Abstract
Published absorption spectra for SDS-solubilised chlorophyll-protein complexes were found to have similar mean extinction coefficients in the 400-720 nm wavelength range. Three spectral distributions of light were chosen to represent the extremes experienced by terrestrial plants: sunlight on a clear day, shadelight at ground level in a tropical rainforest and sunfleck within a wheat crop canopy. The distributions of chlorophyll between the chlorophyll-protein complexes were selected to represent the adaptation to irradiance during growth by peas and an obligate shade species Alocasia macrorrhiza. The proportion of light absorbed by each photosystem was then calculated for each light spectrum. The following conclusions were drawn: 1) Adaptation to low light by altering the relative proportions of the chlorophyll-protein complexes does not enable the chloroplast to capture shadelight more efficiently. 2) The spectrum of the ratio of light absorbed by Photosystem II (PS II) to that by Photosystem I (PS I) is qualitatively similar to spectra of the Emerson enhancement effect. 3) PS II absorbs more light than PS I and this proportion increases with adaptation to shade. Phosphorylation of the light-harvesting complex can redress the imbalance of light distribution between the two photosystems equally well in sunlight or shadelight. 4) Packaging of PS II chlorophyll in grana stacks scarcely reduces the amount of light captured by a PS II chlorophyll relative to a PS I chlorophyll. Explanations for the similarity of quantum yields for sun- and shade-adapted leaves are discussed.
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Claims 7
Claim · model-written summary
Published chlorophyll-protein spectra had similar mean extinction coefficients across 400–720 nm.
- Taxon
- peas
Lathyrus oleraceust0 - Outcome
- mean extinction coefficientse0
- Qualifier
- 400-720 nm wavelength rangee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Published absorption spectra for SDS-solubilised chlorophyll-protein complexes were found to have similar mean extinction coefficients in the 400-720 nm wavelength range.”
t0“by peas and an obligate shade species Alocasia macrorrhiza”
Claim · model-written summary
Changing complex proportions for low light did not improve shadelight capture.
- Taxon
- peasLathyrus oleraceust0
- Treatment
- altering the relative proportions of the chlorophyll-protein complexese0
- Outcome
- capture shadelight more efficientlye0
- Direction
- does not enablee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Adaptation to low light by altering the relative proportions of the chlorophyll-protein complexes does not enable the chloroplast to capture shadelight more efficiently.”
t0“by peas and an obligate shade species Alocasia macrorrhiza”
Claim · model-written summary
The PS II/PS I absorption ratio spectrum resembled the Emerson enhancement spectrum.
- Taxon
- peasLathyrus oleraceust0
- Outcome
- spectrum of the ratio of light absorbed by Photosystem II (PS II) to that by Photosystem I (PS I)e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The spectrum of the ratio of light absorbed by Photosystem II (PS II) to that by Photosystem I (PS I) is qualitatively similar to spectra of the Emerson enhancement effect.”
t0“by peas and an obligate shade species Alocasia macrorrhiza”
Claim · model-written summary
PS II absorbed more light than PS I.
- Taxon
- peasLathyrus oleraceust0
- Outcome
- lighte0
- Direction
- moree0
- Comparator
- PS Ie0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PS II absorbs more light than PS I”
t0“by peas and an obligate shade species Alocasia macrorrhiza”
Claim · model-written summary
The PS II absorption proportion increased with shade adaptation.
- Taxon
- peasLathyrus oleraceust0
- Treatment
- adaptation to shadee0
- Outcome
- this proportione0
- Direction
- increasese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“this proportion increases with adaptation to shade”
t0“by peas and an obligate shade species Alocasia macrorrhiza”
Claim · model-written summary
Light-harvesting complex phosphorylation redressed photosystem light distribution imbalance in sunlight and shade.
- Taxon
- peasLathyrus oleraceust0
- Outcome
- imbalance of light distribution between the two photosystemse0
- Qualifier
- Phosphorylation of the light-harvesting complexe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Phosphorylation of the light-harvesting complex can redress the imbalance of light distribution between the two photosystems equally well in sunlight or shadelight.”
t0“by peas and an obligate shade species Alocasia macrorrhiza”
Claim · model-written summary
PS II chlorophyll packaging in grana scarcely reduced relative PS II light capture.
- Taxon
- peasLathyrus oleraceust0
- Treatment
- Packaging of PS II chlorophyll in grana stackse0
- Outcome
- amount of light captured by a PS II chlorophylle0
- Direction
- scarcely reducese0
- Comparator
- a PS I chlorophylle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Packaging of PS II chlorophyll in grana stacks scarcely reduces the amount of light captured by a PS II chlorophyll relative to a PS I chlorophyll.”
t0“by peas and an obligate shade species Alocasia macrorrhiza”
The same questions in other papers
storage · physiology: pigments · Lathyrus oleraceus (pea)Positive and negative results
1 paper in the same direction as this paper · 1 reporting no difference from an alternative
- positive
- no effect
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.