Abstract
Lowland rice ( Oryza sativa L.) responds positively to increased atmospheric CO 2 concentration. However, the efficiency of the canopy depends on the N status of the plant, which could vary with the change in uptake and partitioning of N with increased atmospheric CO 2 . A field experiment was conducted at the International Rice Research Institute (IRRI) to determine changes in N requirement of the rice crop and to propose suitable management strategies to overcome tissue N dilution with increased CO 2 concentration. Rice variety IR72 was grown inside open top chambers at ambient (about 350 μmol mol −1 ) or elevated (700 μmol mol −1 ) atmospheric CO 2 in combination with three levels of applied N (0, 90, or 200 kg N ha −1 ). Rooting of rice was linearly related to tillering, and the relationship did not change with CO 2 concentrations, but with age of the crop. When adequate N was not supplied, rice plants grown at high CO 2 became inferior to plants grown at ambient CO 2 . N uptake and fertilizer N recovery was higher in plants grown in high CO 2 until maximum tillering, but the partitioning of N towards leaves decreased by 9%. Acclimation to high CO 2 by rice may, therefore, be dependent on the N uptake. Increased N uptake under high CO 2 environment was related to its larger root system , which was due to increased unproductive tillering. This suggests that if tillering is limited, rice plants at high CO 2 may suffer from N limitation due to changes in both uptake and partitioning. It is concluded that management of the rice crop grown at high atmospheric CO 2 should be different to that under current conditions.
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Claims 10
Claim · model-written summary
Rice rooting was linearly related to tillering.
- Taxon
- rice
Oryza sativae0 - Organ / stage
- tilleringe0
- Outcome
- Rootinge0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rooting of rice was linearly related to tillering”
Claim · model-written summary
The rooting and tillering relationship did not change with CO2 concentration.
- Taxon
- riceOryza sativae1
- Treatment
- CO 2 concentrationse0
- Outcome
- relationshipe0
- Direction
- did not changee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the relationship did not change with CO 2 concentrations”
e1“Rooting of rice was linearly related to tillering”
Claim · model-written summary
The rooting and tillering relationship changed with crop age.
- Taxon
- riceOryza sativae1
- Organ / stage
- age of the crope0
- Outcome
- relationshipe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the relationship did not change with CO 2 concentrations, but with age of the crop”
e1“Rooting of rice was linearly related to tillering”
Claim · model-written summary
Without adequate N, rice at high CO2 became inferior to ambient CO2 rice.
- Taxon
- riceOryza sativae0
- Treatment
- high CO 2e0
- Outcome
- became inferiore0
- Direction
- inferiore0
- Qualifier
- When adequate N was not suppliede0
- Comparator
- ambient CO 2e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When adequate N was not supplied, rice plants grown at high CO 2 became inferior to plants grown at ambient CO 2”
Claim · model-written summary
N uptake was higher at high CO2 until maximum tillering.
- Taxon
- riceOryza sativae1
- Treatment
- high CO 2e0
- Outcome
- N uptakee0
- Direction
- highere0
- Qualifier
- until maximum tilleringe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N uptake and fertilizer N recovery was higher in plants grown in high CO 2 until maximum tillering”
e1“Rooting of rice was linearly related to tillering”
Claim · model-written summary
Fertilizer N recovery was higher at high CO2 until maximum tillering.
- Taxon
- riceOryza sativae1
- Treatment
- high CO 2e0
- Outcome
- fertilizer N recoverye0
- Direction
- highere0
- Qualifier
- until maximum tilleringe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N uptake and fertilizer N recovery was higher in plants grown in high CO 2 until maximum tillering”
e1“Rooting of rice was linearly related to tillering”
Claim · model-written summary
N partitioning toward leaves decreased by 9% at high CO2.
- Taxon
- riceOryza sativae2
- Treatment
- high CO 2e1
- Outcome
- partitioning of N towards leavese0
- Direction
- decreasede0
- Value
- 9%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the partitioning of N towards leaves decreased by 9%”
e1“N uptake and fertilizer N recovery was higher in plants grown in high CO 2 until maximum tillering”
e2“Rooting of rice was linearly related to tillering”
Claim · model-written summary
Larger root systems at high CO2 were related to increased N uptake.
- Taxon
- riceOryza sativae1
- Organ / stage
- root systeme0
- Outcome
- Increased N uptakee0
- Direction
- Increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased N uptake under high CO 2 environment was related to its larger root system”
e1“Rooting of rice was linearly related to tillering”
Claim · model-written summary
Increased unproductive tillering enlarged rice root systems.
- Taxon
- riceOryza sativae1
- Outcome
- larger root systeme0
- Qualifier
- increased unproductive tilleringe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“its larger root system , which was due to increased unproductive tillering”
e1“Rooting of rice was linearly related to tillering”
Claim · model-written summary
The authors recommend different rice management at high atmospheric CO2.
- Taxon
- riceOryza sativae0
- Outcome
- management of the rice crop grown at high atmospheric CO 2 should be different to that under current conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“management of the rice crop grown at high atmospheric CO 2 should be different to that under current conditions”
The same questions in other papers
co2 · nutrient: content · Oryza sativa (rice)Positive and negative results
25 papers in the same direction as this paper · 28 in the opposite direction
- negative
- negative
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See all 54 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.