Abstract
Rapid effects of light on wheat seedling extension growth were monitored by sensitive transducer techniques. Seedlings grown in complete darkness responded to light by a marked deceleration of extension growth after a mean latent period of 10.4 minutes. Pulses (5 minutes) of red (660 nanometers), green (530 nanometers), and far-red (730 nanometers) light caused marked extension rate depression, and the red effect could not be reversed by 730 nanometers far-red. Pulses of 1 second red (72 micromoles per square meter) were effective, and were reversible by immediate long wavelength (759 nanometers) far-red. Seedlings pretreated with 2 minute broadband green light (0.6 micromole per square meter), 28 hours prior to the experimental light treatments, displayed similar extension rate decelerations in response to red light, but after a longer mean lag of 23.75 minutes. No response was observed with red light treatments of less than 1 minute, and the effects of 5 minutes of red light were fully reversible by 5 minutes of 730 nanometers far-red. Fluence-response curves showed that nonpretreated seedlings were approximately 100 times more sensitive to far-red-absorbing form of phytochrome than were those given prior light treatment. Although the fluence-response relationship for nonpretreated seedlings matched the photoconversion kinetics of phytochrome reasonably well, that for the pretreated seedlings indicated a requirement for repeated photoconversions for maximum action. The results are discussed in relation to the possibility that phytochrome may regulate the availability, or the activity, of a component of its own transduction chain.
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Claims 8
Claim · model-written summary
Dark-grown wheat seedlings decelerated extension growth after light exposure, with a mean latency of 10.4 minutes.
- Taxon
- Wheat
Triticum aestivumt0 - Treatment
- lighte0
- Outcome
- extension growthe0
- Direction
- deceleratione0
- Value
- 10.4 minutese0
- Comparator
- complete darknesse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seedlings grown in complete darkness responded to light by a marked deceleration of extension growth after a mean latent period of 10.4 minutes.”
t0“Wheat”
Claim · model-written summary
Five-minute red, green and far-red pulses depressed extension rate.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- Pulses (5 minutes) of red (660 nanometers), green (530 nanometers), and far-red (730 nanometers) lighte0
- Outcome
- extension ratee0
- Direction
- depressione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pulses (5 minutes) of red (660 nanometers), green (530 nanometers), and far-red (730 nanometers) light caused marked extension rate depression”
t0“Wheat”
Claim · model-written summary
The five-minute red-light effect was not reversed by 730-nanometer far-red light.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- red effect could not be reversed by 730 nanometers far-rede0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the red effect could not be reversed by 730 nanometers far-red”
t0“Wheat”
Claim · model-written summary
One-second red pulses were effective and immediately reversible by 759-nanometer far-red light.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- were effective, and were reversible by immediate long wavelength (759 nanometers) far-rede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pulses of 1 second red (72 micromoles per square meter) were effective, and were reversible by immediate long wavelength (759 nanometers) far-red.”
t0“Wheat”
Claim · model-written summary
Green-pretreated seedlings showed red-light-induced deceleration after a longer mean lag of 23.75 minutes.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- red lighte0
- Outcome
- extension ratee0
- Direction
- decelerationse0
- Value
- 23.75 minutese0
- Qualifier
- pretreated with 2 minute broadband green light (0.6 micromole per square meter), 28 hours priore0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Seedlings pretreated with 2 minute broadband green light (0.6 micromole per square meter), 28 hours prior to the experimental light treatments, displayed similar extension rate decelerations in response to red light, but after a longer mean lag of 23.75 minutes.”
t0“Wheat”
Claim · model-written summary
Green-pretreated seedlings showed no response to red light for less than one minute.
- Taxon
- WheatTriticum aestivumt0
- Treatment
- red light treatments of less than 1 minutee0
- Outcome
- responsee0
- Direction
- No responsee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No response was observed with red light treatments of less than 1 minute”
t0“Wheat”
Claim · model-written summary
In green-pretreated seedlings, five minutes of red light was fully reversible by five minutes of 730-nanometer far-red.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- effects of 5 minutes of red light were fully reversible by 5 minutes of 730 nanometers far-rede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the effects of 5 minutes of red light were fully reversible by 5 minutes of 730 nanometers far-red”
t0“Wheat”
Claim · model-written summary
Nonpretreated seedlings were approximately 100 times more sensitive to the far-red-absorbing form of phytochrome than pretreated seedlings.
- Taxon
- WheatTriticum aestivumt0
- Outcome
- sensitive to far-red-absorbing form of phytochromee0
- Direction
- more sensitivee0
- Value
- approximately 100 timese0
- Comparator
- those given prior light treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nonpretreated seedlings were approximately 100 times more sensitive to far-red-absorbing form of phytochrome than were those given prior light treatment”
t0“Wheat”
The same questions in other papers
light · growth · Triticum aestivum (wheat)Positive and negative results
38 papers in the same direction as this paper · 46 in the opposite direction
- no effect
- no effect
- positive
81 papers more in this group
See all 85 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.