Abstract
Coupled, non-cyclic electron transport was measured for chloroplasts isolated from the primary leaves of Phaseolus vulgaris. Preparations from young, fully expanded leaves gave good rates of electron transport, but the rates obtained decreased by approximately 80% during leaf senescence. Higher rates of electron transport were recorded for chloroplasts isolated from primary leaves which had regreened following removal of the remainder of the shoot. With preparations from leaves of all ages, photophosphorylation was coupled to electron transport with a mean P/2e ratio of approximately 1.3. No evidence was obtained for inactivation of chloroplasts from older leaves during isolation or assay, and it is suggested that the decrease in rate of electron transport over the period of senescence, and its increase during regreening, were consequences of changes in the composition and physical properties of the thylakoid membrane which occur in vivo. The decrease in rate of non-cyclic electron transport may be important in limiting the rate of photosynthesis in the senescing leaves.
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Claims 5
Claim · model-written summary
Electron transport rate decreased by about 80% in Phaseolus vulgaris primary leaves during senescence relative to young, fully expanded leaves.
- Taxon
- Phaseolus vulgaris
Phaseolus vulgarise0 - Treatment
- leaf senescencee1
- Outcome
- rates of electron transporte1
- Direction
- decreasede1
- Value
- approximately 80%e1
- Comparator
- young, fully expanded leavese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary leaves of Phaseolus vulgaris”
e1“Preparations from young, fully expanded leaves gave good rates of electron transport, but the rates obtained decreased by approximately 80% during leaf senescence”
Claim · model-written summary
Electron transport rates were higher in chloroplasts from regreened primary leaves after removal of the rest of the shoot.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarise0
- Organ / stage
- primary leavese2
- Treatment
- removal of the remainder of the shoote2
- Outcome
- rates of electron transporte2
- Direction
- Highere2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary leaves of Phaseolus vulgaris”
e2“Higher rates of electron transport were recorded for chloroplasts isolated from primary leaves which had regreened following removal of the remainder of the shoot”
Claim · model-written summary
Photophosphorylation was coupled to electron transport in Phaseolus vulgaris leaves of all ages, with a mean P/2e ratio of about 1.3.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarise0
- Organ / stage
- leaves of all agese3
- Outcome
- P/2e ratioe3
- Value
- approximately 1.3e3
- Qualifier
- photophosphorylation was coupled to electron transporte3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary leaves of Phaseolus vulgaris”
e3“With preparations from leaves of all ages, photophosphorylation was coupled to electron transport with a mean P/2e ratio of approximately 1.3”
Claim · model-written summary
No evidence was found for inactivation of chloroplasts from older leaves during isolation or assay.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarise0
- Organ / stage
- older leavese4
- Outcome
- inactivation of chloroplastse4
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary leaves of Phaseolus vulgaris”
e4“No evidence was obtained for inactivation of chloroplasts from older leaves during isolation or assay”
Claim · model-written summary
The decrease in non-cyclic electron transport may limit the rate of photosynthesis in senescing Phaseolus vulgaris leaves.
- Taxon
- Phaseolus vulgarisPhaseolus vulgarise0
- Organ / stage
- senescing leavese6
- Outcome
- rate of photosynthesise6
- Qualifier
- decrease in rate of non-cyclic electron transporte6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primary leaves of Phaseolus vulgaris”
e6“The decrease in rate of non-cyclic electron transport may be important in limiting the rate of photosynthesis in the senescing leaves”
The same questions in other papers
stage · physiology: photosynthesis · Phaseolus vulgaris (common bean)Positive and negative results
1 in the opposite direction
- positive
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.