Studies On Mutual Relations Among Mineral Nutrients In Tobacco

By means of water culture and laboratory analysis, this paper studied the effects of nitrogen, ammonium/nitrate, potassium, calcium, magnesium, ion strength and pH of different levels on the absorption and accumulation of mineral nutrients by flue-cured tobacco variety NC.89. And the interactions among the nutrient ions were also discussed. The results were as follows:1. The growth and the accumulation of dry matter in tobacco closely associated with the concentrations of nutrient ions in culture solution. Under the condition that the forms and concentrations of other nutrients keep the same in the culture solution, Tobacco grew and changed as parabola curves with the increasing of nitrogen, potassium, calcium and magnesium respectively. The concentrations of nitrogen, potassium, calcium and magnesium, respectively to get the maximum growth and day matter accumulated in tobacco plant were not consistent. The situations in the tobacco root, stem and leaves were similar to that in the whole plant. The influences of poor supply of nitrogen, potassium, calcium and magnesium were greater than that of excess supply. The tobacco growth was closely relate to the forms of nitrogen in the solution. Tobacco grew best when supplied nitrate nitrogen while at NH4+/NO3~ 3:7 the root grew the best. The biomasses of tobacco were different in solutions with different ambient pH. Tobacco grew best at pH 6.5. The ion strength of the culture solution also affected tobacco growing and dry mass accumulation.2. The accumulation and absorption of the other elements were influenced by the single change of N, K, Ca, Mg, ion intensity and pH when other conditions were the same. Generally, when the contents of N, K, Ca, Mg was lower, the absorption of nutrient could be helped with the increasing of nutrient contents, however, when the contents were higher, the results were to the contrary and inhabited tobacco grown. The changing law of root, stem and leaf was consistent basically with the total plant.3. The accumulation of nutrients changed like parabola curves by the singlechange of the supply levels of N, K, Ca and Mg intensity and pH when other conditions were the same, but it different for different nutrients. The form of nitrogen was closely related to the accumulation amount of nutrient of tobacco in the solution. Generally, with the proportion of nitrogen of solution increasing, the accumulation of N, P, Ca and Zn changed like parabola curves. However, it is different for the proportion of niter-nitrogen. The accumulation of K, Mg, Cu, and Mn rose with the increasing of niter-nitrogen while the range was different. The accumulation of N, P, K, Ca, Mg, Zn and Cu changed like parabola curves with the increasing of pH. But pH was different when accumulation was maximum. The relationships between Mn accumulation and pH were complicated, and the Mn accumulation was reduced first and then increased lightly, again was reduced. The nutrient accumulation changed like parabola curves when ion intensity changed from low to high in solution, however, the ion intensity of max-accumulation appearing were not inconsistent.