Abstract: Taking tobacco variety K326 as the test material, under hydroponic conditions, the effects of five phosphorus concentrations of 0, 0.5, 1.0, 2.0, 4.0 mmol/L (calculated as P₂O₅) on the growth, relative conductivity, antioxidant capacity, plastid pigment content and absorption of main nutrient elements of flue-cured tobacco seedlings were explored. The results showed that phosphorus concentration significantly affected the nutrient absorption, growth and development of flue-cured tobacco. With the increase of phosphorus concentration, the growth of tobacco seedlings first increased and then tended to be stable; the relative conductivity and antioxidant capacity first decreased and then increased; the plastid pigment content and the content of main nutrient elements in tobacco leaves first increased and then decreased. When the phosphorus concentration was 2.0 mmol/L, the contents of lutein, chlorophyll a, chlorophyll b and carotenoids were the highest, and the contents of total nitrogen, total phosphorus, total potassium, total calcium and total magnesium in tobacco leaves also reached the highest. This indicated that appropriate phosphorus application was helpful to improve the nutrient absorption efficiency of flue-cured tobacco seedlings, enhance their stress resistance, and alleviate environmental stress, and the concentration of P₂O₅ at 2.0 mmol/L had the best effect on the nutrient uptake of flue-cured tobacco.

Key words: phosphorus level, flue-cured tobacco, growth, nutrient absorption, antioxidant capacity