Abstract
1. Induction periods in carbon dioxide fixation by isolated pea chloroplasts were shortened by small quantities of Calvin-cycle intermediates. The additional fixation was larger than that which would have followed direct stoicheiometric conversion into ribulose 1,5-diphosphate. 2. When chloroplasts were illuminated in the absence of added substrates (other than carbon dioxide) soluble products were formed in the medium that stimulated fixation by fresh chloroplasts. 3. The induction periods were lengthened by washing the chloroplasts. Addition of catalytic quantities of Calvin-cycle intermediates then decreased the induction periods to their previous values. 4. The induction period was extended by a decrease in temperature but was largely unaffected by a decrease in light-intensity that was sufficient to decrease the maximum rate. 5. It is concluded that the lag periods are a consequence of the loss of Calvin-cycle intermediates, such as sugar phosphates, through the intact chloroplast envelope and that these losses can be made good by new synthesis from carbon dioxide in the reactions of the Calvin cycle.
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Claims 10
Claim · model-written summary
Small quantities of Calvin-cycle intermediates shortened carbon-fixation induction periods in pea chloroplasts.
- Taxon
- pea
Lathyrus oleraceuse0 - Treatment
- small quantities of Calvin-cycle intermediatese0
- Outcome
- Induction periods in carbon dioxide fixatione0
- Direction
- shortenede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Induction periods in carbon dioxide fixation by isolated pea chloroplasts were shortened by small quantities of Calvin-cycle intermediates.”
Claim · model-written summary
Additional fixation exceeded the amount expected from direct stoichiometric conversion to ribulose 1,5-diphosphate.
- Taxon
- peaLathyrus oleraceuse1
- Outcome
- additional fixatione0
- Direction
- largere0
- Comparator
- direct stoicheiometric conversion into ribulose 1,5-diphosphatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The additional fixation was larger than that which would have followed direct stoicheiometric conversion into ribulose 1,5-diphosphate.”
e1“isolated pea chloroplasts”
Claim · model-written summary
Illuminated chloroplasts without added substrates formed soluble products that stimulated fixation by fresh chloroplasts.
- Taxon
- peaLathyrus oleraceuse1
- Treatment
- illuminated in the absence of added substrates (other than carbon dioxide)e0
- Outcome
- soluble products were formed in the medium that stimulated fixation by fresh chloroplastse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When chloroplasts were illuminated in the absence of added substrates (other than carbon dioxide) soluble products were formed in the medium that stimulated fixation by fresh chloroplasts.”
e1“isolated pea chloroplasts”
Claim · model-written summary
Washing chloroplasts lengthened induction periods.
- Taxon
- peaLathyrus oleraceuse1
- Treatment
- washing the chloroplastse0
- Outcome
- induction periodse0
- Direction
- lengthenede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The induction periods were lengthened by washing the chloroplasts.”
e1“isolated pea chloroplasts”
Claim · model-written summary
Catalytic quantities of Calvin-cycle intermediates restored induction periods to previous values after washing.
- Taxon
- peaLathyrus oleraceuse1
- Treatment
- Addition of catalytic quantities of Calvin-cycle intermediatese0
- Outcome
- induction periodse0
- Direction
- decreasede0
- Comparator
- their previous valuese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Addition of catalytic quantities of Calvin-cycle intermediates then decreased the induction periods to their previous values.”
e1“isolated pea chloroplasts”
Claim · model-written summary
Lower temperature extended the induction period.
- Taxon
- peaLathyrus oleraceuse1
- Treatment
- a decrease in temperaturee0
- Outcome
- induction periode0
- Direction
- extendede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The induction period was extended by a decrease in temperature”
e1“isolated pea chloroplasts”
Claim · model-written summary
Lower light intensity largely did not affect the induction period.
- Taxon
- peaLathyrus oleraceuse2
- Treatment
- a decrease in light-intensitye0
- Outcome
- induction periode1
- Direction
- largely unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“was largely unaffected by a decrease in light-intensity that was sufficient to decrease the maximum rate”
e1“The induction period was extended”
e2“isolated pea chloroplasts”
Claim · model-written summary
Lower light intensity decreased the maximum rate.
- Taxon
- peaLathyrus oleraceuse1
- Treatment
- a decrease in light-intensitye0
- Outcome
- maximum ratee0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“a decrease in light-intensity that was sufficient to decrease the maximum rate”
e1“isolated pea chloroplasts”
Claim · model-written summary
The authors attribute induction lags to loss of Calvin-cycle intermediates through the intact chloroplast envelope.
- Taxon
- peaLathyrus oleraceuse1
- Outcome
- lag periodse0
- Qualifier
- loss of Calvin-cycle intermediates, such as sugar phosphates, through the intact chloroplast envelopee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the lag periods are a consequence of the loss of Calvin-cycle intermediates, such as sugar phosphates, through the intact chloroplast envelope”
e1“isolated pea chloroplasts”
Claim · model-written summary
The authors conclude that new synthesis from carbon dioxide in Calvin-cycle reactions replaces lost intermediates.
- Taxon
- peaLathyrus oleraceuse1
- Outcome
- these losses can be made goode0
- Qualifier
- new synthesis from carbon dioxide in the reactions of the Calvin cyclee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“these losses can be made good by new synthesis from carbon dioxide in the reactions of the Calvin cycle”
e1“isolated pea chloroplasts”