[Objective]To adjust the initial concentrations of nitrogen in the seedling pool under the condition of floating seedling system,and to promote the growth and development of tobacco seedlings in Southern Anhui Province.[Method]With normal application of nutrient as CK,initial concentrations of nitrogen was desgined as 150,200 and 250 mg/kg. The growth and physiological characteristics of tobacco seedlings were detected under different concentrations.[Result] Within the designed range,enhancing the initial n...