Abstract
Levels of thylakoid components in chloroplasts and transcripts of photosynthesis-related genes were compared in leaves of different ages, namely, current, 1-year-old and 2-year-old needles, of a Japanese black pine tree (Pinus thunbergii). Levels of thylakoid components, PSI, PSII and Cyt b6/f complexes, measured as P700, Cyt b559 and Cyt f, respectively, were lowest in current needles, on a per needle basis, and were almost eight times higher in 1-year-old needles. Levels of PSI and Cyt b6/f complexes were slightly lower in 2-year-old needles while the level of PSII remained unaltered or was even slightly higher than in 1-year-old needles. The ratio of PSI to PSII decreased markedly as needles aged. By contrast, levels of cab, psaA/B, psbA, rbcS and rbcL transcripts were the highest in current needles, and the levels decreased with increasing age. The extent of the reduction was the greatest for psaA/B transcripts, with the level in 2-year-old needles being about 30% of that in current needles. The smallest reduction was observed in the level of psbA transcripts with about 90% of the current-year level in 2-year-old needles. These results suggest that PSII complex accumulates more slowly than PSI complex during leaf development, and that PSI and Cyt b6/f complexes decay before PSII during the initial period of senescence.
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Claims 9
Claim · model-written summary
PSI, PSII and Cyt b6/f were lowest in current needles and about eightfold higher at one year.
- Taxon
- Pinus thunbergii
Pinus thunbergiie1 - Organ / stage
- 1-year-old needlese0
- Outcome
- PSI, PSII and Cyt b6/f complexese0
- Direction
- highere0
- Value
- almost eight timese0
- Comparator
- current needlese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Levels of thylakoid components, PSI, PSII and Cyt b6/f complexes, measured as P700, Cyt b559 and Cyt f, respectively, were lowest in current needles, on a per needle basis, and were almost eight times higher in 1-year-old needles.”
e1“a Japanese black pine tree (Pinus thunbergii)”
Claim · model-written summary
PSI and Cyt b6/f were slightly lower in two-year-old than one-year-old needles.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Organ / stage
- 2-year-old needlese0
- Outcome
- PSI and Cyt b6/f complexese0
- Direction
- lowere0
- Comparator
- 1-year-old needlese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Levels of PSI and Cyt b6/f complexes were slightly lower in 2-year-old needles while the level of PSII remained unaltered or was even slightly higher than in 1-year-old needles.”
t0“Pine Needles”
e1“a Japanese black pine tree (Pinus thunbergii)”
Claim · model-written summary
PSII in two-year-old needles remained unchanged or slightly higher than at one year.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Outcome
- level of PSIIe0
- Direction
- unaltered or was even slightly highere0
- Comparator
- 1-year-old needlese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the level of PSII remained unaltered or was even slightly higher than in 1-year-old needles.”
t0“Pine Needles”
e1“a Japanese black pine tree (Pinus thunbergii)”
Claim · model-written summary
The PSI-to-PSII ratio decreased markedly with needle age.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Organ / stage
- needlese0
- Outcome
- ratio of PSI to PSIIe0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The ratio of PSI to PSII decreased markedly as needles aged.”
t0“Pine Needles”
e1“a Japanese black pine tree (Pinus thunbergii)”
Claim · model-written summary
Photosynthesis-gene transcripts were highest in current needles and fell with age.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Organ / stage
- current needlese0
- Gene
- cab, psaA/B, psbA, rbcS and rbcLe0
- Outcome
- transcriptse0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“levels of cab, psaA/B, psbA, rbcS and rbcL transcripts were the highest in current needles, and the levels decreased with increasing age.”
t0“Pine Needles”
e1“a Japanese black pine tree (Pinus thunbergii)”
Claim · model-written summary
psaA/B transcripts at two years were about 30% of current-needle levels.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Organ / stage
- 2-year-old needlese0
- Gene
- psaA/Be0
- Outcome
- transcriptse0
- Direction
- reductione0
- Value
- about 30%e0
- Comparator
- current needlese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The extent of the reduction was the greatest for psaA/B transcripts, with the level in 2-year-old needles being about 30% of that in current needles.”
t0“Pine Needles”
e1“a Japanese black pine tree (Pinus thunbergii)”
Claim · model-written summary
psbA transcripts at two years were about 90% of current-year levels.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Organ / stage
- 2-year-old needlese0
- Gene
- psbAe0
- Outcome
- transcriptse0
- Direction
- reductione0
- Value
- about 90%e0
- Comparator
- current-year levele0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The smallest reduction was observed in the level of psbA transcripts with about 90% of the current-year level in 2-year-old needles.”
t0“Pine Needles”
e1“a Japanese black pine tree (Pinus thunbergii)”
Claim · model-written summary
Authors infer PSII accumulates more slowly than PSI during development.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Gene
- PSIIe0
- Outcome
- PSII complex accumulatese0
- Qualifier
- during leaf developmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PSII complex accumulates more slowly than PSI complex during leaf development”
t0“Pine Needles”
e1“a Japanese black pine tree (Pinus thunbergii)”
Claim · model-written summary
Authors infer PSI and Cyt b6/f decay before PSII in early senescence.
- Taxon
- Pinus thunbergiiPinus thunbergiie1
- Outcome
- PSI and Cyt b6/f complexes decaye0
- Qualifier
- during the initial period of senescencee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“PSI and Cyt b6/f complexes decay before PSII during the initial period of senescence.”
t0“Pine Needles”
e1“a Japanese black pine tree (Pinus thunbergii)”