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High-power light-emitting diode based facility for plant cultivation
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2005 J. Phys. D: Appl. Phys. 38 3182
(http://iopscience.iop.org/0022-3727/38/17/S20)
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INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS D: APPLIED PHYSICS
J. Phys. D: Appl. Phys. 38 (2005) 3182–3187 doi:10.1088/0022-3727/38/17/020
High-power light-emitting diode based
facility for plant cultivation
G Tamulaitis1, P Duchovskis2,Z Bliznikas1, K Breiv˙e1,
R Ulinskait˙e2, A Brazaityt˙e2, A Noviˇckovas1 and A Zˇ ukauskas1
1 Institute of Materials Science and Applied Research, Vilnius University, Sauletekio al. 9-III,
LT-10222 Vilnius, Lithuania
2 Lithuanian Institute of Horticulture, Babtai, LT-54333 Kaunas District, Lithuania
E-mail: gintautas.tamulaitis@ff.vu.lt
Received 7 January 2005, in final form 30 March 2005Published 19 August 2005
Online at stacks.iop.org/JPhysD/38/3182
Abstract
Based on perspectives of the development of semiconductor materials
systems for high-power light-emitting diodes (LEDs), an illumination
facility for greenhouse plant cultivation was designed with the dominating
640 nm photosynthetically active component delivered by AlGaInP LEDs
and supplementary components fromAlGaN (photothropic action, 455 nm)
and AlGaAs (photosynthetic 660 nm and photomorphogenetic 735 nm)
LEDs. Photosynthesis intensity, photosynthetic productivity and growth
morphology as well as chlorophyll and phytohormone concentrations were
investigated in radish and lettuce grown in phytotron chambers under the
LED-based illuminators and under high-pressure sodium (HPS) lamps with
anequivalent photon flux density. Advantages of the high-power
LED-based illuminators over conventional HPS lamps, applicability of
AlGaInP LEDs for photosynthesis and control of plant growth by circadian
manipulation of a relatively weak far-red component were demonstrated.
1. Introduction
Artificial lighting for plant cultivation is an important factor,
which determines the cost and nutritionalquality of greenhouse
vegetables. Efficiency of greenhouse lighting has been
improved by application of high-pressure sodium (HPS)
lamps, which emit predominantly yellow–red light effectively
absorbed by chlorophylls. The improvement is achieved owing
to a high overall light yield and the emission spectrum suitable
for plant cultivation. However, application of light sources
with aspectrum substantially different from the solar one,
encounters difficulties owing to sensitivity of plants to the
spectral composition of light. Particularly in HPS lamps
designed for horticulture applications, the blue component
can be enhanced; however, a further purposeful tailoring of
the spectrum in the red region has physical limitations. In
principle, the spectrum can be adjusted usingphosphors, but
data on the spectrum optimal for particular plants are still
scarce and fragmental.
Light-emitting diodes (LEDs) present a versatile
alternative for artificial greenhouse lighting with numerous
advantages. In comparison with conventional HPS and
fluorescent lamps, LEDs are an energy-efficient, environmentfriendly
and longevous source of light. Assembling of LEDs,
which arealready available in the entire relevant spectral range
from near infrared (IR) to near ultraviolet (UV), enables one to
tailor the spectrum for optimal growth. Contrary to discharge
lamps, efficiency of LEDs has no physical limitations up to
100% (the values above 50% have been already demonstrated
[1]). Finally, solid-state lighting technology offers completely
new possibilities in plant...