1991 Volume 60 Issue 3 Pages 651-657
The timing of flower stalk emergence and the onset and duration of flowering of hybrid juvenile (3-yr-old) and adult (6-yr-old) white-flowered Phalaenopsis plants as affected by an 8-hr day, natural daylength, and two temperatures and growing under varying light intensities were evaluated. The experiments were conducted in a growth chamber, greenhouse, and outdoors from July to late October. The short day trials lasted for 55 days.
1. The 8-hr day advanced the emergence of flower stalks by 5 to 7 days in juvenile and adult plants held at 23°C as compared to those held under natural daylength (1986). Some plants held at 28°C produced stalks but they did not bear flowers.
2. Short days advanced the date of flowering of both juvenile and adult plants at 23° and 22°C in 1986 and 1987, respectively. At 28°C, no flowers were initiated.
3. Plants grown under 8-hr day had longer stalks and tended to have more flowers than those grown under natural daylength.
4. Most flower stalks were borne at the fourth and fifth nodes below the uppermost leaf node.