Abstract
Elementary processes of photoperception by phytochrome A (PhyA) for the high-irradiance response (HIR) of hypocotyl elongation in Arabidopsis were examined using a newly designed irradiator with LED. The effect of continuous irradiation with far-red (FR) light could be replaced by intermittent irradiation with FR light pulses if given at intervals of 3 min or less for 24 h. In this response, the Bunsen-Roscoe law of reciprocity held in each FR light pulse. Therefore, we determined the action spectrum for the response by intermittent irradiation using phyB and phyAphyB double mutants. The resultant action spectrum correlated well with the absorption spectrum of PhyA in far-red-absorbing phytochrome (Pfr). Intermittent irradiation with 550 to 667 nm of light alone had no significant effect on the response. In contrast, intermittent irradiation with red light immediately after each FR light pulse completely reversed the effect of FR light in each cycle. The results indicate that neither red-absorbing phytochrome synthesized in darkness nor photoconverted Pfr are physiologically active, and that a short-lived signal is induced during photoconversion from Pfr to red-absorbing phytochrome. The mode of photoperception by PhyA for HIR is essentially different from that by PhyA for very-low-fluence responses and phytochrome B for low-fluence responses.
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Claims 8
Claim · model-written summary
Far-red pulses at intervals of 3 min or less for 24 h replaced continuous irradiation in the hypocotyl response.
- Taxon
- Arabidopsis
Arabidopsise1 - Treatment
- intermittent irradiation with FR light pulsese0
- Outcome
- hypocotyl elongatione1
- Direction
- replacede0
- Value
- 3 min or less for 24 he0
- Comparator
- continuous irradiation with far-red (FR) lighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The effect of continuous irradiation with far-red (FR) light could be replaced by intermittent irradiation with FR light pulses if given at intervals of 3 min or less for 24 h.”
e1“hypocotyl elongation in Arabidopsis”
Claim · model-written summary
The Bunsen-Roscoe reciprocity law held for each far-red pulse.
- Taxon
- ArabidopsisArabidopsise1
- Outcome
- Bunsen-Roscoe law of reciprocity held in each FR light pulsee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In this response, the Bunsen-Roscoe law of reciprocity held in each FR light pulse.”
e1“hypocotyl elongation in Arabidopsis”
Claim · model-written summary
The action spectrum correlated well with PhyA absorption in Pfr.
- Taxon
- ArabidopsisArabidopsise1
- Gene
- PhyAe0
- Outcome
- action spectrume0
- Comparator
- absorption spectrum of PhyA in far-red-absorbing phytochrome (Pfr)e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The resultant action spectrum correlated well with the absorption spectrum of PhyA in far-red-absorbing phytochrome (Pfr).”
e1“hypocotyl elongation in Arabidopsis”
Claim · model-written summary
Intermittent 550 to 667 nm light alone had no significant effect on the hypocotyl response.
- Taxon
- ArabidopsisArabidopsise1
- Treatment
- Intermittent irradiation with 550 to 667 nm of light alonee0
- Outcome
- hypocotyl elongatione1
- Direction
- no significant effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Intermittent irradiation with 550 to 667 nm of light alone had no significant effect on the response.”
e1“hypocotyl elongation in Arabidopsis”
Claim · model-written summary
Red light immediately after each far-red pulse completely reversed its effect.
- Taxon
- ArabidopsisArabidopsise1
- Treatment
- intermittent irradiation with red light immediately after each FR light pulsee0
- Outcome
- hypocotyl elongatione1
- Direction
- reversede0
- Comparator
- FR lighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“intermittent irradiation with red light immediately after each FR light pulse completely reversed the effect of FR light in each cycle.”
e1“hypocotyl elongation in Arabidopsis”
Claim · model-written summary
The authors infer that dark-synthesized red-absorbing phytochrome and photoconverted Pfr are physiologically inactive.
- Taxon
- ArabidopsisArabidopsise1
- Gene
- red-absorbing phytochromee0
- Outcome
- physiologically activee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“neither red-absorbing phytochrome synthesized in darkness nor photoconverted Pfr are physiologically active”
e1“hypocotyl elongation in Arabidopsis”
Claim · model-written summary
The authors infer that conversion from Pfr to red-absorbing phytochrome induces a short-lived signal.
- Taxon
- ArabidopsisArabidopsise1
- Gene
- red-absorbing phytochromee0
- Outcome
- a short-lived signale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a short-lived signal is induced during photoconversion from Pfr to red-absorbing phytochrome”
e1“hypocotyl elongation in Arabidopsis”
Claim · model-written summary
PhyA photoperception for HIR differs essentially from PhyA very-low-fluence and phytochrome B low-fluence responses.
- Taxon
- ArabidopsisArabidopsise1
- Gene
- PhyAe0
- Outcome
- mode of photoperception by PhyA for HIRe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The mode of photoperception by PhyA for HIR is essentially different from that by PhyA for very-low-fluence responses and phytochrome B for low-fluence responses.”
e1“hypocotyl elongation in Arabidopsis”
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See all 7 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.