Investigating the merit of including far-red radiation in the production of ornamental seedlings grown under sole-source lighting

Y. Park, E. S. Runkle

Research output: Chapter in Book/Report/Conference proceedingChapter

7 Scopus citations

Abstract

A combination of red (R; 600 to 700 nm) and blue (B; 400 to 500 nm) lightemitting diodes (LEDs) is commonly used in sole-source lighting of plants grown in highly controlled environments. R and far-red radiation (FR; 700 to 800 nm) regulate photomorphogenesis, including stem elongation and leaf expansion, and to some extent, photosynthesis. However, little research has been published on how FR LEDs can be used to improve plant growth and quality attributes during seedling production. We grew seedlings of snapdragon (Antirrhinum majus) at 20°C under six sole-source LED treatments with an 18-h photoperiod. All treatments included 32 μmol m-2 s-1 of B radiation (peak = 451 nm) and different intensities (subscript in μmol m-2 s-1) from R (peak = 660 nm) and FR (peak = 729 nm) LEDs: R128, R128+FR16, R128+FR32, R128+FR64, R96+FR32, and R64+FR64. Plant height and total leaf area linearly increased as the R:FR or the estimated phytochrome photoequilibrium of each treatment decreased. Shoot dry weight was similar under the same total photon flux (400 to 800 nm) even when R radiation was partially substituted with FR (considered minimally photosynthetic) and linearly increased when R was constant and FR increased. Photosynthetic efficiency (PE), which is calculated as shoot dry weight per unit leaf area, was correlated positively with the calculated yield photon flux of each +FR treatment. In addition, PE linearly decreased as the amount of R was increasingly substituted with FR radiation. We conclude that supplementation of FR to R and B radiation can increase PE and subsequent dry mass accumulation without excessive leaf and stem expansion.

Original languageEnglish (US)
Title of host publication8th International Symposium on Light in Horticulture
EditorsR.G. Lopez, E.S. Runkle, C.J. Currey
PublisherInternational Society for Horticultural Science
Pages259-265
Number of pages7
ISBN (Electronic)9789462611092
DOIs
StatePublished - May 22 2016
Externally publishedYes

Publication series

NameActa Horticulturae
Volume1134
ISSN (Print)0567-7572

Keywords

  • Bedding plants
  • Controlled environments
  • LEDs
  • Light-emitting diodes
  • Red to farred ratio
  • Young plants

ASJC Scopus subject areas

  • Horticulture

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