Abstract
Drought stress is a major abiotic factor that limits cotton yield stability and severely impairs cotton growth, development, and fiber quality. Exogenous melatonin has significant potential in enhancing crop stress resistance, but its effects and mechanisms when applied to the roots in cotton's response to drought remain unclear. To clarify the regulatory role of melatonin in cotton's drought tolerance, a series of pot and field experiments were conducted using the 'Lumian 532′ variety as the material. Seedlings were subjected to either sufficient watering (soil relative water content 70–75 %) or drought stress (soil relative water content 40–45 %) conditions, with simultaneous treatments of root application of melatonin (50 μM, which was determined as the optimal concentration from preliminary screening of 10–300 μM) and no application of melatonin. A randomized design was adopted for the experiment, with each treatment replicated 3 times. Results showed that root-applied melatonin effectively mitigates the growth inhibitory effects of drought stress on plant growth. Specifically, an optimal concentration of 50 μM melatonin significantly increased plant height, root length, and root surface area by 36.79 %, 35.36 %, and 51.42 %, respectively, compared to untreated drought-stressed plants. Melatonin treatment significantly enhanced the net photosynthetic rate, stomatal conductance, and maximum photochemical efficiency of PSII during drought stress. Additionally, it enhanced the activity of antioxidant enzymes, including superoxide dismutase, peroxidase, and catalase, while promoting the accumulation of ascorbic acid and glutathione. Melatonin significantly reduced H 2 O 2 and O 2 − levels by 19.64–20.23 % and 43.83–68.78 %, respectively. Furthermore, melatonin application significantly increased the levels of gibberellin, indoleacetic acid, and endogenous melatonin in roots, while the content of abscisic acid was significantly reduced by 24.93 % (P < 0.05), thereby alleviating drought-induced hormonal imbalance and enhancing drought. resistance. Field trials revealed that root-applied melatonin significantly increased seed cotton yield by 20.10 % compared to drought treatment, primarily through elevated boll numbers per unit area. These research results indicate that the application of low-dose melatonin to the roots effectively enhances the drought resistance of cotton by synergistically improving photosynthesis, antioxidant capacity, and hormone balance. This provides a theoretical basis and practical reference for incorporating melatonin into agronomic management strategies to stabilize cotton yields under water-limited conditions. • Root-applied melatonin significantly mitigates the inhibitory effects of drought stress on cotton growth and yield. • An optimal concentration of 50 μM melatonin is identified to maximize drought resistance in cotton. • Melatonin boosts cotton drought tolerance via "photosynthetic enhancement-antioxidant synergy-hormone balance" cascade.
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Claims 13
Claim · model-written summary
The optimal melatonin concentration identified by screening was 50 μM.
- Taxon
- cotton
Gossypium hirsutumt0 - Outcome
- optimal concentratione0
- Value
- 50 μMe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“50 μM, which was determined as the optimal concentration from preliminary screening of 10–300 μM”
t0“cotton”
Claim · model-written summary
Root melatonin increased plant height by 36.79% against untreated drought-stressed plants.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- 50 μM melatonine0
- Outcome
- plant heighte0
- Direction
- increasede0
- Value
- 36.79 %e0
- Comparator
- untreated drought-stressed plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an optimal concentration of 50 μM melatonin significantly increased plant height, root length, and root surface area by 36.79 %, 35.36 %, and 51.42 %, respectively, compared to untreated drought-stressed plants”
t0“cotton”
Claim · model-written summary
Root melatonin increased root length by 35.36% against untreated drought-stressed plants.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- 50 μM melatonine0
- Outcome
- root lengthe0
- Direction
- increasede0
- Value
- 35.36 %e0
- Comparator
- untreated drought-stressed plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an optimal concentration of 50 μM melatonin significantly increased plant height, root length, and root surface area by 36.79 %, 35.36 %, and 51.42 %, respectively, compared to untreated drought-stressed plants”
t0“cotton”
Claim · model-written summary
Root melatonin increased root surface area by 51.42% against untreated drought-stressed plants.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- 50 μM melatonine0
- Outcome
- root surface areae0
- Direction
- increasede0
- Value
- 51.42 %e0
- Comparator
- untreated drought-stressed plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an optimal concentration of 50 μM melatonin significantly increased plant height, root length, and root surface area by 36.79 %, 35.36 %, and 51.42 %, respectively, compared to untreated drought-stressed plants”
t0“cotton”
Claim · model-written summary
Melatonin enhanced net photosynthetic rate, stomatal conductance and PSII efficiency during drought.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- Melatonin treatmente0
- Outcome
- net photosynthetic rate, stomatal conductance, and maximum photochemical efficiency of PSIIe0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Melatonin treatment significantly enhanced the net photosynthetic rate, stomatal conductance, and maximum photochemical efficiency of PSII during drought stress”
t0“cotton”
Claim · model-written summary
Melatonin enhanced activity of superoxide dismutase, peroxidase and catalase.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- melatonint1
- Outcome
- activity of antioxidant enzymese0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“it enhanced the activity of antioxidant enzymes, including superoxide dismutase, peroxidase, and catalase”
t0“cotton”
t1“melatonin”
Claim · model-written summary
Melatonin promoted accumulation of ascorbic acid and glutathione.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- melatonint1
- Outcome
- accumulation of ascorbic acid and glutathionee0
- Direction
- promotinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“while promoting the accumulation of ascorbic acid and glutathione”
t0“cotton”
t1“melatonin”
Claim · model-written summary
Melatonin reduced H 2 O 2 levels by 19.64–20.23%.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- Melatonine0
- Outcome
- H 2 O 2e0
- Direction
- reducede0
- Value
- 19.64–20.23 %e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Melatonin significantly reduced H 2 O 2 and O 2 − levels by 19.64–20.23 % and 43.83–68.78 %, respectively”
t0“cotton”
Claim · model-written summary
Melatonin reduced O 2 − levels by 43.83–68.78%.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- Melatonine0
- Outcome
- O 2 −e0
- Direction
- reducede0
- Value
- 43.83–68.78 %e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Melatonin significantly reduced H 2 O 2 and O 2 − levels by 19.64–20.23 % and 43.83–68.78 %, respectively”
t0“cotton”
Claim · model-written summary
Melatonin increased root levels of gibberellin, indoleacetic acid and endogenous melatonin.
- Taxon
- cottonGossypium hirsutumt0
- Organ / stage
- rootse0
- Treatment
- melatonin applicatione0
- Outcome
- levels of gibberellin, indoleacetic acid, and endogenous melatonine0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin application significantly increased the levels of gibberellin, indoleacetic acid, and endogenous melatonin in roots”
t0“cotton”
Claim · model-written summary
Melatonin reduced abscisic acid content by 24.93%.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- melatonint1
- Outcome
- content of abscisic acide0
- Direction
- reducede0
- Value
- 24.93 %e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the content of abscisic acid was significantly reduced by 24.93 % (P < 0.05)”
t0“cotton”
t1“melatonin”
Claim · model-written summary
Root melatonin increased field seed cotton yield by 20.10% against drought treatment.
- Taxon
- cottonGossypium hirsutume0
- Treatment
- root-applied melatonine0
- Outcome
- seed cotton yielde0
- Direction
- increasede0
- Value
- 20.10 %e0
- Comparator
- drought treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“root-applied melatonin significantly increased seed cotton yield by 20.10 % compared to drought treatment”
t0“cotton”
Claim · model-written summary
Melatonin increased boll numbers per unit area.
- Taxon
- cottonGossypium hirsutumt0
- Treatment
- melatonint1
- Outcome
- boll numbers per unit areae0
- Direction
- elevatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“primarily through elevated boll numbers per unit area”
t0“cotton”
t1“melatonin”
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See all 16 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.