How plants flower in response to different light conditions.

摘要

The effects of light quality, day length duration and light intensity on flowering is complex and the current removal of the incandescent bulb from the market is problematic for commercial greenhouse production especially of species which flower in long days (LD). The photoreceptors involved include Phytochrome, the Cryptochromes and photosynthetic pigments. For LD species the role for Phytochrome involves Far Red (FR) wavebands activating expression of two genes involved in floral signalling, a GA 20-oxidase which is critical in the synthesis of the gibberellin (GA) plant hormones and the FT gene. In addition, any photosynthetic increase in LD directly activates FT expression. Acting independently of FT, there may also be a weaker direct response to the Daily Light Integral via changes in photosynthate supply. Such information allows accurate predictions of the effect on flowering of a range of glasshouse lighting. A current challenge is to match this knowledge to lamp type availability especially given the ongoing improvements in lamp design/energy efficiency and in light filtering techniques.