Abstract
Iron (Fe) toxicity is one of the most frequent abiotic stresses in rice, as it affects from 15% to 30% of the total production. Brassinosteroids (BRs), including 24-epibrassinolide (EBR), regulate ion homeostasis and improve the antioxidant system. The aim of this research was to determine whether EBR can contribute to the tolerance of rice plants exposed to Fe toxicity and to evaluate the possible effect on anatomical characteristics, nutrient concentrations, the antioxidant system, and gas exchange. The experiment was randomized with four treatments, two with different concentrations of Fe (250 and 6250 μM, control and toxicity, respectively) and these were either supplied with EBR or not (0 and 10 nM EBR, described as -EBR and +EBR, respectively). Treating plants grown under Fe toxic conditions with EBR caused an 70% increase in root aerenchyma area, compared to plants without steroid treatment. Our results revealed that EBR treatment could mitigate the deleterious effects of Fe toxicity in rice plants, by modulating the aerenchyma area, which contributes to the formation of an oxidative barrier and reduce the Fe mobilization at the root surface. Plants that were exposed to Fe toxic concentrations and treated with EBR showed (1) an increase in the enzyme activities of superoxide dismutase, catalase, ascorbate peroxidase and peroxidase, (2) mitigation of oxidative damage and (3) increased scavenging of reactive oxygen species. Finally, EBR alleviated the negative impacts induced by excess Fe on the net photosynthetic rate and the instantaneous carboxylation efficiency. These benefits were directly related to higher electron transport and stomatal density and indirectly linked to the protection mechanism exercised by the antioxidant enzymes on photosynthetic machinery. We conclude that EBR is able to confer tolerance to Fe toxicity in rice plants.
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Claims 8
Claim · model-written summary
EBR increased root aerenchyma area by 70% under iron toxicity.
- Taxon
- rice
Oryza sativat0 - Treatment
- EBRe0
- Outcome
- root aerenchyma areae0
- Direction
- increasee0
- Value
- 70%e0
- Comparator
- plants without steroid treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Treating plants grown under Fe toxic conditions with EBR caused an 70% increase in root aerenchyma area, compared to plants without steroid treatment”
t0“rice”
Claim · model-written summary
EBR increased antioxidant enzyme activities under iron toxicity.
- Taxon
- riceOryza sativat0
- Treatment
- EBRe0
- Outcome
- enzyme activities of superoxide dismutase, catalase, ascorbate peroxidase and peroxidasee0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants that were exposed to Fe toxic concentrations and treated with EBR showed (1) an increase in the enzyme activities of superoxide dismutase, catalase, ascorbate peroxidase and peroxidase”
t0“rice”
Claim · model-written summary
EBR mitigated oxidative damage under iron toxicity.
- Taxon
- riceOryza sativat0
- Treatment
- EBRe0
- Outcome
- oxidative damagee0
- Direction
- mitigatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants that were exposed to Fe toxic concentrations and treated with EBR showed (1) an increase in the enzyme activities of superoxide dismutase, catalase, ascorbate peroxidase and peroxidase, (2) mitigation of oxidative damage”
t0“rice”
Claim · model-written summary
EBR increased reactive oxygen species scavenging under iron toxicity.
- Taxon
- riceOryza sativat0
- Treatment
- EBRe0
- Outcome
- scavenging of reactive oxygen speciese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Plants that were exposed to Fe toxic concentrations and treated with EBR showed (1) an increase in the enzyme activities of superoxide dismutase, catalase, ascorbate peroxidase and peroxidase, (2) mitigation of oxidative damage and (3) increased scavenging of reactive oxygen species”
t0“rice”
Claim · model-written summary
EBR alleviated the effects of excess iron on photosynthetic rate and carboxylation efficiency.
- Taxon
- riceOryza sativat0
- Treatment
- EBRe0
- Outcome
- net photosynthetic rate and the instantaneous carboxylation efficiencye0
- Direction
- alleviatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“EBR alleviated the negative impacts induced by excess Fe on the net photosynthetic rate and the instantaneous carboxylation efficiency”
t0“rice”
Claim · model-written summary
Higher electron transport and stomatal density were linked to the benefits of EBR.
- Taxon
- riceOryza sativat0
- Treatment
- Brassinosteroidst0
- Outcome
- electron transport and stomatal densitye0
- Direction
- highere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These benefits were directly related to higher electron transport and stomatal density”
t0“Brassinosteroids trigger tolerance to iron toxicity in rice”
Claim · model-written summary
The authors attributed reduced iron mobilization to aerenchyma-linked oxidative barrier formation.
- Taxon
- riceOryza sativat0
- Organ / stage
- roote0
- Outcome
- Fe mobilization at the root surfacee0
- Qualifier
- formation of an oxidative barriere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“modulating the aerenchyma area, which contributes to the formation of an oxidative barrier and reduce the Fe mobilization at the root surface”
t0“rice”
Claim · model-written summary
The authors linked protection of photosynthetic machinery to antioxidant enzymes.
- Taxon
- riceOryza sativat0
- Outcome
- photosynthetic machinerye0
- Qualifier
- protection mechanism exercised by the antioxidant enzymese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“protection mechanism exercised by the antioxidant enzymes on photosynthetic machinery”
t0“rice”
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24-epi-brassinolide · physiology: photosynthesis · Oryza sativa (rice)Results agree
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24-epi-brassinolide · physiology: oxidative · Oryza sativa (rice)Results agree
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1 paper more in this group
See all 5 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.