Abstract
In tomato (Lycopersicon esculentum L.), the effects of combined drought (D) and high temperature (HT) stress during the flowering stage had not been studied in detail. Therefore, this study was conducted with an objective of quantifying the effects of foliar spray of melatonin under individual and combined drought and HT stress. At flowering stage, D stress was imposed through withholding irrigation, while HT stress was imposed through exposing the plants to ambient temperature (AT) along with an increase of +5 °C. Under D + HT, plants were first subjected to drought followed by a + 5 °C increase in AT. The duration of individual or combined stress was ten days. At 80% available soil moisture, 100 µM melatonin was sprayed on D, HT, or D + HT treated plants. Among the stresses, D + HT stress increased the thylakoid membrane damage and decreased the photosynthetic rate and fruit yield more than D or HT stress. Foliar spray of 100 µM melatonin produced decreased thylakoid membrane damage [D: 31%, HT: 26%, and D + HT: 18%] and increased antioxidant enzyme, viz., superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase, activity over stress-control plants. The photosynthetic rate [D: 24%, HT: 22%, and D + HT: 19%] and fruit yield [D: 32%, HT: 23%, and D + HT: 16%] were increased over stress-control plants. Hence, it is evident that the increased photosynthetic rate and fruit yield in D + HT and 100 µM melatonin-sprayed plants may be associated with an increased antioxidant defense system. Melatonin as a novel biostimulator has a great potential in scavenging free radicals through increased antioxidant activity, which shields the photosynthetic membrane from damage and therefore helps in stress mitigation.
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Claims 14
Claim · model-written summary
Combined drought and heat increased thylakoid membrane damage more than either stress alone.
- Taxon
- tomato
Solanum lycopersicumt0 - Treatment
- D + HT stresse0
- Outcome
- thylakoid membrane damagee0
- Direction
- increasede0
- Comparator
- D or HT stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among the stresses, D + HT stress increased the thylakoid membrane damage and decreased the photosynthetic rate and fruit yield more than D or HT stress.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Combined drought and heat decreased photosynthetic rate more than either stress alone.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- D + HT stresse0
- Outcome
- photosynthetic ratee0
- Direction
- decreasede0
- Comparator
- D or HT stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among the stresses, D + HT stress increased the thylakoid membrane damage and decreased the photosynthetic rate and fruit yield more than D or HT stress.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Combined drought and heat decreased fruit yield more than either stress alone.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- D + HT stresse0
- Outcome
- fruit yielde0
- Direction
- decreasede0
- Comparator
- D or HT stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Among the stresses, D + HT stress increased the thylakoid membrane damage and decreased the photosynthetic rate and fruit yield more than D or HT stress.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Melatonin reduced membrane damage by 31% under drought.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- 100 µM melatonine0
- Outcome
- thylakoid membrane damagee0
- Direction
- decreasede0
- Value
- 31%e0
- Qualifier
- De0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar spray of 100 µM melatonin produced decreased thylakoid membrane damage [D: 31%, HT: 26%, and D + HT: 18%] and increased antioxidant enzyme”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Melatonin reduced membrane damage by 26% under heat.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- 100 µM melatonine0
- Outcome
- thylakoid membrane damagee0
- Direction
- decreasede0
- Value
- 26%e0
- Qualifier
- HTe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar spray of 100 µM melatonin produced decreased thylakoid membrane damage [D: 31%, HT: 26%, and D + HT: 18%] and increased antioxidant enzyme”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Melatonin reduced membrane damage by 18% under combined stress.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- 100 µM melatonine0
- Outcome
- thylakoid membrane damagee0
- Direction
- decreasede0
- Value
- 18%e0
- Qualifier
- D + HTe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar spray of 100 µM melatonin produced decreased thylakoid membrane damage [D: 31%, HT: 26%, and D + HT: 18%] and increased antioxidant enzyme”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Melatonin increased activities of five antioxidant enzymes over stress controls.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- melatonint1
- Outcome
- superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase, activitye0
- Direction
- increasede0
- Comparator
- stress-control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased antioxidant enzyme, viz., superoxide dismutase, catalase, peroxidase, ascorbate peroxidase, and glutathione reductase, activity over stress-control plants.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Melatonin increased photosynthetic rate by 24% under drought.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- melatonint1
- Outcome
- photosynthetic ratee0
- Direction
- increasede0
- Value
- 24%e0
- Qualifier
- De0
- Comparator
- stress-control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The photosynthetic rate [D: 24%, HT: 22%, and D + HT: 19%] and fruit yield [D: 32%, HT: 23%, and D + HT: 16%] were increased over stress-control plants.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Melatonin increased photosynthetic rate by 22% under heat.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- melatonint1
- Outcome
- photosynthetic ratee0
- Direction
- increasede0
- Value
- 22%e0
- Qualifier
- HTe0
- Comparator
- stress-control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The photosynthetic rate [D: 24%, HT: 22%, and D + HT: 19%] and fruit yield [D: 32%, HT: 23%, and D + HT: 16%] were increased over stress-control plants.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Melatonin increased photosynthetic rate by 19% under combined stress.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- melatonint1
- Outcome
- photosynthetic ratee0
- Direction
- increasede0
- Value
- 19%e0
- Qualifier
- D + HTe0
- Comparator
- stress-control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The photosynthetic rate [D: 24%, HT: 22%, and D + HT: 19%] and fruit yield [D: 32%, HT: 23%, and D + HT: 16%] were increased over stress-control plants.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Melatonin increased fruit yield by 32% under drought.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- melatonint1
- Outcome
- fruit yielde0
- Direction
- increasede0
- Value
- 32%e0
- Qualifier
- De0
- Comparator
- stress-control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The photosynthetic rate [D: 24%, HT: 22%, and D + HT: 19%] and fruit yield [D: 32%, HT: 23%, and D + HT: 16%] were increased over stress-control plants.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Melatonin increased fruit yield by 23% under heat.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- melatonint1
- Outcome
- fruit yielde0
- Direction
- increasede0
- Value
- 23%e0
- Qualifier
- HTe0
- Comparator
- stress-control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The photosynthetic rate [D: 24%, HT: 22%, and D + HT: 19%] and fruit yield [D: 32%, HT: 23%, and D + HT: 16%] were increased over stress-control plants.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
Melatonin increased fruit yield by 16% under combined stress.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- melatonint1
- Outcome
- fruit yielde0
- Direction
- increasede0
- Value
- 16%e0
- Qualifier
- D + HTe0
- Comparator
- stress-control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The photosynthetic rate [D: 24%, HT: 22%, and D + HT: 19%] and fruit yield [D: 32%, HT: 23%, and D + HT: 16%] were increased over stress-control plants.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
Claim · model-written summary
The authors associated improved photosynthesis and yield under combined stress and melatonin with antioxidant defenses.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- 100 µM melatonin-sprayede0
- Outcome
- increased photosynthetic rate and fruit yielde0
- Qualifier
- increased antioxidant defense systeme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the increased photosynthetic rate and fruit yield in D + HT and 100 µM melatonin-sprayed plants may be associated with an increased antioxidant defense system.”
t0“Tomato”
t1“Melatonin Decreases Negative Effects of Combined Drought and High Temperature Stresses through Enhanced Antioxidant Defense System in Tomato Leaves”
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