Abstract
This investigation was initiated to study the effect of CO₂ on phytochrome-mediated morphogenesis in flowering and seed germination. Removal of CO₂ by flushing the plant environment with CO₂-free air inhibited the red light interruption effects on flowering in Xanthium pennsylvanicum and on seed germination in Lactuca sativa cv Grand Rapids. Further experiments were done to investigate the involvement of CO₂ exchange in the effects of night interruptions on flowering in Xanthium. ¹⁴CO₂ feeding trials showed that red light given for 5 minutes caused a net increase in ¹⁴C activity in the ethanol soluble fraction when ¹⁴CO₂ was fed during the light treatment. There was no effect of red light on the extent of ¹⁴CO₂ fixation in the dark period immediately following red light. The types of free amino acids recovered after paper chromatography were essentially the same after ¹⁴CO₂ feedings in darkness, red light, and far red light following red light. However, there was a considerable increase in ¹⁴C activity in most of the amino acids in leaves given red light interruption, and the amount further increased when far red light was given following the red light. The extent of ¹⁴C label in tyrosine, valine and leucine was essentially the same in all the three treatments. In CO₂-exchange experiments using the IRGA, brief red or far red light treatments were applied to Xanthium plants under inductive dark periods and the subsequent flowering response was assessed according to bud morphology. The occurrence of flowering depended on the timing, wavelength and intensity of the light treatments, and on the CCL concentration during the light treatments. CO₂ exchange was measured during the night interruptions in single attached leaves. CO₂ exchange was influenced by the conditions during the night interruptions, but there was no apparent correlation between the pattern of CO₂ exchange observed and the subsequent flowering response. It appears that the action of during night interruptions is not associated with the exchange of during the night interruption. In an attempt to investigate other possible roles of CO₂, experiments were done with light sensitive lettuce and Amaranthus retroflexus L. seeds. These experiments pertained to changes in pH of the incubation medium and CO₂ concentration simultaneously. Germination was strongly promoted at pH 4.0 but the promotion diminished with increases in pH and did not occur at pH 7.5. The response of germination to red irradiation was suppressed by CO₂ removal and enhanced by CO₂ enrichment in air or atmospheres. There was a close similarity between the pH effects on percentage germination and pH dependence of the CO₂ /HCO₃ - equilibrium. Transfer experiments, in which lettuce seeds were exchanged between buffers of pH 4.0 and pH 3.0, showed that the red/far red photo-transformation of phytochrome v/as independent of pH. Low pH, however, was required for onset of germination following red irradiation. Thereafter, pH between 4.0 and 8.0 did not limit the progress of germination. It is postulated that following red irradiation, a product develops which is distinguishable from the Pfr form of phytochrome. The product is stable at pH 8.0 and at pH 4.0 it acts to promote germination.
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Claims 18
Claim · model-written summary
CO₂ removal inhibited the red-light interruption effect on Xanthium flowering.
- Taxon
- Xanthium pennsylvanicume0
- Treatment
- CO₂-free aire0
- Outcome
- red light interruption effects on floweringe0
- Direction
- inhibitede0
Not reportedComparator
Verbatim
e0“Removal of CO₂ by flushing the plant environment with CO₂-free air inhibited the red light interruption effects on flowering in Xanthium pennsylvanicum”
Claim · model-written summary
CO₂ removal inhibited the red-light interruption effect on Lactuca seed germination.
- Taxon
- Lactuca sativa
Lactuca sativae0 - Material
- Grand Rapidse0
- Treatment
- CO₂-free aire1
- Outcome
- seed germinatione0
- Direction
- inhibitede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“on seed germination in Lactuca sativa cv Grand Rapids”
e1“Removal of CO₂ by flushing the plant environment with CO₂-free air inhibited the red light interruption effects”
Claim · model-written summary
Five minutes of red light increased ¹⁴C activity in the ethanol-soluble fraction when ¹⁴CO₂ was fed during light treatment.
- Treatment
- red light given for 5 minutese0
- Outcome
- ¹⁴C activity in the ethanol soluble fractione0
- Direction
- increasee0
XanthiumNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“red light given for 5 minutes caused a net increase in ¹⁴C activity in the ethanol soluble fraction when ¹⁴CO₂ was fed during the light treatment”
e1“flowering in Xanthium. ¹⁴CO₂ feeding trials”
Claim · model-written summary
Red light had no effect on ¹⁴CO₂ fixation in the following dark period.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was no effect of red light on the extent of ¹⁴CO₂ fixation in the dark period immediately following red light.”
e1“flowering in Xanthium. ¹⁴CO₂ feeding trials”
Claim · model-written summary
Recovered free amino acid types were essentially the same across darkness, red light and far red light following red light.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The types of free amino acids recovered after paper chromatography were essentially the same after ¹⁴CO₂ feedings in darkness, red light, and far red light following red light.”
e1“flowering in Xanthium. ¹⁴CO₂ feeding trials”
Claim · model-written summary
Red-light interruption increased ¹⁴C activity in most leaf amino acids.
- Treatment
- red light interruptione0
- Outcome
- ¹⁴C activity in most of the amino acids in leavese0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“there was a considerable increase in ¹⁴C activity in most of the amino acids in leaves given red light interruption”
e1“flowering in Xanthium. ¹⁴CO₂ feeding trials”
Claim · model-written summary
Far-red light after red light further increased leaf amino acid ¹⁴C activity.
- Treatment
- far red lighte0
- Outcome
- ¹⁴C activity in most of the amino acids in leavese1
- Direction
- further increasede0
- Comparator
- red lighte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the amount further increased when far red light was given following the red light”
e1“¹⁴C activity in most of the amino acids in leaves”
e2“flowering in Xanthium. ¹⁴CO₂ feeding trials”
Claim · model-written summary
Tyrosine, valine and leucine labeling was essentially the same across the three light treatments.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The extent of ¹⁴C label in tyrosine, valine and leucine was essentially the same in all the three treatments.”
e1“flowering in Xanthium. ¹⁴CO₂ feeding trials”
Claim · model-written summary
Xanthium flowering depended on light timing, wavelength and intensity and CO₂ concentration.
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The occurrence of flowering depended on the timing, wavelength and intensity of the light treatments, and on the CCL concentration during the light treatments.”
e1“Xanthium plants”
Claim · model-written summary
Night-interruption conditions influenced CO₂ exchange without apparent correlation to later flowering.
- Treatment
- conditions during the night interruptionse0
- Outcome
- subsequent flowering responsee0
- Direction
- no apparent correlatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CO₂ exchange was influenced by the conditions during the night interruptions, but there was no apparent correlation between the pattern of CO₂ exchange observed and the subsequent flowering response.”
e1“Xanthium plants”
Claim · model-written summary
Germination was strongly promoted at pH 4.0, with promotion diminishing as pH rose and absent at pH 7.5.
- Taxon
- Amaranthus retroflexus L.
Amaranthus retroflexuse1 - Treatment
- pH 4.0e0
- Outcome
- Germinatione0
- Direction
- strongly promotede0
- Comparator
- pH 7.5e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Germination was strongly promoted at pH 4.0 but the promotion diminished with increases in pH and did not occur at pH 7.5.”
e1“lettuce and Amaranthus retroflexus L. seeds”
Claim · model-written summary
CO₂ removal suppressed the germination response to red irradiation.
- Taxon
- Amaranthus retroflexus L.Amaranthus retroflexuse1
- Treatment
- CO₂ removale0
- Outcome
- response of germination to red irradiatione0
- Direction
- suppressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The response of germination to red irradiation was suppressed by CO₂ removal”
e1“Amaranthus retroflexus L. seeds”
Claim · model-written summary
CO₂ enrichment enhanced the germination response to red irradiation.
- Taxon
- Amaranthus retroflexus L.Amaranthus retroflexuse2
- Treatment
- CO₂ enrichmente0
- Outcome
- response of germination to red irradiatione1
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“enhanced by CO₂ enrichment in air or atmospheres”
e1“The response of germination to red irradiation”
e2“Amaranthus retroflexus L. seeds”
Claim · model-written summary
pH effects on germination percentage closely resembled the pH dependence of CO₂/HCO₃ equilibrium.
- Taxon
- lettuceLactuca sativae1
- Treatment
- pHe0
- Outcome
- percentage germinatione0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was a close similarity between the pH effects on percentage germination and pH dependence of the CO₂ /HCO₃ - equilibrium.”
e1“lettuce seeds”
Claim · model-written summary
Red/far-red phytochrome transformation in lettuce seeds was independent of pH.
- Taxon
- lettuceLactuca sativae1
- Treatment
- pHe0
- Outcome
- red/far red photo-transformation of phytochromee0
- Direction
- independent of pHe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the red/far red photo-transformation of phytochrome v/as independent of pH.”
e1“lettuce seeds”
Claim · model-written summary
Low pH was required to initiate germination after red irradiation.
- Taxon
- lettuceLactuca sativae1
- Outcome
- onset of germinatione0
- Qualifier
- Low pHe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Low pH, however, was required for onset of germination following red irradiation.”
e1“lettuce seeds”
Claim · model-written summary
After onset, pH 4.0 to 8.0 did not limit germination progress.
- Taxon
- lettuceLactuca sativae1
- Treatment
- pH between 4.0 and 8.0e0
- Outcome
- progress of germinatione0
- Direction
- did not limite0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Thereafter, pH between 4.0 and 8.0 did not limit the progress of germination.”
e1“lettuce seeds”
Claim · model-written summary
Authors postulate a red-light-derived product distinct from Pfr that is stable at pH 8.0 and promotes germination at pH 4.0.
- Taxon
- lettuceLactuca sativae1
- Outcome
- promote germinatione0
- Qualifier
- a product develops which is distinguishable from the Pfr form of phytochromee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It is postulated that following red irradiation, a product develops which is distinguishable from the Pfr form of phytochrome. The product is stable at pH 8.0 and at pH 4.0 it acts to promote germination.”
e1“lettuce seeds”
The same questions in other papers
co2 · growth · Amaranthus retroflexus (redroot amaranth)Positive and negative results
1 paper in the same direction as this paper · 5 in the opposite direction
- no effect
- no effect
- no effect
3 papers more in this group
See all 7 papers →ph · growth · Lactuca sativa (garden lettuce)Positive and negative results
10 papers in the same direction as this paper · 11 in the opposite direction
- positive
- positive
- positive
18 papers more in this group
See all 22 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.