Abstract
In the present investigation particular attention was given to a study of the influences of the concentrations and the sorts of sugars upon the tuber formation of potato stem segments cultured under sterile condition. Potato of the variety "Irish Cobbler" was used as material. When the potato stem segments were cultured in the syntheic medium containing low concentration of sucrose, such as 2% and 4%, the growth of lateral buds arising from the stem segments was recognized, but there resulted no tuber formation. On the other hand, by the cultures with high concentrations of sucrose as 6%, 8% and 10%, the tuber formation occurred at the tips of lateral buds of the stem segments and, at the same time the rate of tuber formation was accelerated in proportion to the increase of sucrose concentration in the medium. The effects of maltose, glucose, and fructose on the tuber formation were similar to that of sucrose. Judging from the results described above, it may be assumed that the tuber formation on the potato stem segments under the sterile culture is closely related to the amount of sugar added to the culture medium.
