and Cl changed little.We could conclude that ring cutting and root hurting could evidently promote the maturity and balance the chemical component of upper tobacco leaves.4.The content of chemical component got best while the upper tobacco leaves got complete mature,at this time,the total nitrogen and nicotine reduced while the total sugar and reducing sugar increased,the proportion of sugar and nicotine got harmony.The content of chemical component changed little if tobacco leaves were cured with stems and the total nitrogen increased while the proportion of sugar and nicotine did not change in this treatment.This showed that harvesting with stem had no effect on the chemical component of cured upper tobacco leaves.