Abstract
Flax plants (var. Saginow No. 1) were grown in pots under different day length (8. 12, 14.and 16 hours). The length of the plants became longer in long days, and the flowering was promoted by the long days. However, in the short day the growth of the plant was restrained and the flowering was delayed. The number and growth of the basal branch sprouted from dicotyledonal axile increased in the short day. The long day condition increased the yield of the fibers and enlarged the diameter of the fiber cells, but the cell wall thickness of the fiber cells became larger in the plants cultivated in short day such as 8 hours. The fibers of better quality were obtained in the short day, for their fibers contained larger quantity of α-cellulose than those in the long days such as 12, 14, or 16 hours. However, in the short day such as 8 hours the lignin contents became larger than those in the longer day length plots.
