Abstract
Rice is the third largest food crop in the world, especially in Asia. Its production in various regions is affected to different degrees by drought stress. Melatonin (MT), a novel growth regulator, plays an essential role in enhancing stress resistance in crops. Nevertheless, the underlying mechanism by which melatonin helps mitigate drought damage in rice remains unclear. Therefore, in the present study, rice seedlings pretreated with melatonin (200 μM) were stressed with drought (water potential of −0.5 MPa). These rice seedlings were subsequently examined for their phenotypes and physiological and molecular properties, including metabolite contents, enzyme activities, and the corresponding gene expression levels. The findings demonstrated that drought stress induced an increase in malondialdehyde (MDA) levels, lipoxygenase (LOX) activity, and reactive oxygen species (ROS, e.g., O2− and H2O2) in rice seedlings. However, the melatonin application significantly reduced LOX activity and the MDA and ROS contents (O2− production rate and H2O2 content), with a decrease of 29.35%, 47.23%, and (45.54% and 49.33%), respectively. It activated the expression of ALM1, OsPOX1, OsCATC, and OsAPX2, which increased the activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX), respectively. Meanwhile, the melatonin pretreatment enhanced the proline, fructose, and sucrose content by inducing OsP5CS, OsSUS7, and OsSPS1 gene expression levels. Moreover, the melatonin pretreatment considerably up-regulated the expression levels of the melatonin synthesis genes TDC2 and ASMT1 under drought stress by 7-fold and 5-fold, approximately. These improvements were reflected by an increase in the relative water content (RWC) and the root-shoot ratio in the drought-stressed rice seedlings that received a melatonin application. Consequently, melatonin considerably reduced the adverse effects of drought stress on rice seedlings and improved rice’s ability to tolerate drought by primarily boosting endogenous antioxidant enzymes and osmoregulation abilities.
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 13
Claim · model-written summary
Drought increased MDA levels, LOX activity, and reactive oxygen species.
- Taxon
- rice seedlings
Oryza sativae1 - Treatment
- drought stresse0
- Outcome
- malondialdehyde (MDA) levels, lipoxygenase (LOX) activity, and reactive oxygen species (ROS, e.g., O2− and H2O2)e0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“drought stress induced an increase in malondialdehyde (MDA) levels, lipoxygenase (LOX) activity, and reactive oxygen species (ROS, e.g., O2− and H2O2) in rice seedlings”
e1“rice seedlings pretreated with melatonin (200 μM)”
Claim · model-written summary
Melatonin reduced LOX activity by 29.35%.
- Taxon
- rice seedlingsOryza sativae1
- Treatment
- melatonin applicatione0
- Outcome
- LOX activitye0
- Direction
- reducede0
- Value
- 29.35%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin application significantly reduced LOX activity and the MDA and ROS contents (O2− production rate and H2O2 content), with a decrease of 29.35%, 47.23%, and (45.54% and 49.33%), respectively”
e1“rice seedlings pretreated with melatonin (200 μM)”
Claim · model-written summary
Melatonin reduced MDA content by 47.23%.
- Taxon
- rice seedlingsOryza sativae1
- Treatment
- melatonin applicatione0
- Outcome
- MDAe0
- Direction
- reducede0
- Value
- 47.23%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin application significantly reduced LOX activity and the MDA and ROS contents (O2− production rate and H2O2 content), with a decrease of 29.35%, 47.23%, and (45.54% and 49.33%), respectively”
e1“rice seedlings pretreated with melatonin (200 μM)”
Claim · model-written summary
Melatonin reduced O2− production rate by 45.54%.
- Taxon
- rice seedlingsOryza sativae1
- Treatment
- melatonin applicatione0
- Outcome
- O2− production ratee0
- Direction
- reducede0
- Value
- 45.54%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin application significantly reduced LOX activity and the MDA and ROS contents (O2− production rate and H2O2 content), with a decrease of 29.35%, 47.23%, and (45.54% and 49.33%), respectively”
e1“rice seedlings pretreated with melatonin (200 μM)”
Claim · model-written summary
Melatonin reduced H2O2 content by 49.33%.
- Taxon
- rice seedlingsOryza sativae1
- Treatment
- melatonin applicatione0
- Outcome
- H2O2 contente0
- Direction
- reducede0
- Value
- 49.33%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin application significantly reduced LOX activity and the MDA and ROS contents (O2− production rate and H2O2 content), with a decrease of 29.35%, 47.23%, and (45.54% and 49.33%), respectively”
e1“rice seedlings pretreated with melatonin (200 μM)”
Claim · model-written summary
Melatonin activated ALM1, OsPOX1, OsCATC, and OsAPX2 expression.
- Taxon
- rice seedlingsOryza sativat0
- Treatment
- melatonint0
- Outcome
- expression of ALM1, OsPOX1, OsCATC, and OsAPX2e0
- Direction
- activatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“It activated the expression of ALM1, OsPOX1, OsCATC, and OsAPX2”
t0“Melatonin Enhances Drought Tolerance in Rice Seedlings”
Claim · model-written summary
Melatonin increased SOD, POD, CAT, and APX activity.
- Taxon
- rice seedlingsOryza sativat0
- Treatment
- melatonint0
- Outcome
- activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX)e0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased the activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX)”
t0“Melatonin Enhances Drought Tolerance in Rice Seedlings”
Claim · model-written summary
Melatonin increased proline, fructose, and sucrose content.
- Taxon
- rice seedlingsOryza sativae1
- Treatment
- melatonin pretreatmente0
- Outcome
- proline, fructose, and sucrose contente0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin pretreatment enhanced the proline, fructose, and sucrose content by inducing OsP5CS, OsSUS7, and OsSPS1 gene expression levels”
e1“rice seedlings pretreated with melatonin (200 μM)”
Claim · model-written summary
Melatonin induced OsP5CS, OsSUS7, and OsSPS1 expression.
- Taxon
- rice seedlingsOryza sativae1
- Treatment
- melatonin pretreatmente0
- Outcome
- OsP5CS, OsSUS7, and OsSPS1 gene expression levelse0
- Direction
- inducinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin pretreatment enhanced the proline, fructose, and sucrose content by inducing OsP5CS, OsSUS7, and OsSPS1 gene expression levels”
e1“rice seedlings pretreated with melatonin (200 μM)”
Claim · model-written summary
Melatonin upregulated TDC2 expression approximately sevenfold under drought.
- Taxon
- rice seedlingsOryza sativae1
- Treatment
- melatonin pretreatmente0
- Outcome
- expression levels of the melatonin synthesis genes TDC2e0
- Direction
- up-regulatede0
- Value
- 7-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin pretreatment considerably up-regulated the expression levels of the melatonin synthesis genes TDC2 and ASMT1 under drought stress by 7-fold and 5-fold, approximately”
e1“rice seedlings pretreated with melatonin (200 μM)”
Claim · model-written summary
Melatonin upregulated ASMT1 expression approximately fivefold under drought.
- Taxon
- rice seedlingsOryza sativae1
- Treatment
- melatonin pretreatmente0
- Outcome
- ASMT1e0
- Direction
- up-regulatede0
- Value
- 5-folde0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin pretreatment considerably up-regulated the expression levels of the melatonin synthesis genes TDC2 and ASMT1 under drought stress by 7-fold and 5-fold, approximately”
e1“rice seedlings pretreated with melatonin (200 μM)”
Claim · model-written summary
Melatonin increased relative water content under drought.
- Taxon
- rice seedlingsOryza sativae1
- Treatment
- melatonin applicatione0
- Outcome
- relative water content (RWC)e0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increase in the relative water content (RWC) and the root-shoot ratio in the drought-stressed rice seedlings that received a melatonin application”
e1“rice seedlings pretreated with melatonin (200 μM)”
Claim · model-written summary
Melatonin increased root-shoot ratio under drought.
- Taxon
- rice seedlingsOryza sativae1
- Treatment
- melatonin applicatione0
- Outcome
- root-shoot ratioe0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increase in the relative water content (RWC) and the root-shoot ratio in the drought-stressed rice seedlings that received a melatonin application”
e1“rice seedlings pretreated with melatonin (200 μM)”
The same questions in other papers
melatonin · physiology: osmolytes · Oryza sativa (rice)Results agree
5 papers in the same direction as this paper
- positive
- positive
- positive
2 papers more in this group
See all 6 papers →melatonin · physiology: water · Oryza sativa (rice)Results agree
5 papers in the same direction as this paper
- positive
- positive
- positive
2 papers more in this group
See all 6 papers →melatonin · physiology: antioxidant enzymes · Oryza sativa (rice)Results agree
12 papers in the same direction as this paper
- positive
- positive
- positive
9 papers more in this group
See all 13 papers →melatonin · molecular: expression · Oryza sativa (rice)Results agree
19 papers in the same direction as this paper
- positive
- positive
- positive
16 papers more in this group
See all 20 papers →melatonin · physiology: oxidative · Oryza sativa (rice)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 · growth · Oryza sativa (rice)Results agree
27 papers in the same direction as this paper
- positive
- positive
- positive
24 papers more in this group
See all 28 papers →drought · physiology: oxidative · Oryza sativa (rice)Results differ
44 papers in the same direction as this paper · 10 in the opposite direction
- negative
- positive
- positive
51 papers more in this group
See all 55 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.