Abstract
Seeds of the C4 dicot Flaveria bidentis and the C3 dicot Nicotiana tabacum were germinated on expanded cotton plugs and grown for 28–35 days in a sterile culture system with liquid nutrients supplied to the roots in the presence or absence of 5% (w/v) sucrose. Despite previous reports that supplying sucrose exogenously to plants inhibits expression of photosynthetic genes, sucrose application in this system stimulated maximum photosynthetic rates and these were comparable to those measured in glasshouse-grown material. The activities of many photosynthetic enzymes in the youngest fully expanded leaves of both Flaveria and tobacco plants were increased by sucrose feeding. Sucrose levels were increased more than 2-fold in tobacco and 3-fold in Flaveria leaves (on a leaf area basis) by sucrose application, and both hexose and starch levels also increased. Chlorophyll per unit leaf area in sucrose-fed plants increased by approximately 20% in tobacco and 2-fold in Flaveria . There was no evidence of sucrose repression of photosynthetic competence in this experimental system. We propose that, over the concentration range present in the leaves in these experiments, sucrose acts as a positive signal for photosynthetic gene expression but that, above a threshold level, inhibition of gene expression seen in other studies could still occur.
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Claims 9
Claim · model-written summary
Sucrose feeding stimulated maximum photosynthetic rates in tobacco and Flaveria.
- Taxon
- tobacco
Nicotiana tabacumt0 - Treatment
- sucrose applicatione0
- Outcome
- maximum photosynthetic ratese0
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sucrose application in this system stimulated maximum photosynthetic rates”
t0“Effects of Exogenous Sucrose Feeding on Photosynthesis in the C 3 Plant Tobacco and the C 4 Plant Flaveria bidentis”
Claim · model-written summary
Photosynthetic enzyme activities increased with sucrose feeding in young leaves of both species.
- Taxon
- Flaveria and tobaccoNicotiana tabacum
Flaveriae0 - Organ / stage
- youngest fully expanded leavese0
- Treatment
- sucrose feedinge0
- Outcome
- activities of many photosynthetic enzymese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The activities of many photosynthetic enzymes in the youngest fully expanded leaves of both Flaveria and tobacco plants were increased by sucrose feeding”
t0“Effects of Exogenous Sucrose Feeding on Photosynthesis in the C 3 Plant Tobacco and the C 4 Plant Flaveria bidentis”
Claim · model-written summary
Sucrose levels in tobacco leaves rose more than twofold after sucrose application.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- sucrose applicatione0
- Outcome
- Sucrose levelse0
- Direction
- increasede0
- Value
- more than 2-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sucrose levels were increased more than 2-fold in tobacco and 3-fold in Flaveria leaves (on a leaf area basis) by sucrose application”
t0“Effects of Exogenous Sucrose Feeding on Photosynthesis in the C 3 Plant Tobacco and the C 4 Plant Flaveria bidentis”
Claim · model-written summary
Sucrose levels in Flaveria leaves rose threefold after sucrose application.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Sucrose levels were increased more than 2-fold in tobacco and 3-fold in Flaveria leaves (on a leaf area basis) by sucrose application”
t0“Effects of Exogenous Sucrose Feeding on Photosynthesis in the C 3 Plant Tobacco and the C 4 Plant Flaveria bidentis”
Claim · model-written summary
Hexose and starch levels also increased with sucrose feeding.
- Taxon
- tobaccoNicotiana tabacumt0
- Treatment
- sucrose feedingt0
- Outcome
- hexose and starch levelse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both hexose and starch levels also increased”
t0“Effects of Exogenous Sucrose Feeding on Photosynthesis in the C 3 Plant Tobacco and the C 4 Plant Flaveria bidentis”
Claim · model-written summary
Sucrose feeding increased tobacco chlorophyll per leaf area by approximately 20%.
- Taxon
- tobaccoNicotiana tabacume0
- Treatment
- sucrose-fede0
- Outcome
- Chlorophyll per unit leaf areae0
- Direction
- increasede0
- Value
- approximately 20%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorophyll per unit leaf area in sucrose-fed plants increased by approximately 20% in tobacco”
t0“Effects of Exogenous Sucrose Feeding on Photosynthesis in the C 3 Plant Tobacco and the C 4 Plant Flaveria bidentis”
Claim · model-written summary
Sucrose feeding doubled chlorophyll per leaf area in Flaveria.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Chlorophyll per unit leaf area in sucrose-fed plants increased by approximately 20% in tobacco and 2-fold in Flaveria”
t0“Effects of Exogenous Sucrose Feeding on Photosynthesis in the C 3 Plant Tobacco and the C 4 Plant Flaveria bidentis”
Claim · model-written summary
The authors found no evidence of sucrose repression of photosynthetic competence in this system.
- Taxon
- tobaccoNicotiana tabacumt0
- Outcome
- sucrose repression of photosynthetic competencee0
- Direction
- no evidencee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was no evidence of sucrose repression of photosynthetic competence in this experimental system”
t0“Effects of Exogenous Sucrose Feeding on Photosynthesis in the C 3 Plant Tobacco and the C 4 Plant Flaveria bidentis”
Claim · model-written summary
The authors propose sucrose positively signals photosynthetic gene expression within the studied leaf concentration range.
- Taxon
- tobaccoNicotiana tabacumt0
- Compound
- sucrosee0
- Outcome
- photosynthetic gene expressione0
- Qualifier
- positive signale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sucrose acts as a positive signal for photosynthetic gene expression”
t0“Effects of Exogenous Sucrose Feeding on Photosynthesis in the C 3 Plant Tobacco and the C 4 Plant Flaveria bidentis”
The same questions in other papers
sucrose · physiology: photosynthesis · Nicotiana tabacum (tobacco)Positive and negative results
2 papers in the same direction as this paper · 3 in the opposite direction
- positive
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See all 6 papers →sucrose · quality: sugar starch · Nicotiana tabacum (tobacco)Results agree
1 paper in the same direction as this paper
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infection · quality: sugar starch · Nicotiana tabacum (tobacco)Positive and negative results
1 in the opposite direction
- negative
infection · physiology: photosynthesis · Nicotiana tabacum (tobacco)Positive and negative results
4 in the opposite direction
- negative
- negative
- negative
1 paper more in this group
See all 5 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.