Abstract
Melatonin is effective in modulating metabolism and regulating growth and development in many plants under biotic and abiotic stress. However, there is no systematic quantification of melatonin effects on maize growth, gas exchange, chlorophyll content, and the antioxidant defense system. A meta-analysis was conducted on thirty-two currently available published articles to evaluate the effect of stress types, study types, and maize varieties on response ratio (lnRR++) of “melatonin” to “control (no melatonin)” on plant growth, enzyme activities, gas exchange parameters, and photosynthetic pigments. Our findings revealed that melatonin application overall increased plant height, leaf area, root length, fresh and dry root weight and shoot weight, superoxide dismutase (SOD), peroxide (POD), catalase (CAT), ascorbate peroxidase (APX), soluble sugar and protein, photosynthetic rate, stomatal conductance, transpiration rate, chlorophyll, and carotenoid in maize leaf under stress conditions. In contrast, melatonin application decreased the levels of hydrogen peroxide (H2O2), superoxide anion (O2−), malondialdehyde (MDA), and electrolyte leakage. The categorical meta-analysis demonstrated that melatonin application to chilling stress resulted in higher SOD activity followed by salt stress. Melatonin application to all stress types resulted in higher POD, CAT and APX activities, except Cd stress, which had no effect on POD and decreased CAT by 38% compared to control. Compared to control, melatonin resulted in lower reactive oxygen species (ROS) and electrolyte leakage under no stress, Cd, drought, salt, lead, heat, and chilling stress in all study types (pot, growth chamber, hydroponic, and field), except O2 content which was not affected in pot and growth chamber studies. It was concluded that melatonin alleviates oxidative damage by improving stress tolerance, regulating the antioxidant defense system, and increasing leaf chlorophyll content compared to control.
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 application increased plant height, leaf area and root length of maize under stress conditions.
- Treatment
- melatonin applicatione1
- Outcome
- plant height, leaf area, root lengthe1
- Direction
- increasede1
- Qualifier
- under stress conditionse3
- Comparator
- controle2
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“melatonin application overall increased plant height, leaf area, root length”
e2“Compared to control, melatonin resulted in lower reactive oxygen species (ROS)”
e3“in maize leaf under stress conditions”
Claim · model-written summary
Melatonin application increased fresh and dry root weight and shoot weight of maize under stress conditions.
- Treatment
- melatonin applicatione1
- Outcome
- fresh and dry root weight and shoot weighte1
- Direction
- increasede1
- Qualifier
- under stress conditionse3
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“melatonin application overall increased plant height, leaf area, root length, fresh and dry root weight and shoot weight”
e2“Compared to control, melatonin resulted in lower reactive oxygen species (ROS)”
e3“in maize leaf under stress conditions”
Claim · model-written summary
Melatonin application increased SOD, POD and CAT in maize under stress conditions.
- Treatment
- melatonin applicatione1
- Outcome
- superoxide dismutase (SOD), peroxide (POD), catalase (CAT)e1
- Direction
- increasede1
- Qualifier
- under stress conditionse3
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“melatonin application overall increased plant height, leaf area, root length, fresh and dry root weight and shoot weight, superoxide dismutase (SOD), peroxide (POD), catalase (CAT)”
e2“Compared to control, melatonin resulted in lower reactive oxygen species (ROS)”
e3“in maize leaf under stress conditions”
Claim · model-written summary
Melatonin application increased APX activity and soluble sugar and protein in maize under stress conditions.
- Treatment
- melatonin applicatione1
- Outcome
- ascorbate peroxidase (APX), soluble sugar and proteine1
- Direction
- increasede1
- Qualifier
- under stress conditionse3
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“melatonin application overall increased plant height, leaf area, root length, fresh and dry root weight and shoot weight, superoxide dismutase (SOD), peroxide (POD), catalase (CAT), ascorbate peroxidase (APX), soluble sugar and protein”
e2“Compared to control, melatonin resulted in lower reactive oxygen species (ROS)”
e3“in maize leaf under stress conditions”
Claim · model-written summary
Melatonin application increased photosynthetic rate, stomatal conductance and transpiration rate of maize under stress conditions.
- Treatment
- melatonin applicatione1
- Outcome
- photosynthetic rate, stomatal conductance, transpiration ratee1
- Direction
- increasede1
- Qualifier
- under stress conditionse3
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“melatonin application overall increased plant height, leaf area, root length, fresh and dry root weight and shoot weight, superoxide dismutase (SOD), peroxide (POD), catalase (CAT), ascorbate peroxidase (APX), soluble sugar and protein, photosynthetic rate, stomatal conductance, transpiration rate”
e2“Compared to control, melatonin resulted in lower reactive oxygen species (ROS)”
e3“in maize leaf under stress conditions”
Claim · model-written summary
Melatonin application increased chlorophyll and carotenoid in maize leaves under stress conditions.
- Treatment
- melatonin applicatione1
- Outcome
- chlorophyll, and carotenoide1
- Direction
- increasede1
- Qualifier
- under stress conditionse3
- Comparator
- controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“melatonin application overall increased plant height, leaf area, root length, fresh and dry root weight and shoot weight, superoxide dismutase (SOD), peroxide (POD), catalase (CAT), ascorbate peroxidase (APX), soluble sugar and protein, photosynthetic rate, stomatal conductance, transpiration rate, chlorophyll, and carotenoid in maize leaf under stress conditions”
e2“Compared to control, melatonin resulted in lower reactive oxygen species (ROS)”
e3“in maize leaf under stress conditions”
Claim · model-written summary
Melatonin application decreased hydrogen peroxide, superoxide anion and malondialdehyde levels in maize.
- Treatment
- melatonin applicatione1
- Outcome
- hydrogen peroxide (H2O2), superoxide anion (O2−), malondialdehyde (MDA)e1
- Direction
- decreasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“In contrast, melatonin application decreased the levels of hydrogen peroxide (H2O2), superoxide anion (O2−), malondialdehyde (MDA)”
Claim · model-written summary
Melatonin application decreased electrolyte leakage in maize.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“In contrast, melatonin application decreased the levels of hydrogen peroxide (H2O2), superoxide anion (O2−), malondialdehyde (MDA), and electrolyte leakage”
Claim · model-written summary
Melatonin applied to chilling stress increased SOD activity in maize more than salt stress did.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“melatonin application to chilling stress resulted in higher SOD activity followed by salt stress”
Claim · model-written summary
Melatonin applied to all stress types increased POD, CAT and APX activities in maize, except under Cd stress.
- Treatment
- Melatonin application to all stress typese1
- Outcome
- POD, CAT and APX activitiese1
- Direction
- highere1
- Qualifier
- except Cd stresse1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“Melatonin application to all stress types resulted in higher POD, CAT and APX activities, except Cd stress”
Claim · model-written summary
Under Cd stress, melatonin had no effect on POD activity in maize.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“except Cd stress, which had no effect on POD”
Claim · model-written summary
Under Cd stress, melatonin decreased CAT activity by 38% compared to control in maize.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“Cd stress, which had no effect on POD and decreased CAT by 38% compared to control”
Claim · model-written summary
Melatonin lowered reactive oxygen species and electrolyte leakage in maize under no stress and under six stress types, in all study types.
- Treatment
- melatonine1
- Outcome
- reactive oxygen species (ROS) and electrolyte leakagee1
- Direction
- lowere1
- Qualifier
- under no stress, Cd, drought, salt, lead, heat, and chilling stresse1
- Comparator
- controle1
- Setting
- pot, growth chamber, hydroponic, and fielde1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“Compared to control, melatonin resulted in lower reactive oxygen species (ROS) and electrolyte leakage under no stress, Cd, drought, salt, lead, heat, and chilling stress in all study types (pot, growth chamber, hydroponic, and field), except O2 content which was not affected in pot and growth chamber studies”
Claim · model-written summary
Melatonin did not affect O2 content of maize in pot and growth chamber studies.
- Treatment
- melatonine1
- Outcome
- O2 contente1
- Direction
- not affectede1
- Comparator
- controle1
- Setting
- pot and growth chamber studiese1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“Compared to control, melatonin resulted in lower reactive oxygen species (ROS) and electrolyte leakage under no stress, Cd, drought, salt, lead, heat, and chilling stress in all study types (pot, growth chamber, hydroponic, and field), except O2 content which was not affected in pot and growth chamber studies”
Claim · model-written summary
Melatonin is concluded to alleviate oxidative damage in maize by improving stress tolerance and regulating the antioxidant defense system.
- Treatment
- melatonine1
- Outcome
- oxidative damagee1
- Qualifier
- by improving stress tolerance, regulating the antioxidant defense systeme1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin effects on maize growth”
e1“It was concluded that melatonin alleviates oxidative damage by improving stress tolerance, regulating the antioxidant defense system, and increasing leaf chlorophyll content compared to control”
The same questions in other papers
cadmium atom · physiology: antioxidant enzymes · Zea mays (maize)Results differ
11 papers in the same direction as this paper · 3 in the opposite direction
- positive
- positive
- positive
11 papers more in this group
See all 15 papers →melatonin · growth · Zea mays (maize)Results differ
27 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- positive
25 papers more in this group
See all 29 papers →cadmium atom · molecular: metabolites · Zea mays (maize)Results differ
35 papers in the same direction as this paper · 12 in the opposite direction
- positive
- positive
- positive
44 papers more in this group
See all 48 papers →melatonin · molecular: metabolites · Zea mays (maize)Positive and negative results
1 paper in the same direction as this paper · 13 in the opposite direction
- positive
- positive
- positive
11 papers more in this group
See all 15 papers →melatonin · physiology: photosynthesis · Zea mays (maize)Positive and negative results
22 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- positive
20 papers more in this group
See all 24 papers →melatonin · physiology: pigments · Zea mays (maize)Results agree
11 papers in the same direction as this paper
- positive
- positive
- positive
8 papers more in this group
See all 12 papers →melatonin · physiology: antioxidant enzymes · Zea mays (maize)Results agree
20 papers in the same direction as this paper
- positive
- positive
- positive
17 papers more in this group
See all 21 papers →melatonin · physiology: oxidative · Zea mays (maize)Results agree
27 papers in the same direction as this paper
- positive
- positive
- positive
24 papers more in this group
See all 28 papers →8 of 11 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.