Abstract
Some effects of two kinds of long day treatments on the growth of Abies Sachalinensis seedlings were tested for about 12 months by sand culture with five kinds of solutions containing mineral nutrients(Table.1).
Supplementary light for long day treatments was given by the fluorescent lamps (about 1, 000 lux) for four hours (from 5 to 9 p.m.) and for seven hours (from 5 to 12 p. m.) every day.
Experimental results are shown in Figs.1 to 3, and Table 2. Under long day treatments, growth of seedlings was accelerated with all kinds of nutrient solutions, especially more in stem than in root.
The effect of long day was the most remarkable with the 2 × standard solution in which long day seedlings were about 2.6 times of control plants(natural day length) indry weight. And it decreased in the following order; 2×N, 2×P, 2×K, and standard (Table 2).
Four hours a day of supplementary illumiation seemed to be more effective in the following three solutions; 2 X standard, 2×N, and 2×P.
It should be noticeable, however, that long day seedlings had a tendency to develop for k-shaped lateral shoots on their tops in consequence of faster growth of their lateral buds and to form irregular shapes (Fig.2).
