Abstract
Elevated temperatures severely affect plant growth, reducing yield and quality. Melatonin (MT), a plant biomolecule, is known to enhance stress tolerance, but its role in heat resistance and underlying mechanisms require further exploration. This study investigates MT’s regulatory effects on chlorophyll metabolism and photosynthesis in tomato seedlings under high-temperature stress (40°C). Tomato seedlings treated with 100 μmol MT showed improved physiological and photosynthetic performance under heat stress. MT application increased osmolytes (proline and soluble sugar), enhanced antioxidant enzyme activities [catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX)], and reduced oxidative damage markers (H 2 O 2 , O 2 − , malondialdehyde, and conductivity). Photosynthetic parameters, including key enzyme activities [sedoheptulose-1,7-bisphosphatase (SBPase), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), and NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPDH)], photochemical efficiency [Fv/Fm and Y(II)], and photochemical quenching (Qp), were significantly improved, restoring the OJIP curve and enhancing photosynthesis. MT also regulated chlorophyll metabolism by promoting synthesis [increasing chlorophyll a and b , 5-aminolevulinic acid (ALA), Mg-protoporphyrin (Mg Proto), and protochlorophyllide (Pchlide) levels] and upregulating synthesis genes ( SlHEMA1 , SlPORB , SlPORC , and SlCHLI ) while inhibiting degradation genes ( SlCLH1 , SlCLH2 , SlPAO , SlPPH , and SlRCCR ). These findings demonstrate that MT enhances tomato heat tolerance by protecting chlorophyll metabolism and photosynthesis, offering a theoretical basis for improving crop resilience to heat stress.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 15
Claim · model-written summary
Melatonin at 100 μmol improved physiological and photosynthetic performance of tomato seedlings under heat stress.
- Taxon
- tomato
Solanum lycopersicumt0 - Treatment
- 100 μmol MTe1
- Outcome
- physiological and photosynthetic performancee1
- Direction
- improvede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e1“Tomato seedlings treated with 100 μmol MT showed improved physiological and photosynthetic performance under heat stress”
Claim · model-written summary
Melatonin application increased osmolytes (proline and soluble sugar) in heat-stressed tomato seedlings.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MT applicatione2
- Outcome
- osmolytes (proline and soluble sugar)e2
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e2“MT application increased osmolytes (proline and soluble sugar)”
Claim · model-written summary
Melatonin application enhanced antioxidant enzyme activities (CAT, POD, APX) in tomato seedlings.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MT applicatione2
- Outcome
- antioxidant enzyme activitiese3
- Direction
- enhancede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e2“MT application increased osmolytes (proline and soluble sugar)”
e3“enhanced antioxidant enzyme activities [catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX)]”
Claim · model-written summary
Melatonin application reduced H2O2, O2−, and malondialdehyde as oxidative damage markers.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MT applicatione2
- Outcome
- H 2 O 2 , O 2 − , malondialdehydee4
- Direction
- reducede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e2“MT application increased osmolytes (proline and soluble sugar)”
e4“reduced oxidative damage markers (H 2 O 2 , O 2 − , malondialdehyde, and conductivity)”
Claim · model-written summary
Melatonin application reduced conductivity as an oxidative damage marker in tomato seedlings.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MT applicatione2
- Outcome
- conductivitye4
- Direction
- reducede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e2“MT application increased osmolytes (proline and soluble sugar)”
e4“reduced oxidative damage markers (H 2 O 2 , O 2 − , malondialdehyde, and conductivity)”
Claim · model-written summary
Melatonin significantly improved key photosynthetic enzyme activities (SBPase, Rubisco, NADP-GAPDH) in tomato seedlings under heat stress.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MTe1
- Outcome
- key enzyme activitiese5
- Direction
- improvede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e1“Tomato seedlings treated with 100 μmol MT showed improved physiological and photosynthetic performance under heat stress”
e5“Photosynthetic parameters, including key enzyme activities [sedoheptulose-1,7-bisphosphatase (SBPase), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), and NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPDH)], photochemical efficiency [Fv/Fm and Y(II)], and photochemical quenching (Qp), were significantly improved, restoring the OJIP curve and enhancing photosynthesis”
Claim · model-written summary
Melatonin significantly improved photochemical efficiency (Fv/Fm and Y(II)) in tomato seedlings under heat stress.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MTe1
- Outcome
- photochemical efficiencye5
- Direction
- improvede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e1“Tomato seedlings treated with 100 μmol MT showed improved physiological and photosynthetic performance under heat stress”
e5“Photosynthetic parameters, including key enzyme activities [sedoheptulose-1,7-bisphosphatase (SBPase), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), and NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPDH)], photochemical efficiency [Fv/Fm and Y(II)], and photochemical quenching (Qp), were significantly improved, restoring the OJIP curve and enhancing photosynthesis”
Claim · model-written summary
Melatonin significantly improved photochemical quenching (Qp) in tomato seedlings under heat stress.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MTe1
- Outcome
- photochemical quenching (Qp)e5
- Direction
- improvede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e1“Tomato seedlings treated with 100 μmol MT showed improved physiological and photosynthetic performance under heat stress”
e5“Photosynthetic parameters, including key enzyme activities [sedoheptulose-1,7-bisphosphatase (SBPase), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), and NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPDH)], photochemical efficiency [Fv/Fm and Y(II)], and photochemical quenching (Qp), were significantly improved, restoring the OJIP curve and enhancing photosynthesis”
Claim · model-written summary
Melatonin enhanced photosynthesis and restored the OJIP curve in tomato seedlings under heat stress.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MTe1
- Outcome
- photosynthesise5
- Direction
- enhancinge5
- Qualifier
- restoring the OJIP curvee5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e1“Tomato seedlings treated with 100 μmol MT showed improved physiological and photosynthetic performance under heat stress”
e5“Photosynthetic parameters, including key enzyme activities [sedoheptulose-1,7-bisphosphatase (SBPase), ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), and NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (NADP-GAPDH)], photochemical efficiency [Fv/Fm and Y(II)], and photochemical quenching (Qp), were significantly improved, restoring the OJIP curve and enhancing photosynthesis”
Claim · model-written summary
Melatonin increased chlorophyll a and b in tomato seedlings.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MTe6
- Outcome
- chlorophyll a and be6
- Direction
- increasinge6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e6“MT also regulated chlorophyll metabolism by promoting synthesis [increasing chlorophyll a and b , 5-aminolevulinic acid (ALA), Mg-protoporphyrin (Mg Proto), and protochlorophyllide (Pchlide) levels]”
Claim · model-written summary
Melatonin increased 5-aminolevulinic acid, Mg-protoporphyrin and protochlorophyllide levels in tomato seedlings.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MTe6
- Outcome
- 5-aminolevulinic acid (ALA), Mg-protoporphyrin (Mg Proto), and protochlorophyllide (Pchlide) levelse6
- Direction
- increasinge6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e6“MT also regulated chlorophyll metabolism by promoting synthesis [increasing chlorophyll a and b , 5-aminolevulinic acid (ALA), Mg-protoporphyrin (Mg Proto), and protochlorophyllide (Pchlide) levels]”
Claim · model-written summary
Melatonin upregulated the synthesis genes SlHEMA1, SlPORB and SlPORC in tomato seedlings.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MTe6
- Gene
- SlHEMA1 , SlPORB , SlPORCe7
- Outcome
- synthesis genese7
- Direction
- upregulatinge7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e6“MT also regulated chlorophyll metabolism by promoting synthesis [increasing chlorophyll a and b , 5-aminolevulinic acid (ALA), Mg-protoporphyrin (Mg Proto), and protochlorophyllide (Pchlide) levels]”
e7“upregulating synthesis genes ( SlHEMA1 , SlPORB , SlPORC , and SlCHLI ) while inhibiting degradation genes ( SlCLH1 , SlCLH2 , SlPAO , SlPPH , and SlRCCR )”
Claim · model-written summary
Melatonin upregulated the synthesis gene SlCHLI in tomato seedlings.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MTe6
- Gene
- SlCHLIe7
- Outcome
- synthesis genese7
- Direction
- upregulatinge7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e6“MT also regulated chlorophyll metabolism by promoting synthesis [increasing chlorophyll a and b , 5-aminolevulinic acid (ALA), Mg-protoporphyrin (Mg Proto), and protochlorophyllide (Pchlide) levels]”
e7“upregulating synthesis genes ( SlHEMA1 , SlPORB , SlPORC , and SlCHLI ) while inhibiting degradation genes ( SlCLH1 , SlCLH2 , SlPAO , SlPPH , and SlRCCR )”
Claim · model-written summary
Melatonin inhibited the degradation genes SlCLH1, SlCLH2 and SlPAO in tomato seedlings.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MTe6
- Gene
- SlCLH1 , SlCLH2 , SlPAOe7
- Outcome
- degradation genese7
- Direction
- inhibitinge7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e6“MT also regulated chlorophyll metabolism by promoting synthesis [increasing chlorophyll a and b , 5-aminolevulinic acid (ALA), Mg-protoporphyrin (Mg Proto), and protochlorophyllide (Pchlide) levels]”
e7“upregulating synthesis genes ( SlHEMA1 , SlPORB , SlPORC , and SlCHLI ) while inhibiting degradation genes ( SlCLH1 , SlCLH2 , SlPAO , SlPPH , and SlRCCR )”
Claim · model-written summary
Melatonin inhibited the degradation genes SlPPH and SlRCCR in tomato seedlings.
- Taxon
- tomatoSolanum lycopersicumt0
- Treatment
- MTe6
- Gene
- SlPPH , and SlRCCRe7
- Outcome
- degradation genese7
- Direction
- inhibitinge7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“tomato seedlings”
e6“MT also regulated chlorophyll metabolism by promoting synthesis [increasing chlorophyll a and b , 5-aminolevulinic acid (ALA), Mg-protoporphyrin (Mg Proto), and protochlorophyllide (Pchlide) levels]”
e7“upregulating synthesis genes ( SlHEMA1 , SlPORB , SlPORC , and SlCHLI ) while inhibiting degradation genes ( SlCLH1 , SlCLH2 , SlPAO , SlPPH , and SlRCCR )”
The same questions in other papers
melatonin · physiology: oxidative · Solanum lycopersicum (tomato)Results differ
34 papers in the same direction as this paper
- positive
- positive
- positive
31 papers more in this group
See all 35 papers →melatonin · physiology: photosynthesis · Solanum lycopersicum (tomato)Positive and negative results
27 papers in the same direction as this paper · 1 in the opposite direction
- positive
- positive
- positive
25 papers more in this group
See all 29 papers →melatonin · soil: biology · Solanum lycopersicum (tomato)Results agree
3 papers in the same direction as this paper
- positive
- positive
- positive
melatonin · physiology: osmolytes · Solanum lycopersicum (tomato)Results agree
6 papers in the same direction as this paper
- positive
- positive
- positive
3 papers more in this group
See all 7 papers →melatonin · physiology: pigments · Solanum lycopersicum (tomato)Results agree
15 papers in the same direction as this paper
- positive
- positive
- positive
12 papers more in this group
See all 16 papers →melatonin · molecular: expression · Solanum lycopersicum (tomato)Results agree
21 papers in the same direction as this paper
- positive
- positive
- positive
18 papers more in this group
See all 22 papers →melatonin · molecular: metabolites · Solanum lycopersicum (tomato)Results agree
22 papers in the same direction as this paper
- positive
- positive
- positive
19 papers more in this group
See all 23 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.