抄録
Effects of artificial illumination on Japanese iris (Iris Kaempferi) were examined.
It failed to flower when put under artificial illumination from September 1, but it flowered when treated from October 1. It seemed that Japanese iris required some period of short days before the beginning of illumination for its flowering. Then, four lots were prepared and each lot would be illuminated from Sept. 1 to April 1 next year. The 1st lot was kept on short day conditions from Oct. 1 to Oct. 10 when artificial illumination was discontinued. In the same manner illumination of the 2nd lot was discontinued from Oct. 1 to Oct. 20 and illumination of the 3rd lot was discontinued from Oct. 1 to Oct. 30. The 4th lot was not given any short photoperiod until this experiment was finished.
As a result the 1 st, 2rd and the 3rd lots flowered, but the 4th lot failed to flower.
In addition to the formal experiment, two more trials were prepared. Plants which were used for the 1st experiment were kept on long day conditions from Sept. 1 last year to May 31 and didn't flower. Then short day treatment was given for 15 and 30 days from June 1. These plants flowered in August.
Plants which were used for the 2nd experiment were kept on long days from Sept. 1 last year.
Illumination of these plants was discontinued on March 31, April 30 and May 31. As a result the plants where illumination was discontinued on March 31 and April 30 flowered in August, but those where illumination was discontinued on May 31 failed to flower.
It seemed that the blooming in August was because of exposure to natural short day periods in spring after the illumination had been discontinued on March 31 and April 30. And it was because of no exposure to short photoperiod that the plants where illumination was discontinued on May 31 failed to flower.
