title: Spectral effects of supplementary lighting on the secondary metabolites in roses, chrysanthemums, and campanulas.
abstract: To investigate the effect of the light spectrum on photosynthesis, growth, and secondary metabolites Rosa hybrida 'Scarlet', Chrysanthemum morifolium 'Coral Charm', and Campanula portenschlagiana 'BluOne' were grown at 24/18°C day/night temperature under purpose-built LED arrays yielding approximately 200 μmol m(-2)s(-1) at plant height for 16 h per day. The four light treatments were (1) 40% Blue/60% Red, (2) 20% Blue/80% Red, (3) 100% Red, and (4) 100% White (Control). The plant height was smallest in 40% Blue/60% Red in roses and chrysanthemums, while the biomass was smallest in the white control in roses and in 100% Red in chrysanthemums. The total biomass was unaffected by the spectrum in campanulas, while the leaf area was smallest in the 40% Blue/60% Red treatment. In 100% Red curled leaves and other morphological abnormalities were observed. Increasing the blue to red ratio increased the stomatal conductance though net photosynthesis was unaffected, indicating excess stomatal conductance in some treatments. With higher blue light ratio all phenolic acids and flavonoids increased. In view of the roles of these secondary metabolites as antioxidants, anti-pathogens, and light protectants, we hypothesize that blue light may predispose plants to better cope with stress.
authors.affiliation: Department of Chemical Engineering, Biotechnology, and Environmental Technology, University of Southern Denmark, Niels Bohrs Allé 1, Odense, Denmark. Electronic address: tou@kbm.sdu.dk.
authors.forename: Theoharis
authors.initials: T
authors.lastname: Ouzounis
authors.affiliation: Department of Chemical Engineering, Biotechnology, and Environmental Technology, University of Southern Denmark, Niels Bohrs Allé 1, Odense, Denmark.
authors.forename: Xavier
authors.initials: X
authors.lastname: Fretté
authors.affiliation: Plant and Environmental Sciences, Selection for Crop Sciences, University of Copenhagen, Hoejbakkegaard Alle 9, DK-2630 Taastrup, Denmark.
authors.forename: Eva
authors.initials: E
authors.lastname: Rosenqvist
authors.affiliation: Department of Food Science, Aarhus University, Kirstinebjergvej 10, 5792 Aarslev, Denmark.
authors.forename: Carl-Otto
authors.initials: CO
authors.lastname: Ottosen
mesh_terms: D029422:Campanulaceae / Q000033:anatomy & histology / Q000378:metabolism / Q000528:radiation effects*; D002851:Chromatography, High Pressure Liquid; D031202:Chrysanthemum / Q000033:anatomy & histology / Q000378:metabolism / Q000528:radiation effects*; D005419:Flavonoids / Q000378:metabolism; D008027:Light; D010636:Phenols / Q000378:metabolism; D010788:Photosynthesis; D018515:Plant Leaves / Q000378:metabolism; D027826:Rosa / Q000033:anatomy & histology / Q000378:metabolism / Q000528:radiation effects*
chemical_list: D005419:Flavonoids; D010636:Phenols
keywords: Light-emitting diodes; Ornamental plants; Photosynthesis; Secondary metabolites; Stomatal conductance