Abstract
Effects of water deficit and flooding stress on rice’s intrinsic water-use efficiency (iWUE) and how iWUE variations are linked to stress-induced physiological changes are poorly understood. Here, we proposed a model-based approach to analyze iWUE across datasets and its relationship with physiological changes, using only leaf gas exchange data and plant hydraulic vulnerability parameters. We applied this approach to a leaf gas exchange dataset of rice, measured during the post-stress period of water deficit and flooding experiments. Results show that water deficit and flooding stress decreased rice’s photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period, and that these physiological changes altered the relationship between photosynthetic rate and stomatal conductance, leading to an increase in iWUE. Nevertheless, improved iWUE cannot avoid the yield reduction. Interestingly, the stress-induced decrease in Vcmax25 was significantly correlated with the decline in Kmax. The Vcmax25-Kmax relationship was significantly different between the water deficit and flooding treatments, with the slope of the latter being closer to 1:1. Model predicts that stress-induced disproportionate Vcmax25-Kmax co-reduction improved iWUE while maintaining a relatively high intercellular to atmosphere CO2 concentration ratio; this may represent optimal coordination between photosynthetic and hydraulic traits in response to stress. Our work has important implications for using leaf gas exchange data to diagnose variations in iWUE, and for improving our understanding of crop physiological responses to environmental stresses.
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Claims 8
Claim · model-written summary
Water deficit and flooding stress decreased rice photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period.
- Taxon
- rice
Oryza sativae1 - Treatment
- water deficit and flooding stresse1
- Outcome
- photosynthetic capacity (Vcmax25) and water transport capacity (Kmax)e1
- Direction
- decreasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“water deficit and flooding stress decreased rice’s photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period”
Claim · model-written summary
Water deficit and flooding stress increased rice intrinsic water-use efficiency (iWUE) by altering the relation between photosynthetic rate and stomatal conductance.
- Taxon
- riceOryza sativae1
- Treatment
- water deficit and flooding stresse1
- Outcome
- iWUEe2
- Direction
- increasee2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“water deficit and flooding stress decreased rice’s photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period”
e2“these physiological changes altered the relationship between photosynthetic rate and stomatal conductance, leading to an increase in iWUE”
Claim · model-written summary
Improved iWUE did not avoid a reduction in rice yield under these stresses.
- Taxon
- riceOryza sativae1
- Outcome
- yielde3
- Direction
- reductione3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“water deficit and flooding stress decreased rice’s photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period”
e3“Nevertheless, improved iWUE cannot avoid the yield reduction”
Claim · model-written summary
The stress-induced decrease in Vcmax25 was significantly correlated with the decline in Kmax in rice.
- Taxon
- riceOryza sativae1
- Treatment
- stress-inducede4
- Outcome
- Kmaxe4
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“water deficit and flooding stress decreased rice’s photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period”
e4“the stress-induced decrease in Vcmax25 was significantly correlated with the decline in Kmax”
Claim · model-written summary
The Vcmax25-Kmax relationship differed significantly between the water deficit and flooding treatments.
- Taxon
- riceOryza sativae1
- Treatment
- water deficit and flooding treatmentse5
- Outcome
- Vcmax25-Kmax relationshipe5
- Direction
- differente5
- Comparator
- water deficite5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“water deficit and flooding stress decreased rice’s photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period”
e5“The Vcmax25-Kmax relationship was significantly different between the water deficit and flooding treatments”
Claim · model-written summary
In rice under flooding, the slope of the Vcmax25-Kmax relationship is closer to 1:1.
- Taxon
- riceOryza sativae1
- Treatment
- flooding treatmentse5
- Outcome
- slopee6
- Qualifier
- closer to 1:1e6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“water deficit and flooding stress decreased rice’s photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period”
e5“The Vcmax25-Kmax relationship was significantly different between the water deficit and flooding treatments”
e6“with the slope of the latter being closer to 1:1”
Claim · model-written summary
Model predicts that stress-induced disproportionate Vcmax25-Kmax co-reduction improves rice iWUE.
- Taxon
- riceOryza sativae1
- Treatment
- stress-induced disproportionate Vcmax25-Kmax co-reductione7
- Outcome
- iWUEe7
- Direction
- improvede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“water deficit and flooding stress decreased rice’s photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period”
e7“Model predicts that stress-induced disproportionate Vcmax25-Kmax co-reduction improved iWUE while maintaining a relatively high intercellular to atmosphere CO2 concentration ratio”
Claim · model-written summary
Model predicts that the same Vcmax25-Kmax co-reduction keeps the intercellular to atmosphere CO2 concentration ratio relatively high in rice.
- Taxon
- riceOryza sativae1
- Treatment
- stress-induced disproportionate Vcmax25-Kmax co-reductione7
- Outcome
- intercellular to atmosphere CO2 concentration ratioe7
- Direction
- maintaining a relatively highe7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“water deficit and flooding stress decreased rice’s photosynthetic capacity (Vcmax25) and water transport capacity (Kmax) during the post-stress period”
e7“Model predicts that stress-induced disproportionate Vcmax25-Kmax co-reduction improved iWUE while maintaining a relatively high intercellular to atmosphere CO2 concentration ratio”
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See all 96 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.