The effect was studied of different day-length on the growth of 1st-, 2nd-, and 3rd-year-old seedlings of tulip grown under glasshouse. And on the one hand the optimum temperature on the growth of 1st-year-old seedlings was investigated too.
These investigation was based on the spposition that an acceleration in the succession of the yearly growth cycles results in a shortening of the duration of the juvenile phase.
1. The optimum temperature on the growth of 1st-year-old seedlings was convinced of near 15℃.
2. In the 1st-year-old seedlings the effect of temperature on the growth was more remarkable than of daylength.
3. The effect of daylength on the growth was alike in the 2nd- and 3rd-year-old seedlings.
i. e. (I) The appearance of the maximum growth period was influenced by the daylength and temperature, and was accelerated by short-day treatment more than by long-day.
(II) The growth rate was better long-day treatment than by short-day.
(III) It tended to retrain the formation of the 2nd stalk by the short-day treatment.
4. It appearad that in 2nd- and 3rd-year-old seedlings the growth under long-day length was better and bulbed successfully.