ISHS Acta Horticulturae 878: I International Orchid Symposium
ENVIRONMENTAL AND HORMONAL REGULATION OF FLOWERING IN PHALAENOPSIS ORCHIDS: A MINI REVIEW |
| Author: | E.S. Runkle |
| Keywords: | benzyladenine, cytokinins, gibberellic acid, light, potted plants, temperature |
| DOI: | 10.17660/ActaHortic.2010.878.32 |
| Abstract:
Phalaenopsis, Doritaenopsis, and their related hybrids are the most common commercially produced flowering potted orchids. Temperature regulates flower initiation and development of Phalaenopsis; inflorescence initiation (sometimes referred to as spiking) occurs in mature plants after at least 2 to 4 weeks of temperatures below 26°C under otherwise favorable conditions. Flowering of many hybrids is increasingly delayed as the daily duration at ≥28°C increases and can be completely suppressed with extended high-temperature exposure. Once an inflorescence has developed, time to open flower is a function of temperature and variety. Exogenous application of gibberellic acid (GA) can be used to increase inflorescence length, but more commonly, chemicals that inhibit the biosynthesis of active GA are used to suppress inflorescence elongation. In addition, cytokinins such as benzyladenine can increase inflorescence number of Phalaenopsis when applied near the onset of exposure to inductive temperatures. However, in some hybrids, inflorescences can develop abnormally if cytokinins are applied at an excessive rate or after flower initiation. Collectively, commercial producers of Phalaenopsis and their related hybrids can manipulate flowering by controlling temperature and applying chemicals that influence endogenous hormone levels to produce architecturally desirable and floriferous plants for predetermined market dates. | |
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