EFFECTS OF LEDS ON CHLOROPHYLL FLUORESCENCE AND SECONDARY METABOLITES IN PHALAENOPSIS
Light emitting diodes (LEDs) are solid-state semiconductor devices that have been integrated in current greenhouse systems the last decades as they provide the opportunity to control light spectrum. Commercial production of potted orchids under LEDs has increased throughout the world the past decades with Phalaenopsis being one of the most valuable potted crops. The experiment took place from January to April 2013 using plantlets of Phalaenopsis Vivien and Purple star. Plants were grown under a purpose-built LED array from Philips yielding approximately 200 µmol/m2·s at plant height for 16 h per day. The temperature in the greenhouse compartments was set to 24/18°C day/night, respectively. The three light treatments were (1) 40% Blue 60% Red, (2) 100% Red, and (3) 100% White (Control). The plants were harvested before flowering and plant growth was recorded at the end of the experiment. Chlorophyll fluorescence was also recorded with PAM-2001. Leaf area and total fresh weight were highest in the 40%B/60%R for Phalaenopsis Vivien, while 100%R demonstrated the highest leaf area and fresh weight for Phalaenopsis Purple star. Chlorophyll fluorescence for the same treatments was a little higher when compared to the control. Quantitation of secondary metabolites was performed by HPLC. The analysis showed that the treatments with additional blue light had the highest amount of flavonoids and carotenoids.
Ouzounis, T., Fretté, X., Rosenqvist, E. and Ottosen, C.O. (2015). EFFECTS OF LEDS ON CHLOROPHYLL FLUORESCENCE AND SECONDARY METABOLITES IN PHALAENOPSIS. Acta Hortic. 1078, 87-92
carotenoids, flavonoids, light emitting diodes, orchids