Effects of high temperature and plant growth regulators on vegetative growth and flowering of potted orchids
Linsey Newton and Erik S. Runkle
Thesis, Master of Science (Horticulture), Michigan State University. 159 pages. 2008.
2008
บทคัดย่อ
Phalaenopsis, the most popular potted orchid, is induced to flower when the day temperature is ≤26 °C. Four Phalaenopsis clones were exposed to 29 °C for 0, 4, 8, 12, or 24 h per day with the remaining hours of the day at 20 °C to determine how high day temperature duration influenced flowering. Phalaenopsis 'Explosion' and 'Mosella' required exposure to 29 °C for 8 h, while Phalaenopsis Baldan's Kaleidoscope 'Golden Treasure' and Doritaenopsis Newberry Parfait required exposure to 29 °C for 12 h, to delay or prevent inflorescence initiation. A second study investigated the use of repeated benzyladenine (BA) sprays to increase vegetative growth or flowering of Paphiopedilum, Miltoniopsis , and Odontoglossum hybrids. BA at 800 mg·L-1 increased shoot number of large Paphiopedilum in Year 1, but higher concentrations were not effective in Year 2. In Year 2, applications of 4,000 mg·L-1 BA increased the number of new vegetative shoots formed on medium-sized Paphiopedilum and on two clones of young Miltoniopsis . A third experiment determined the efficacy of applications of 15, 30, or 45 mg·L-1 paclobutrazol to inhibit inflorescence elongation of three Phalaenopsis clones with tall inflorescences. Paclobutrazol applications inhibited inflorescence length of Phalaenopsis 'Andrew' by 19% to 23% compared to control plants but had no statistical effect on two other hybrids. A spray application made after flower initiation caused an undesirable clustering of the flowers whereas earlier sprays did not.