Effects Of Nitrogen On Growth And Form Of Quality Of Sun-Cured Red Tobacco

The effects of nitrogen rates,ratio of nitrogen,phosphorus and potassiumand fertilization rates of organic nitrogen on accumulation and distribution of the drymatter and nicotine and macroelements uptake and distribution in sun-cured redtobacco plant and physiological characteritics and chlorophyll fluorescencecharacteristics of leaf and the content of nitrate and nitrite and chemical componentsand smoking quality of the cured leaves were studied in pot and field experimentsduring 2002-2003.At the same time,the optimal method of fertilization aboutproduction of the high quality sun-cured red tobacco leaves was evaluated.The resultswere as follows.1.With the raise of N application rates,the accumulation of the dry matter took on acontinuously increasing trend during the whole growth period.The distribution rate ofleaf dry matter were higher in early stage and later showed a slow trend and had nosignificant diference in rosette stage,but it showed a decreasing trend with the raise ofN application rates from fast growing stage.The distribution ratio of stalk dry matterwas very low before rosette stage,rapidly increasing from rosette stage to fast growingstage.The distribution ratio of root dry matter was steadily increasing as tobaccogrowth stages were pushing on.At the same nitrogen rate,absence of P and K wouldresult in metabolism maladjustment of tobacco plant and finally affectedaccumulation of the dry matter.Increasing P and K rates could made for increasingroot/shoot ratio of tobacco plant.The results showed that the accumulation of the drymatter of plant and the distribution ratio of stalk and root dry matter and the yield ofcured leaves could increase when the ratio of organic nitrogen was 25%-50%.2.With the raise of N rates,the chrolophyll content,NR and INV activity and Fv/Foand Fv/Fm ratio of tobacco fresh leaves all presented a gradually increasingtrend.Nitrogeng surplus would make NR activity of tobacco fresh leaves decrease atthe rosette stage.Nitrogen deficiency and nitrogeng surplus both could decrease theNR/INV ratio.It showed that nitrogen deficiency and nitrogen surplus could restrictthe level of nitrogen metabolism in early stage.At the same N applicationgrate,absence of P and K would decrease NR activity and Fv/Fo and Fv/Fm of tobaccofresh leaves.The results showed that properly increasing nutrient could increase 70...