Abstract
Alkaline stress (high pH) severely damages root cells, and consequently, inhibits rice (Oryza sativa L.) seedling growth. In this study, we demonstrate the accumulation of reactive oxygen species (ROS) in root cells under alkaline stress. Seedlings of two rice cultivars with different alkaline tolerances, ‘Dongdao-4’ (moderately alkaline-tolerant) and ‘Jiudao-51’ (alkaline-sensitive), were subjected to alkaline stress simulated by 15 mM sodium carbonate (Na2CO3). Alkaline stress greatly reduced seedling survival rate, shoot and root growth, and root vigor. Moreover, severe root cell damage was observed under alkaline stress, as shown by increased membrane injury, malondialdehyde accumulation, and Evan’s Blue staining. The expression of the cell death-related genes OsKOD1, OsHsr203j, OsCP1, and OsNAC4 was consistently upregulated, while that of a cell death-suppressor gene, OsBI1, was downregulated. Analysis of the ROS contents revealed that alkaline stress induced a marked accumulation of superoxide anions (O2-) and hydrogen peroxide (H2O2) in rice roots. The application of procyanidins (a potent antioxidant) to rice seedlings 24 h prior to alkaline treatment significantly alleviated alkalinity-induced root damage and promoted seedling growth inhibition, which were concomitant with reduced ROS accumulation. These results suggest that root cell damage, and consequently growth inhibition, of rice seedlings under alkaline stress is closely associated with ROS accumulation. The antioxidant activity of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase increased under alkaline stress in the roots, probably in response to the cellular damage induced by oxidative stress. However, this response mechanism may be overwhelmed by the excess ROS accumulation observed under stress, resulting in oxidative damage to root cells. Our findings provide physiological insights into the molecular mechanisms of alkalinity-induced damage to root cells, and will contribute to the improvement of alkaline stress tolerance in rice plants.
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Claims 15
Claim · model-written summary
Alkaline stress reduced seedling survival rate and shoot and root growth in rice.
- Taxon
- rice
Oryza sativat1 - Treatment
- Alkaline stresse1
- Outcome
- seedling survival rate, shoot and root growthe1
- Direction
- reducede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Alkaline stress greatly reduced seedling survival rate, shoot and root growth, and root vigor”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Alkaline stress reduced root vigor in rice.
- Taxon
- riceOryza sativat1
- Treatment
- Alkaline stresse1
- Outcome
- root vigore1
- Direction
- reducede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Alkaline stress greatly reduced seedling survival rate, shoot and root growth, and root vigor”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Severe root cell damage was observed in rice under alkaline stress.
- Taxon
- riceOryza sativat1
- Outcome
- root cell damagee2
- Qualifier
- severee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“severe root cell damage was observed under alkaline stress”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Alkaline stress increased membrane injury and malondialdehyde accumulation in rice roots.
- Taxon
- riceOryza sativat1
- Treatment
- alkaline stresse2
- Outcome
- membrane injury, malondialdehyde accumulatione3
- Direction
- increasede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“severe root cell damage was observed under alkaline stress”
e3“as shown by increased membrane injury, malondialdehyde accumulation, and Evan’s Blue staining”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Alkaline stress increased Evan’s Blue staining in rice roots.
- Taxon
- riceOryza sativat1
- Treatment
- alkaline stresse2
- Outcome
- Evan’s Blue staininge3
- Direction
- increasede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“severe root cell damage was observed under alkaline stress”
e3“as shown by increased membrane injury, malondialdehyde accumulation, and Evan’s Blue staining”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Alkaline stress upregulated expression of OsKOD1, OsHsr203j and OsCP1 in rice.
- Taxon
- riceOryza sativat1
- Treatment
- alkaline stresse2
- Gene
- OsKOD1, OsHsr203j, OsCP1e4
- Outcome
- expressione4
- Direction
- upregulatede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“severe root cell damage was observed under alkaline stress”
e4“The expression of the cell death-related genes OsKOD1, OsHsr203j, OsCP1, and OsNAC4 was consistently upregulated, while that of a cell death-suppressor gene, OsBI1, was downregulated”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Alkaline stress upregulated expression of OsNAC4 in rice.
- Taxon
- riceOryza sativat1
- Treatment
- alkaline stresse2
- Gene
- OsNAC4e4
- Outcome
- expressione4
- Direction
- upregulatede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“severe root cell damage was observed under alkaline stress”
e4“The expression of the cell death-related genes OsKOD1, OsHsr203j, OsCP1, and OsNAC4 was consistently upregulated, while that of a cell death-suppressor gene, OsBI1, was downregulated”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Alkaline stress downregulated expression of the cell death-suppressor gene OsBI1 in rice.
- Taxon
- riceOryza sativat1
- Treatment
- alkaline stresse2
- Gene
- OsBI1e4
- Outcome
- expressione4
- Direction
- downregulatede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“severe root cell damage was observed under alkaline stress”
e4“The expression of the cell death-related genes OsKOD1, OsHsr203j, OsCP1, and OsNAC4 was consistently upregulated, while that of a cell death-suppressor gene, OsBI1, was downregulated”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Alkaline stress increased superoxide anion and hydrogen peroxide accumulation in rice roots.
- Taxon
- riceOryza sativat1
- Organ / stage
- rootse5
- Treatment
- alkaline stresse5
- Outcome
- superoxide anions (O2-) and hydrogen peroxide (H2O2)e5
- Direction
- increaseinferrede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Analysis of the ROS contents revealed that alkaline stress induced a marked accumulation of superoxide anions (O2-) and hydrogen peroxide (H2O2) in rice roots”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Procyanidins significantly alleviated alkalinity-induced root damage in rice seedlings.
- Taxon
- riceOryza sativat1
- Treatment
- procyanidinse6
- Outcome
- root damagee6
- Direction
- alleviatede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“The application of procyanidins (a potent antioxidant) to rice seedlings 24 h prior to alkaline treatment significantly alleviated alkalinity-induced root damage and promoted seedling growth inhibition”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Procyanidins promoted seedling growth inhibition under alkaline treatment, as the abstract states.
- Taxon
- riceOryza sativat1
- Treatment
- procyanidinse6
- Outcome
- seedling growth inhibitione6
- Direction
- promotede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Schema note from the model: Abstract wording "promoted seedling growth inhibition" is copied as written; it may intend alleviated growth inhibition. Check the full text.
Verbatim
e6“The application of procyanidins (a potent antioxidant) to rice seedlings 24 h prior to alkaline treatment significantly alleviated alkalinity-induced root damage and promoted seedling growth inhibition”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Procyanidins reduced ROS accumulation in rice roots under alkaline stress.
- Taxon
- riceOryza sativat1
- Treatment
- procyanidinse6
- Outcome
- ROS accumulatione7
- Direction
- reducede7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“The application of procyanidins (a potent antioxidant) to rice seedlings 24 h prior to alkaline treatment significantly alleviated alkalinity-induced root damage and promoted seedling growth inhibition”
e7“which were concomitant with reduced ROS accumulation”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Antioxidant activity of superoxide dismutase, catalase and peroxidase increased under alkaline stress in rice roots.
- Taxon
- riceOryza sativat1
- Organ / stage
- rootse1
- Treatment
- alkaline stresse1
- Outcome
- antioxidant activity of superoxide dismutase, catalase, peroxidasee1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The antioxidant activity of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase increased under alkaline stress in the roots”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Ascorbate peroxidase activity increased under alkaline stress in rice roots.
- Taxon
- riceOryza sativat1
- Organ / stage
- rootse1
- Treatment
- alkaline stresse1
- Outcome
- ascorbate peroxidasee1
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The antioxidant activity of superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase increased under alkaline stress in the roots”
t1“Rice (Oryza sativa L.)”
Claim · model-written summary
Excess ROS accumulation may overwhelm the antioxidant response and cause oxidative damage to root cells.
- Taxon
- riceOryza sativat1
- Compound
- ROSe1
- Outcome
- oxidative damage to root cellse1
- Qualifier
- this response mechanism may be overwhelmede1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“However, this response mechanism may be overwhelmed by the excess ROS accumulation observed under stress, resulting in oxidative damage to root cells”
t1“Rice (Oryza sativa L.)”
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See all 17 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.