Studies of the Effects of Nitrogenous Fertilizers on the Photoperiodic Responses of Rice Plants : Especially on the C/N-Ratio of Dry Tissue Powder and on the Osmotic Pressure, Specific Electric Conductivity and Relative Viscosity of the Expressed Sap

摘要

Photoperiodic treatments were given to the rice plants of material at their earlier stages of growth continuously for 50 days. The main results are as follows : The heading in the short-day plot occurred about 35 days earlier, and the heading in the long-day plot 4 days later, than that in the natural-day plot. Insufficient supply of nitrogen promoted heading slightly in the short-day plot, while the same retarded it in the natural-day-length plot and in the long-day plot. In the short-day plot, the values of C/N-ratio, osmotic pressure, specific electric conductvity and of the relative viscosity increased earlier, while the water content of plant tissues decreased earlier, than in the other plots. In both the natural-day plot and the long-day plot, those above mentioed values (except the water content) of the plot without nitrogen-fertilizers were higher than those in the plot with nitrogen applied July. 17th. The relation became reversed, however, when the fertilizers were applied Sept. 21th.