|Authors: ||L. Zheng, M.C. Van Labeke|
|Keywords: ||light emitting diode, light quality, stomata, chlorophyll fluorescence kinetic|
Combined with multilayer system, apply LED light in specific production phase of ornamentals makes it possible to study the effects of light quality on its physiological performance and plant-water relations.
As plants will continue their growth in the in a drastic changing greenhouse environmental afterwards.
In this study, Pelargonium zonale, Cordyline australis and Ficus benjamina were selected and grown under four light qualities: white (W, 420-700 nm), blue (B, 460 nm), red (R, 660 nm) and 50% blue + 50% red LED (RB) with light intensity at 100 Ámol m-2 s-1. Effects of light quality on parameters related to photosynthesis (chlorophyll, CF parameters) and plant water relations (stomatal density, stomatal conductance) were studied.
We found no general effect of light quality on pigment biosynthesis of the studied species.
In Pelargonium zonale, the highest chlorophyll content was obtained under W and the lowest under B, while for Cordyline australis, the highest content was found under RB and the lowest under R, for Ficus benjamina not effect of light quality was found.
Chlorophyll fluorescence kinetic parameters showed similar trends for the three ornamentals.
The quantum yield as well as the photochemical quenching was highest under B or RB while lowest values were found under R. Light quality also affected leaf stomatal density and conductance though effects were species dependent. Cordyline australis had the highest stomatal density under W while no effect of light quality was found for Pelargonium zonale the highest stomatal conductance was found under B.
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