Post on 15-May-2020
Does “Blue” Light Invariably Cause Plant Compactness?
?
Yun Kong, Katherine Vinson, Rebecca Johnson, Devdutt Kamath, Youbin Zheng*
University of GuelphSep. 17, 2018
“Blue” vs. Red Light Effects on Elongation Inhibition
• Non-LED lightHa!ha! I win you!
My God! I will lose!
• LED light
Why? Blue light purity: LED>Non-LED
Hypothesis
Plant elongation
Red lightBlue light
PhytochromeCrosstalk
Cryptochrome
Far-red light
activate activate de-activate
inhibit
Blue light may promote elongation
• R= 100% Red • B= 100% Blue
PPFD=100 µmol m–2 s–1; Photoperiod = 24 h
• BR = 90% Blue+10% Red• BRF = BR + Far-red (R/FR=1)
R B BR BRF R B BR BRF
Petunia
Calibrachoa
Geranium
Marigold
(Kong, et al., 2018)
Questions
• What If reducing R percentage (<10%) in BR?
• What if varying R/FR ratio in BRF?
• How about other growth stages ?
Transplanting stage
• R = 100 Red• B =100 Blue• BRF0 = 94 Blue + 6 Red + 0 Far-red• BRF2 = 94 Blue + 6 Red + 2 Far-red• BRF4 = 94 Blue + 6 Red + 4 Far-red• BRF6 = 94 Blue + 6 Red + 6 Far-red
R B BRF0 BRF2 BRF4 BRF6 R B BRF0 BRF2 BRF4 BRF6
Petunia
Calibrachoa
Geranium
Marigold
PPFD = 100 µmol m–2 s–1 ; Photoperiod = 24 h
Flowering stage（1）
R B BRF0 BRF2 BRF4 BRF6
Calibrachoa
PPFD = 100 µmol m–2 s–1 ; Photoperiod = 24 h
Flowering stage（2）
R B BRF0 BRF2 BRF4 BRF6
Geranium
Marigold
PPFD = 100 µmol m–2 s–1 ; Photoperiod = 24 h
Question
• For other plant species, are there similar responses to “blue” light ?
R B BRF0 BRF2 BRF4 BRF6
Arugula
PPFD = 100 µmol m–2 s–1 ; Photoperiod = 24 h
Cabbage
R B BRF0 BRF2 BRF4 BRF6
Mustard
Kale
PPFD = 100 µmol m–2 s–1 ; Photoperiod = 24 h
R B BRF0 BRF2 BRF4 BRF6
Sunflower
Cilantro
PPFD = 100 µmol m–2 s–1 ; Photoperiod = 24 h
R B BRF0 BRF2 BRF4 BRF6
Arabidopsis
PPFD = 100 µmol m–2 s–1 ; Photoperiod = 24 h
R B BRF0 BRF2 BRF4 BRF6
Arugula
Mustard
PPFD = 100 µmol m–2 s–1 ; Photoperiod = 24 h
Question • How about higher density?
R B BRF0 BRF2 BRF4 BRF6
PPFD = 100 µmol m–2 s–1 ; Photoperiod = 24 h
Arugula
Question
100 50 100 50PPFD (µmol•m–2•s–1)
• R= 100% Red • B= 100% Blue
• BU = B + UVA (UVA/PAR =6% )• BF = B + Far-red (FR/PAR=10%)
Photoperiod = 24 h
R B BU BF R B BU BF R B BU BF R B BU BF
• What if blue light meets with low-level UVA or FR?
Arugula Cabbage
Kale Mustard
Blue light
Red light
Blue light
Red light
Arugula Mustard
20 70 120 250 450 650 20 70 120 250 450 650PPFD (µmol•m–2•s–1)
Photoperiod = 24 h
Question • What if under wider range of light intensity?
Questions
• Artifact from continuous (24h) lighting?
• How about non-continuous lighting (e.g., 16-h light/8-h dark) ?
Transplanting stage
PPFD = 100 µmol m–2 s–1
R B R B24h 16h
R B R B24h 16h
Vegetative stage
R B R B24h 16h
R B R B24h 16h
PPFD = 100 µmol m–2 s–1
Petunia
Calibrachoa
Geranium
Marigold
Flowering stage
R B R B24h 16h
PPFD = 100 µmol m–2 s–1
R B R B24h 16h
Petunia
CalibrachoaGeranium
Marigold
Other species
R B R B24h 16h
PPFD = 100 µmol m–2 s–1
R B R B24h 16h
Summary
Blue light cannot invariably cause plant compactness.
It’s inhibitory effects are related to Phytochrome activity (affected by background light ) Light intensity Plant species
What the results mean?
• Reduce plant stretching Blue light + red light Blue light + far-red light filtering coverings
• Promote plant stretching Supplemental lighting using pure blue light at night Sole lighting using pure blue light
Thanks• Michael Stasiak, Mike Dixon, Sean Ratcliffe,
Jasmine Mah., Dave Llewellyn and many more!