Abstract
Infra-red gas analysis and a quantitative radiocarbon tracer technique were used to measure photosynthesis, and the export, distribution and utilization of current assimilate in the regrowth of leaf tissue and the growth of stem and root of partially-defoliated uniculm barley plants. After defoliation, which removed all leaf tissue above the ligule of leaf 3, the rate of photosynthesis of the remaining two older leaves fell to 90–95 per cent of that of control leaves, but they exported more of their assimilated carbon to meristems elsewhere in the plant during the first 48 h after the defoliation. The level of export from the two older leaves began to decline when new leaf tissue regrew from the shoot apex, and fell below that of the control leaves 4 days after defoliation. The two older leaves supplied the assimilate used in the regrowth of new leaf tissue immediately after defoliation: previously they had exported most of their assimilate to root. There was no evidence that ‘reserves’ were mobilized to meet the needs of regrowth at leaf meristems or, indeed, of the growth in stem and root; current photosynthesis supplied sufficient assimilate to account for all observed growth. In general, the plants responded to defoliation with a rapid and marked re-allocation of assimilate from root to leaf meristems, with the result that root growth was severely retarded but new leaf tissue grew at 70–100 per cent of the rate observed in control plants.
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Claims 11
Claim · model-written summary
Defoliation lowered photosynthesis of the remaining older leaves to 90–95 percent of controls.
- Taxon
- barley plants
.jpg?width=60)
Hordeum vulgaree1 - Organ / stage
- older leavese0
- Treatment
- defoliationt0
- Outcome
- rate of photosynthesise0
- Direction
- felle0
- Value
- 90–95 per cente0
- Comparator
- control leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“the rate of photosynthesis of the remaining two older leaves fell to 90–95 per cent of that of control leaves”
t0“Defoliation”
e1“barley plants”
Claim · model-written summary
The remaining older leaves exported more assimilated carbon to meristems during the first 48 hours.
- Taxon
- barley plantsHordeum vulgaret0
- Organ / stage
- meristemse0
- Treatment
- defoliatione0
- Outcome
- exported more of their assimilated carbone0
- Direction
- moree0
- Qualifier
- first 48 he0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“they exported more of their assimilated carbon to meristems elsewhere in the plant during the first 48 h after the defoliation”
t0“barley plants”
Claim · model-written summary
Export from older leaves declined as new leaf tissue regrew.
- Taxon
- barley plantsHordeum vulgaret0
- Organ / stage
- two older leavese0
- Outcome
- level of exporte0
- Direction
- declinee0
- Qualifier
- new leaf tissue regrew from the shoot apexe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The level of export from the two older leaves began to decline when new leaf tissue regrew from the shoot apex”
t0“barley plants”
Claim · model-written summary
Older leaf export fell below controls four days after defoliation.
- Taxon
- barley plantsHordeum vulgaret0
- Treatment
- defoliatione0
- Outcome
- level of exporte1
- Direction
- fell belowe0
- Qualifier
- 4 dayse0
- Comparator
- control leavese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“fell below that of the control leaves 4 days after defoliation”
t0“barley plants”
e1“The level of export from the two older leaves”
Claim · model-written summary
The older leaves supplied assimilate for immediate regrowth of new leaf tissue.
- Taxon
- barley plantsHordeum vulgaret0
- Organ / stage
- two older leavese0
- Outcome
- assimilate used in the regrowth of new leaf tissuee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The two older leaves supplied the assimilate used in the regrowth of new leaf tissue immediately after defoliation”
t0“barley plants”
Claim · model-written summary
Before defoliation, older leaves sent most assimilate to roots.
- Taxon
- barley plantsHordeum vulgaret0
- Organ / stage
- roote0
- Outcome
- exported most of their assimilate to roote0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“previously they had exported most of their assimilate to root”
t0“barley plants”
Claim · model-written summary
No reserve mobilization was detected for leaf meristem regrowth or stem and root growth.
- Taxon
- barley plantsHordeum vulgaret0
- Organ / stage
- leaf meristemse0
- Outcome
- no evidence that ‘reserves’ were mobilizede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“There was no evidence that ‘reserves’ were mobilized to meet the needs of regrowth at leaf meristems or, indeed, of the growth in stem and root”
t0“barley plants”
Claim · model-written summary
Current photosynthesis supplied enough assimilate to account for all observed growth.
- Taxon
- barley plantsHordeum vulgaret0
- Outcome
- sufficient assimilate to account for all observed growthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“current photosynthesis supplied sufficient assimilate to account for all observed growth”
t0“barley plants”
Claim · model-written summary
Defoliation rapidly reallocated assimilate from roots to leaf meristems.
- Taxon
- barley plantsHordeum vulgaret0
- Treatment
- defoliatione0
- Outcome
- re-allocation of assimilate from root to leaf meristemse0
- Direction
- rapid and markede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the plants responded to defoliation with a rapid and marked re-allocation of assimilate from root to leaf meristems”
t0“barley plants”
Claim · model-written summary
Defoliation severely retarded root growth.
- Taxon
- barley plantsHordeum vulgaree1
- Treatment
- defoliationt0
- Outcome
- root growthe0
- Direction
- severely retardede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“root growth was severely retarded”
t0“defoliation”
e1“barley plants”
Claim · model-written summary
New leaf tissue grew at 70–100 percent of the rate in control plants.
- Taxon
- barley plantsHordeum vulgaree1
- Treatment
- defoliationt0
- Outcome
- new leaf tissue grewe0
- Value
- 70–100 per cente0
- Comparator
- control plantse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“new leaf tissue grew at 70–100 per cent of the rate observed in control plants”
t0“defoliation”
e1“barley plants”
The same questions in other papers
pruning · growth · Hordeum vulgare (barley)Positive and negative results
4 papers in the same direction as this paper · 7 in the opposite direction
- positive
- positive
- positive
8 papers more in this group
See all 12 papers →pruning · physiology: photosynthesis · Hordeum vulgare (barley)Results agree
2 papers in the same direction as this paper
- no effect
- negative
pruning · molecular: metabolites · Hordeum vulgare (barley)Results agree
2 papers in the same direction as this paper
- positive
- 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.