Paper · 2010 · Functional Plant Biology

Grazing winter wheat relieves plant water stress and transiently enhances photosynthesis

Matthew T. Harrison; Walter M. Kelman; Andrew D. Moore; et al.

12
claims
24
verbatim quotes
61
citations
2
research areas
✓
Open access

Abstract

To model the impact of grazing on the growth of wheat (Triticum aestivum L.), we measured photosynthesis in the field. Grazing may affect photosynthesis as a consequence of changes to leaf water status, nitrogen content per unit leaf area (Na) or photosynthetic enzyme activity. While light-saturated CO2 assimilation rates (Asat) of field-grown wheat were unchanged during grazing, Asat transiently increased by 33–68% compared with ungrazed leaves over a 2- to 4-week period after grazing ended. Grazing reduced leaf mass per unit area, increased stomatal conductance and increased intercellular CO2 concentrations (Ci) by 36–38%, 88–169% and 17–20%, respectively. Grazing did not alter Na. Using a photosynthesis model, we demonstrated that the increase in Asat after grazing required an increase in Rubisco activity of up to 53%, whereas the increase in Ci could only increase Asat by up to 13%. Increased Rubisco activity was associated with a partial alleviation of leaf water stress. We observed a 68% increase in leaf water potential of grazed plants that could be attributed to reduced leaf area index and canopy evaporative demand, as well as to increased rainfall infiltration into soil. The grazing of rain-fed grain cereals may be tailored to relieve plant water stress and enhance leaf photosynthesis.

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The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.

Claims 12

Intervention effectobservedoriginal resultno effectmeasured

Claim · model-written summary

Photosynthetic CO2 assimilation was unchanged during grazing.

Treatment
grazinge1
Outcome
light-saturated CO2 assimilation rates (Asat)e1
Direction
unchangede1

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“light-saturated CO2 assimilation rates (Asat) of field-grown wheat were unchanged during grazing”

✓ located verbatim in the source · abstract, characters 285–381 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Assimilation rose by 33–68% for 2 to 4 weeks after grazing ended versus ungrazed leaves.

Treatment
grazinge1
Outcome
Asate1
Direction
increasede1
Value
33–68%e1
Qualifier
2- to 4-week periode1
Comparator
ungrazed leavese1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“Asat transiently increased by 33–68% compared with ungrazed leaves over a 2- to 4-week period after grazing ended”

✓ located verbatim in the source · abstract, characters 383–496 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Grazing reduced leaf mass per unit area by 36–38%.

Treatment
Grazinge1
Outcome
leaf mass per unit areae1
Direction
reducede1
Value
36–38%e1

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“Grazing reduced leaf mass per unit area, increased stomatal conductance and increased intercellular CO2 concentrations (Ci) by 36–38%, 88–169% and 17–20%, respectively”

✓ located verbatim in the source · abstract, characters 498–665 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Grazing increased stomatal conductance by 88–169%.

Treatment
Grazinge1
Outcome
stomatal conductancee1
Direction
increasede1
Value
88–169%e1

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“Grazing reduced leaf mass per unit area, increased stomatal conductance and increased intercellular CO2 concentrations (Ci) by 36–38%, 88–169% and 17–20%, respectively”

✓ located verbatim in the source · abstract, characters 498–665 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Grazing increased intercellular CO2 concentrations (Ci) by 17–20%.

Treatment
Grazinge1
Outcome
intercellular CO2 concentrations (Ci)e1
Direction
increasede1
Value
17–20%e1

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“Grazing reduced leaf mass per unit area, increased stomatal conductance and increased intercellular CO2 concentrations (Ci) by 36–38%, 88–169% and 17–20%, respectively”

✓ located verbatim in the source · abstract, characters 498–665 · show in text ↑
Intervention effectobservedoriginal resultno effectmeasured

Claim · model-written summary

Grazing did not alter leaf nitrogen content per unit area.

Treatment
Grazinge1
Outcome
Nae1
Direction
did not altere1

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“Grazing did not alter Na”

✓ located verbatim in the source · abstract, characters 667–691 · show in text ↑
Mechanismobservedoriginal resultpositivesimulated

Claim · model-written summary

The photosynthesis model required up to 53% greater Rubisco activity to explain increased assimilation after grazing.

Gene
Rubiscoe1
Outcome
increase in Asate1
Direction
increasee1
Value
53%e1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“the increase in Asat after grazing required an increase in Rubisco activity of up to 53%”

✓ located verbatim in the source · abstract, characters 744–832 · show in text ↑
Mechanismobservedoriginal resultpositivesimulated

Claim · model-written summary

The modeled intercellular CO2 increase could raise assimilation by at most 13%.

Outcome
Asate1
Direction
increasee1
Value
13%e1
Qualifier
increase in Cie1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“the increase in Ci could only increase Asat by up to 13%”

✓ located verbatim in the source · abstract, characters 842–898 · show in text ↑
Associationobservedoriginal resultpositivemeasured

Claim · model-written summary

Greater Rubisco activity was associated with partial relief of leaf water stress.

Gene
Rubiscoe1
Outcome
leaf water stresse1
Direction
alleviatione1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“Increased Rubisco activity was associated with a partial alleviation of leaf water stress”

✓ located verbatim in the source · abstract, characters 900–989 · show in text ↑
Intervention effectobservedoriginal resultpositivemeasured

Claim · model-written summary

Grazed plants had 68% higher leaf water potential.

Treatment
grazede1
Outcome
leaf water potentiale1
Direction
increasee1
Value
68%e1

Not reportedComparator

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“68% increase in leaf water potential of grazed plants”

✓ located verbatim in the source · abstract, characters 1005–1058 · show in text ↑
Mechanismobservedoriginal resultpositivemeasured

Claim · model-written summary

Reduced canopy evaporative demand and leaf area index, and increased soil rainfall infiltration were attributed as causes of higher leaf water potential.

Outcome
leaf area index and canopy evaporative demande1
Qualifier
increased rainfall infiltration into soile1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“attributed to reduced leaf area index and canopy evaporative demand, as well as to increased rainfall infiltration into soil”

✓ located verbatim in the source · abstract, characters 1073–1197 · show in text ↑
Recommendationobservedoriginal resultpositivebasis n/a

Claim · model-written summary

Grazing rain-fed grain cereals may be adjusted to relieve water stress and enhance leaf photosynthesis.

Treatment
grazinge1
Outcome
relieve plant water stress and enhance leaf photosynthesise1

Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Triticum aestivum
Triticum aestivum · TaxonRasbak · CC BY-SA 3.0 · Wikimedia Commons ↗

Verbatim

e0

“wheat (Triticum aestivum L.)”

✓ located verbatim in the source · abstract, characters 48–76 · show in text ↑
e1

“The grazing of rain-fed grain cereals may be tailored to relieve plant water stress and enhance leaf photosynthesis”

✓ located verbatim in the source · abstract, characters 1199–1314 · show in text ↑

grazing · growth · Triticum aestivum (wheat)Results differ

20 papers: 6 positive, 14 negative or no effect

5 papers in the same direction as this paper · 13 in the opposite direction · 1 reporting no difference from an alternative

  1. negative
  2. negative
  3. negative

16 papers more in this group

See all 20 papers →

grazing · physiology: gas exchange · Triticum aestivum (wheat)Positive and negative results

2 papers: 1 positive, 1 negative or no effect

1 in the opposite direction

  1. negative
See all 2 papers →

grazing · physiology: water · Triticum aestivum (wheat)Positive and negative results

2 papers: 1 positive, 1 negative or no effect

1 in the opposite direction

  1. negative
See all 2 papers →

grazing · physiology: photosynthesis · Triticum aestivum (wheat)Positive and negative results

2 papers: 1 positive, 1 negative or no effect

1 in the opposite direction

  1. positive
See all 2 papers →

grazing · nutrient: content · Triticum aestivum (wheat)Positive and negative results

4 papers: 2 positive, 2 negative or no effect

1 paper in the same direction as this paper · 2 in the opposite direction

  1. positive
  2. positive
  3. negative
See all 4 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.