Influence Of Different Light Intensity On Quality And Organization Structure Of Tobacco Seedlings And Quality Of The Flue-cured Tobacco

In order to explore the effects of light conditions and different quality tobacco seedlings on the agronomic traits,physiological and biochemical indexes and physicochemical properties of flue-cured tobacco leaves,the different lighting conditions are designed with artificial light source of indoor and used tobacco varieties of Yunyan 87 and K326 as floating seedling materials.The effects of different light conditions on the growth and tissue structure of tobacco seedlings are studied and agronomic traits,physiological and biochemical indexes of tobacco plants and physicochemical properties of flue-cured tobacco leaves surveyed when the different quality tobacco seedlings were transplanted to field.After statistical analysis and tissue section observation,the following study results were obtained.:(1)When the light hours are above 6h,the effect of light intensity on the growth of tobacco seedlings is greater than that of light hours,and the light intensity have a greater impact on leaf width,stem circumference,chlorophyll,total soluble sugar content and root activity of tobacco seedlings.However,the change of light intensity has little effect on the carotenoid content of leaves.When the light hour is 9h and the light intensity reaches 8000 Lux,it can promote the rapid growth of tobacco seedlings to reach the requirements of strong seedlings with stem height of 11 cm,stem circumference of 1.8cm and forming seedling stage is in80 d.(2)When the lighting hours is the same,increasing the light intensity can promote the development of leaf vein vascular bundles and the density increase of palisade tissue,and promote the development of vascular bundles of tobacco seedlings roots in the stroma layer.However,the effect on the development of tissue structure and growth under the water root system are less than it above stroma layer when lighting hours and intensity changed.(3)Strong seedling transplanting is beneficial to the growth of tobacco plants for Yunyan87 and K326 in field,especially effecting greatly on the stem circumference of tobacco plants,little on the plant height and maximum leaf width of tobacco plants in the rosette stage;It also has a great influence on the plant height and the maximum leaf length and leaf width during the flower budding stage.The results of physical and chemical properties of flue-cured tobacco indicate that quality of tobacco seedlings has little effect on the relative water content,stalk rate and thickness of middle and upper flue-cured tobacco leaves,and has a greater influence on leaf length and width.The chloride ion content in the middle andupper flue-cured tobacco leaves is closely related to the quality of the tobacco seedlings.The worse the quality of tobacco seedlings,the higher the chloride ion content of the flue-cured tobacco leaves.The better the quality of the tobacco seedlings,the lower the chloride ion content of flue-cured tobacco leaves.