Abstract
Water-saving and drought-resistant rice (WDR) has high a yield potential in drought. However, the photosynthetic adaptation mechanisms of WDR to drought and rehydration have yet to be conclusively determined. Hanyou 73 (HY73, WDR) and Huanghuazhan (HHZ, drought-sensitive cultivar) rice cultivars were subjected to drought stress and rewatering when the soil water potential was −180 KPa in the booting stage. The leaf physiological characteristics were dynamically determined at 0 KPa, −30 KPa, −70 KPa, −180 KPa, the first, the fifth, and the tenth day after rewatering. It was found that the maximum net photosynthetic rate (Amax) and light saturation point were decreased under drought conditions in both cultivars. The change in dark respiration rate (Rd) in HY73 was not significant, but was markedly different in HHZ. After rewatering, the photosynthetic parameters of HY73 completely returned to the initial state, while the indices in HHZ did not recover. The antioxidant enzyme activities and osmoregulatory substance levels increased with worsening drought conditions and decreased with rewatering duration. HY73 had higher peroxidase (POD) activity as well as proline levels, and lower catalase (CAT) activity, ascorbate peroxidase (APX) activity, malondialdehyde (MDA) level, and soluble protein (SP) content during all of the assessment periods compared with HHZ. In addition, Amax was markedly negatively correlated with superoxide dismutase (SOD), POD, CAT, and SP in HY73 (p < 0.001), while in HHZ, it was negatively correlated with SOD, CAT, APX, MDA, Pro, and SP, and positively correlated with Rd (p < 0.001). These results suggest that WDR has a more simplified adaptation mechanism to protect photosynthetic apparatus from damage in drought and rehydration compared with drought-sensitive cultivars. The high POD activity and great SP content would be considered as important physiological bases to maintain high photosynthetic production potential in WDR.
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Claims 16
Claim · model-written summary
Drought decreased maximum net photosynthetic rate in both cultivars.
- Taxon
- rice
Oryza sativat0 - Treatment
- drought conditionse0
- Outcome
- maximum net photosynthetic rate (Amax)e0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the maximum net photosynthetic rate (Amax) and light saturation point were decreased under drought conditions in both cultivars”
t0“Rice”
Claim · model-written summary
Drought decreased light saturation point in both cultivars.
- Taxon
- riceOryza sativat0
- Treatment
- drought conditionse0
- Outcome
- light saturation pointe0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the maximum net photosynthetic rate (Amax) and light saturation point were decreased under drought conditions in both cultivars”
t0“Rice”
Claim · model-written summary
Dark respiration rate changed nonsignificantly in HY73.
- Taxon
- riceOryza sativat0
- Material
- HY73e0
- Outcome
- dark respiration rate (Rd)e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The change in dark respiration rate (Rd) in HY73 was not significant”
t0“Rice”
Claim · model-written summary
Dark respiration rate changed markedly in HHZ.
- Taxon
- riceOryza sativat0
- Material
- HHZe0
- Outcome
- dark respiration rate (Rd)e1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“but was markedly different in HHZ”
e1“The change in dark respiration rate (Rd) in HY73 was not significant, but was markedly different in HHZ”
t0“Rice”
Claim · model-written summary
After rewatering, HY73 photosynthetic parameters fully recovered.
- Taxon
- riceOryza sativat0
- Material
- HY73e0
- Treatment
- rewateringe0
- Outcome
- photosynthetic parameterse0
- Direction
- returnede0
- Comparator
- initial statee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“After rewatering, the photosynthetic parameters of HY73 completely returned to the initial state”
t0“Rice”
Claim · model-written summary
After rewatering, HHZ photosynthetic indices did not recover.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“while the indices in HHZ did not recover”
e1“After rewatering, the photosynthetic parameters of HY73 completely returned to the initial state, while the indices in HHZ did not recover”
t0“Rice”
Claim · model-written summary
Antioxidant enzyme activities and osmoregulatory substance levels rose as drought worsened.
- Taxon
- riceOryza sativat0
- Treatment
- worsening drought conditionse0
- Outcome
- antioxidant enzyme activities and osmoregulatory substance levelse0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The antioxidant enzyme activities and osmoregulatory substance levels increased with worsening drought conditions”
t0“Rice”
Claim · model-written summary
Antioxidant enzyme activities and osmoregulatory substance levels declined with longer rewatering.
- Taxon
- riceOryza sativat0
- Treatment
- rewatering duratione0
- Outcome
- antioxidant enzyme activities and osmoregulatory substance levelse1
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreased with rewatering duration”
e1“The antioxidant enzyme activities and osmoregulatory substance levels increased with worsening drought conditions and decreased with rewatering duration.”
t0“Rice”
Claim · model-written summary
HY73 had higher POD activity and proline levels than HHZ.
- Taxon
- riceOryza sativat0
- Material
- HY73e0
- Outcome
- peroxidase (POD) activity as well as proline levelse0
- Direction
- highere0
- Comparator
- HHZe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“HY73 had higher peroxidase (POD) activity as well as proline levels, and lower catalase (CAT) activity, ascorbate peroxidase (APX) activity, malondialdehyde (MDA) level, and soluble protein (SP) content during all of the assessment periods compared with HHZ”
t0“Rice”
Claim · model-written summary
HY73 had lower CAT and APX activities than HHZ throughout assessment.
- Taxon
- riceOryza sativat0
- Material
- HY73e0
- Outcome
- catalase (CAT) activity, ascorbate peroxidase (APX) activitye0
- Direction
- lowere0
- Comparator
- HHZe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“HY73 had higher peroxidase (POD) activity as well as proline levels, and lower catalase (CAT) activity, ascorbate peroxidase (APX) activity, malondialdehyde (MDA) level, and soluble protein (SP) content during all of the assessment periods compared with HHZ”
t0“Rice”
Claim · model-written summary
HY73 had lower MDA level and soluble protein content than HHZ throughout assessment.
- Taxon
- riceOryza sativat0
- Material
- HY73e0
- Outcome
- malondialdehyde (MDA) level, and soluble protein (SP) contente0
- Direction
- lowere0
- Comparator
- HHZe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“HY73 had higher peroxidase (POD) activity as well as proline levels, and lower catalase (CAT) activity, ascorbate peroxidase (APX) activity, malondialdehyde (MDA) level, and soluble protein (SP) content during all of the assessment periods compared with HHZ”
t0“Rice”
Claim · model-written summary
In HY73, Amax correlated negatively with SOD, POD, CAT, and SP.
- Taxon
- riceOryza sativat0
- Material
- HY73e0
- Gene
- superoxide dismutase (SOD), POD, CAT, and SPe0
- Outcome
- Amaxe0
- Direction
- negatively correlatede0
- Qualifier
- p < 0.001e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Amax was markedly negatively correlated with superoxide dismutase (SOD), POD, CAT, and SP in HY73 (p < 0.001)”
t0“Rice”
Claim · model-written summary
In HHZ, Amax correlated negatively with SOD, CAT, APX, MDA, Pro, and SP.
- Taxon
- riceOryza sativat0
- Material
- HHZe0
- Outcome
- Amaxe1
- Direction
- negatively correlatede0
- Qualifier
- SOD, CAT, APX, MDA, Pro, and SPe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in HHZ, it was negatively correlated with SOD, CAT, APX, MDA, Pro, and SP”
e1“Amax was markedly negatively correlated with superoxide dismutase (SOD), POD, CAT, and SP in HY73 (p < 0.001), while in HHZ, it was negatively correlated with SOD, CAT, APX, MDA, Pro, and SP, and positively correlated with Rd (p < 0.001).”
t0“Rice”
Claim · model-written summary
In HHZ, Amax correlated positively with Rd.
- Taxon
- riceOryza sativat0
- Material
- HHZe1
- Outcome
- Amaxe1
- Direction
- positively correlatede0
- Qualifier
- p < 0.001e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“positively correlated with Rd (p < 0.001)”
e1“Amax was markedly negatively correlated with superoxide dismutase (SOD), POD, CAT, and SP in HY73 (p < 0.001), while in HHZ, it was negatively correlated with SOD, CAT, APX, MDA, Pro, and SP, and positively correlated with Rd (p < 0.001).”
t0“Rice”
Claim · model-written summary
The authors infer a simpler drought and rehydration adaptation mechanism in WDR.
- Taxon
- riceOryza sativat0
- Material
- WDRe0
- Outcome
- protect photosynthetic apparatus from damagee0
- Qualifier
- more simplified adaptation mechanisme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“WDR has a more simplified adaptation mechanism to protect photosynthetic apparatus from damage in drought and rehydration compared with drought-sensitive cultivars”
t0“Rice”
Claim · model-written summary
The authors consider high POD activity and SP content physiological bases of photosynthetic production potential in WDR.
- Taxon
- riceOryza sativat0
- Material
- WDRe0
- Outcome
- high photosynthetic production potentiale0
- Qualifier
- high POD activity and great SP contente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The high POD activity and great SP content would be considered as important physiological bases to maintain high photosynthetic production potential in WDR”
t0“Rice”
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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.