キャベツの収量および遊離糖含量に及ぼす培養液中の窒素, リンおよびカリウムの影響

Abstract

Cabbage plants were grown for about 2 months in a culture solution containing 3 levels of nitrogen (5, 50, 500ppm), phosphorus (2, 20, 200ppm) and potassium (5, 50, 500ppm), and effects of the supply on head yield and free sugar composition of the plants were studied.Plant dry weight and head yield increased with the increase of N (5-50ppm), P (2-20ppm) and K (5-50ppm) in the culture solution, and decreased at the highest level of each element. Nitrogen, phosphorus and potassium contents in plants increased greatly with the increase of levels of each element. Fructose, glucose and sucrose contents of plants decreased with the increase of nitrogen levels, and the decrease of sucrose was great. In the phosphorus and potassium treatment, fructose and glucose contents did not change remarkably but sucrose content was the highest at 20ppm of P and at 50ppm of K. Fructose content was higher in head leaves than in outer leaves. There was close correlation between head yield and sucrose content in the outer leaves in all treatments with the exception that 5ppm N. Nitrogen deficiency caused an increase of free sugar content, especially of sucrose.