Abstract
Observation on the flower bud differentiation and experiments on the effect of gibberellin on forcing in Bletilla striata REICHB. were carried out.
Initial primordia of tepals were observed on the 25th of August and pollens were formed on the 3rd of November in 1959 in Kagawa Prefecture (Table 1 and Fig. 1).
In order to examine the effect of gibberellin on forcing, four groups of bulbs were soaked in gibberellin of 50 ppm, 10 ppm, 1 ppm solutions and in water for 30 minutes, and then forced. These treatments and forcings were started on the 17th of November, the 1st and the 15th of December.
Growth_??_nd flowering of the plants were enhanced by gibberellin. Mean flowering dates of the plants treated with gibberellin of 50 ppm, 10 ppm and 1 ppm on the 17th of November were the 24th of December, the 29th of December and the 3rd of January respectively. This is 12 days earlier in the 50 ppm treatment than the control. The plants treated in later times were enhanced by gibberellin but the effects were less than those of the earlier treatments (Fig. 2 and 3).
From the results obtained, gibberellin treatment is effective for earlier forcing of Bletilla striata.
