Abstract
Simulated swards of perennial ryegrass ( Lolium perenne ) growing in 1‐m 3 soil blocks in the glasshouse were either well watered or deprived of water for 57 d and then rewatered. The first aim was to measure effects of drought on sugar (water‐soluble carbohydrate) composition of laminae and sheaths of mature laminae, and bases and laminae of young (growing) leaves. The second aim was to use pulse labelling with 14 CO 2 to follow the partitioning of recently‐fixed assimilates, and the assembly and consumption of reserve sugars (fructans). Over the last 7 d of drought growth almost stopped, old leaves died faster than they were replaced, and total sugar (which had doubled in concentration during drought) was rapidly consumed. Leaf laminae had lower content of total sugars and of large fructan (DP>5) than did growing bases and sheaths. Drought greatly reduced the rate at which sugar was exported from the laminae to the sheaths and growing leaf bases, and the rate at which it was converted to fructan. Nevertheless, fructan accumulated over the first 50 d of drought. Rewatering did not result in depolymerization and remobilization of sugars that had been formed during the last 7 d of drought, but stimulated their further assembly into high‐DP fructans. Our hypothesis, that accumulation of neo‐kestose (a DP‐3 fructan) in droughted laminae was a symptom of sugar remobilization just before death, was disproved. It is concluded that sugar reserves contribute to drought resistance only under extreme conditions. The specific role of fructan in dry environments might be to improve regrowth when drought is relieved, rather than to enhance growth during drought.
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Claims 14
Claim · model-written summary
Ryegrass growth almost stopped during the last seven days of drought.
- Taxon
- Lolium perenne
Lolium perennet0 - Treatment
- droughte0
- Outcome
- growthe0
- Direction
- almost stoppede0
- Qualifier
- last 7 de0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Over the last 7 d of drought growth almost stopped”
t0“Lolium perenne”
Claim · model-written summary
Old ryegrass leaves died faster than they were replaced late in drought.
- Taxon
- Lolium perenneLolium perennet0
- Organ / stage
- old leavese0
- Outcome
- died faster than they were replacede0
- Direction
- fastere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“old leaves died faster than they were replaced”
t0“Lolium perenne”
Claim · model-written summary
Total sugar concentration doubled during drought.
- Taxon
- Lolium perenneLolium perennet0
- Treatment
- droughte0
- Outcome
- total sugare0
- Direction
- doublede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total sugar (which had doubled in concentration during drought)”
t0“Lolium perenne”
Claim · model-written summary
Total sugar was rapidly consumed during the last seven days of drought.
- Taxon
- Lolium perenneLolium perennet0
- Outcome
- total sugare0
- Direction
- rapidly consumede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“total sugar (which had doubled in concentration during drought) was rapidly consumed”
t0“Lolium perenne”
Claim · model-written summary
Leaf laminae had less total sugar than growing bases and sheaths.
- Taxon
- Lolium perenneLolium perennet0
- Organ / stage
- Leaf laminaee0
- Outcome
- content of total sugarse0
- Direction
- lowere0
- Comparator
- growing bases and sheathse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf laminae had lower content of total sugars and of large fructan (DP>5) than did growing bases and sheaths.”
t0“Lolium perenne”
Claim · model-written summary
Leaf laminae had less large fructan than growing bases and sheaths.
- Taxon
- Lolium perenneLolium perennet0
- Organ / stage
- Leaf laminaee0
- Outcome
- large fructan (DP>5)e0
- Direction
- lowere0
- Comparator
- growing bases and sheathse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaf laminae had lower content of total sugars and of large fructan (DP>5) than did growing bases and sheaths.”
t0“Lolium perenne”
Claim · model-written summary
Drought reduced sugar export from laminae to sheaths and growing leaf bases.
- Taxon
- Lolium perenneLolium perennet0
- Treatment
- Droughte0
- Outcome
- rate at which sugar was exported from the laminae to the sheaths and growing leaf basese0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought greatly reduced the rate at which sugar was exported from the laminae to the sheaths and growing leaf bases”
t0“Lolium perenne”
Claim · model-written summary
Drought reduced conversion of sugar to fructan.
- Taxon
- Lolium perenneLolium perennet0
- Treatment
- Droughte0
- Outcome
- rate at which it was converted to fructane0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought greatly reduced the rate at which sugar was exported from the laminae to the sheaths and growing leaf bases, and the rate at which it was converted to fructan.”
t0“Lolium perenne”
Claim · model-written summary
Fructan nevertheless accumulated during the first 50 days of drought.
- Taxon
- Lolium perenneLolium perennet0
- Outcome
- fructane0
- Direction
- accumulatede0
- Qualifier
- first 50 d of droughte0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nevertheless, fructan accumulated over the first 50 d of drought.”
t0“Lolium perenne”
Claim · model-written summary
Rewatering did not depolymerize or remobilize sugars formed in the last seven drought days.
- Taxon
- Lolium perenneLolium perennet0
- Treatment
- Rewateringe0
- Outcome
- depolymerization and remobilization of sugarse0
- Direction
- did not resulte0
- Qualifier
- last 7 d of droughte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rewatering did not result in depolymerization and remobilization of sugars that had been formed during the last 7 d of drought”
t0“Lolium perenne”
Claim · model-written summary
Rewatering stimulated assembly of previously formed sugars into high-DP fructans.
- Taxon
- Lolium perenneLolium perennet0
- Treatment
- Rewateringe1
- Outcome
- further assembly into high‐DP fructanse0
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but stimulated their further assembly into high‐DP fructans”
e1“Rewatering did not result in depolymerization”
t0“Lolium perenne”
Claim · model-written summary
The hypothesis that neo-kestose accumulation marked sugar remobilization before leaf death was disproved.
- Taxon
- Lolium perenneLolium perennet0
- Outcome
- hypothesis, that accumulation of neo‐kestose (a DP‐3 fructan) in droughted laminae was a symptom of sugar remobilization just before death, was disprovede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Our hypothesis, that accumulation of neo‐kestose (a DP‐3 fructan) in droughted laminae was a symptom of sugar remobilization just before death, was disproved.”
t0“Lolium perenne”
Claim · model-written summary
Authors concluded sugar reserves contribute to drought resistance only under extreme conditions.
- Taxon
- Lolium perenneLolium perennet0
- Outcome
- drought resistancee0
- Qualifier
- sugar reserves contributee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sugar reserves contribute to drought resistance only under extreme conditions”
t0“Lolium perenne”
Claim · model-written summary
Authors proposed fructan may improve regrowth after drought relief rather than growth during drought.
- Taxon
- Lolium perenneLolium perennet0
- Outcome
- improve regrowthe0
- Qualifier
- specific role of fructan in dry environmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The specific role of fructan in dry environments might be to improve regrowth when drought is relieved, rather than to enhance growth during drought.”
t0“Lolium perenne”
The same questions in other papers
drought · growth · Lolium perenne (perennial ryegrass)Results differ
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 →rewatering · molecular: metabolites · Lolium perenne (perennial ryegrass)Results agree
1 paper in the same direction as this paper
- 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.