抄録
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.
