Plant photoreceptor absorption as a quantitative measure for plant photomorphogenic characteristics of incident spectra

Higher plants alter their morphology in response to incident spectra as their specific compositions directly and indirectly indicate specific environmental conditions.
These responses are evolutionarily developed under sunlight to best adapt to changing environments.
As the emission spectra of electrical lightings are substantially different from that of sunlight, photomorphogenic responses of plants under electrical lightings can be anomalous.
However, method to quantitatively represent such characteristics of incident spectra is not available to date.
Here we present that the absolute quantity of light absorbed by each of major photoreceptors can be used to quantitatively represent the plant photomorphogenic characteristics of incident spectra.
We developed a method to normalize and represent photoreceptor absorptions.
Artificial solar and three different light sources with identical photoreceptor absorptions were developed using conventional light sources such as high-pressure sodium lamp, fluorescent lamp, light-emitting diodes, and incandescent lamps, of which exhibited substantially different spectra.
Then cucumber (Cucumis sativus L.) plants were grown under the developed light sources and their morphology, photosynthesis, and growth were compared.
Results clearly showed that the morphology of cucumber plants grown under the same photoreceptor absorptions showed indistinguishable photomorphogenesis despite of their substantially different spectra.
The plants grown under conventional light sources showed shorter stem and internode length, steeper leaf angle, and reduced growth which are consistent to previous reports.
We conclude that the absolute quantity of light absorption of photoreceptors can be used as a quantitative measure for photomorphogenic characteristics of incident spectra with robustness and reproducibility.

XXX International Horticultural Congress IHC2018: III International Symposium on Innovation and New Technologies in Protected Cultivation

W.H. Kang, J.W. Kim, J.E. Son

electrical lighting, light spectrum, photomorphogenesis, plant factory, vertical farming

https://doi.org/10.17660/ActaHortic.2020.1271.30