Abstract
Several growth parameters associated with the phytochrome-mediated shade avoidance syndrome have been measured in seedlings and mature plants of a wild-type and a hy3 mutant of Arabidopsis thaliana deficient in phytochrome B. Growth parameters were compared in plants grown in either white light (high red:far-red [R:FR] ratio) or white light plus added far-red (FR) light (low R:FR ratio). Wild-type Arabidopsis exhibited increased hypocotyl and petiole extension under a low, compared with a high, R:FR ratio. The hy3 mutant did not respond to low R:FR ratio by increase in hypocotyl or petiole length. Extension growth of wild-type plants was stimulated by brief end-of-day FR pulses, but similar treatment had no effect on extension growth of hy3 mutant plants. However, some responses to low R:FR ratio seen in the wild-type plants were also evident in the hy3 mutants. The number of days to bolting, the developmental stage at bolting, the leaf area, and the specific stem weight (weight per unit of length) all decreased in the wild-type and hy3 seedlings in response to low R:FR ratio. Low R:FR ratio caused a larger decrease in leaf area and specific stem weight in the mutant seedlings than in wild-type seedlings. The effects of low R:FR ratio on leaf area and specific stem weight were opposite to those of the hy3 lesion, which resulted in increased leaf area and specific stem weight in comparison with the wild type. Both leaf area and specific stem weight responses to low R:FR ratio also were unchanged in the ein mutant of Brassica rapa, known to be deficient in phytochrome B. These responses represent components of the shade-avoidance syndrome, and, consequently, the results indicate that phytochrome B cannot be solely responsible for the perception of R:FR ratio and the induction of shade-avoidance responses. The hypothesis is proposed that different phytochromes may be responsible for the regulation of extension growth and the regulation of lateral or radial expansion.
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Claims 11
Claim · model-written summary
Low red:far-red light increased wild-type Arabidopsis hypocotyl and petiole extension.
- Taxon
- Arabidopsis
Arabidopsise0 - Material
- Wild-type Arabidopsise0
- Treatment
- lowe0
- Outcome
- hypocotyl and petiole extensione0
- Direction
- increasede0
- Comparator
- highe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Wild-type Arabidopsis exhibited increased hypocotyl and petiole extension under a low, compared with a high, R:FR ratio.”
Claim · model-written summary
The hy3 mutant did not increase hypocotyl or petiole length at low red:far-red ratio.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Material
- hy3 mutante0
- Treatment
- low R:FR ratioe0
- Outcome
- hypocotyl or petiole lengthe0
- Direction
- did not responde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis thaliana”
e0“The hy3 mutant did not respond to low R:FR ratio by increase in hypocotyl or petiole length.”
Claim · model-written summary
End-of-day far-red pulses stimulated wild-type extension growth.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Material
- wild-type plantse0
- Treatment
- brief end-of-day FR pulsese0
- Outcome
- Extension growthe0
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis thaliana”
e0“Extension growth of wild-type plants was stimulated by brief end-of-day FR pulses”
Claim · model-written summary
End-of-day far-red pulses had no extension-growth effect in hy3 mutants.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Material
- hy3 mutant plantse0
- Treatment
- similar treatmente0
- Outcome
- extension growthe0
- Direction
- no effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis thaliana”
e0“similar treatment had no effect on extension growth of hy3 mutant plants”
Claim · model-written summary
Low red:far-red light decreased days to bolting and developmental stage at bolting in both genotypes.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Material
- wild-type and hy3 seedlingse0
- Treatment
- low R:FR ratioe0
- Outcome
- number of days to bolting, the developmental stage at boltinge0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis thaliana”
e0“The number of days to bolting, the developmental stage at bolting, the leaf area, and the specific stem weight (weight per unit of length) all decreased in the wild-type and hy3 seedlings in response to low R:FR ratio.”
Claim · model-written summary
Low red:far-red light decreased leaf area and specific stem weight in both genotypes.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Material
- wild-type and hy3 seedlingse0
- Treatment
- low R:FR ratioe0
- Outcome
- leaf area, and the specific stem weighte0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis thaliana”
e0“The number of days to bolting, the developmental stage at bolting, the leaf area, and the specific stem weight (weight per unit of length) all decreased in the wild-type and hy3 seedlings in response to low R:FR ratio.”
Claim · model-written summary
Low red:far-red light decreased leaf area and specific stem weight more in hy3 mutants than wild type.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Material
- mutant seedlingse0
- Treatment
- Low R:FR ratioe0
- Outcome
- leaf area and specific stem weighte0
- Direction
- larger decreasee0
- Comparator
- wild-type seedlingse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis thaliana”
e0“Low R:FR ratio caused a larger decrease in leaf area and specific stem weight in the mutant seedlings than in wild-type seedlings.”
Claim · model-written summary
The hy3 lesion increased leaf area and specific stem weight versus wild type.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Material
- hy3 lesione0
- Outcome
- leaf area and specific stem weighte0
- Direction
- increasede0
- Comparator
- wild typee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis thaliana”
e0“hy3 lesion, which resulted in increased leaf area and specific stem weight in comparison with the wild type”
Claim · model-written summary
Low red:far-red responses of leaf area and specific stem weight persisted in the Brassica ein mutant.
- Taxon
- Brassica rapa
Brassica rapae0 - Material
- ein mutante0
- Treatment
- low R:FR ratioe0
- Outcome
- leaf area and specific stem weight responsese0
- Direction
- unchangede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Brassica rapa”
e0“Both leaf area and specific stem weight responses to low R:FR ratio also were unchanged in the ein mutant of Brassica rapa”
Claim · model-written summary
Phytochrome B alone cannot account for red:far-red perception and shade avoidance responses.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Gene
- phytochrome Be0
- Outcome
- perception of R:FR ratio and the induction of shade-avoidance responsese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis thaliana”
e0“phytochrome B cannot be solely responsible for the perception of R:FR ratio and the induction of shade-avoidance responses”
Claim · model-written summary
Different phytochromes may regulate extension and lateral or radial expansion.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Gene
- different phytochromese0
- Outcome
- regulation of extension growth and the regulation of lateral or radial expansione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Arabidopsis thaliana”
e0“different phytochromes may be responsible for the regulation of extension growth and the regulation of lateral or radial expansion”
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See all 8 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.