Influence of the forms of nitrogen supplied on the growth of vegetable crops. VI
Effects of nitrogen forms on the concentrations of nitrogen fractions and carbohydrates in the plants
1969 Volume 38 Issue 4 Pages 309-317
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1969 Volume 38 Issue 4 Pages 309-317
Effects of nitrogen forms supplied on the growth, concentrations of nitrogen fractions and carbohydrates of cabbage and turnip were investigated in the solution or sand culture.
Growth of plants in the NO3 and the O3+NH4 treatments was the greatest, and growth of NH4 plants was the smallest, and that of urea plants was intermediate.
The tendencies of higher concentrations of total, insoluble and soluble organic nitrogen were observed in the NH4 and the NO3+NH4 treatments. However, such tendencies were not always found, when lower concentration of nitrogen was supplied. Higher concentration of nitrate nitrogen accumulated in the NO3 treatment, and more ammonium nitrogen was ound in the NH4 and the NO3+NH4 treatments. But, ammonium accumulation was much less than nitrate accumulation. In the urea treatment, lower concentrations of total, and insoluble nitrogen were found compared with those in the other treatments.
The concentrations of total, insoluble and nitrate nitrogen were higher at pH 7 than at pH 4 in cabbage leaves supplied with any forms of nitrogen. As for soluble organic nitrogen, the NO3 treatment was higher than the NH4 and the NO3+NH4 treatments at pH 4, on the other hand, at pH 7 vice versa. The concentration of ammonium nitrogen was somewhat higher at pH 7 than at pH 4 in the NH4 and the NO3+NH4 treatments.
The concentrations of reducing and total sugars in the leaves were higher in the urea, NH4 and NO3+NH4 treatments than in the NO3 treatment. As for the concentrations of non-reducing sugar and starch, there were no consistent tendency owing to forms of nitrogen supplied. On cabbage leaves, the concentrations of reducing and total sugars were higher at pH 4 than at pH 7 in the NH4 treatment, however, no differences of carbohydrate concentrations were found between pH 4 and pH 7 in the NO3 and NO3+NH4 treatments.
As for cabbage leaves, the concentrations of potassium, calcium, magnesium and sodium were the highest in the NO3 treatment, the lowest in the NH4 treatment, and intermediate in the NO3+NH4 and urea treatments. Similar tendency was observed with regards to pH of leaf sap. There was found no difference in the phosphorus concentration owing to forms of nitrogen supplied.
