Abstract
Melatonin regulates growth in many plants; however, the mechanism remains unclear. In this study, exogenous melatonin feeding resulted in both promotional (≤10 μm) and inhibitory (≥100 μm) effects on maize seedling growth. Initial analyses suggested positive correlations between the amount of melatonin and sucrose synthesis and hydrolysis-related gene expression, enzyme activities, and sucrose metabolites. However, assays of photosynthetic rate, hexokinase (HxK) activity, expression of photosynthetic marker genes, and HxK-related genes showed opposite effects under 10 μm (positive) and 100 μm (negative) melatonin treatments. Similarly, 10 μm melatonin accelerated starch catabolism at night, whereas 100 μm melatonin significantly decreased this process and led to starch accumulation in photosynthetic tissues. Furthermore, expression analysis of genes related to sucrose phloem loading resulted in a slight upregulation of sucrose transporters (SUT1 and SUT2) when seedlings were induced with 10 μm melatonin, while treatment with 100 μm melatonin resulted in significant downregulation of these sucrose transporter genes (SUT1 and SUT2), as well as tie-dyed2 (Tdy2) and sucrose export defective 1. Taken together, these results suggest that low doses of melatonin benefit maize seedling growth by promoting sugar metabolism, photosynthesis, and sucrose phloem loading. Conversely, high doses of melatonin inhibit seedling growth by inducing the excessive accumulation of sucrose, hexose and starch, suppressing photosynthesis and sucrose phloem loading.
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Claims 15
Claim · model-written summary
Melatonin at no more than 10 μm promoted maize seedling growth.
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exogenous melatonin feeding resulted in both promotional (≤10 μm) and inhibitory (≥100 μm) effects on maize seedling growth”
Claim · model-written summary
Melatonin at at least 100 μm inhibited maize seedling growth.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exogenous melatonin feeding resulted in both promotional (≤10 μm) and inhibitory (≥100 μm) effects on maize seedling growth”
Claim · model-written summary
Melatonin amount positively correlated with sucrose gene expression, enzyme activities and metabolites.
- Compound
- melatonine0
- Outcome
- sucrose synthesis and hydrolysis-related gene expression, enzyme activities, and sucrose metabolitese0
- Direction
- positive correlationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“positive correlations between the amount of melatonin and sucrose synthesis and hydrolysis-related gene expression, enzyme activities, and sucrose metabolites”
t0“maize”
Claim · model-written summary
At 10 μm melatonin positively affected photosynthetic rate and HxK activity.
- Treatment
- 10 μm (positive)e0
- Outcome
- photosynthetic rate, hexokinase (HxK) activitye0
- Direction
- positivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“assays of photosynthetic rate, hexokinase (HxK) activity, expression of photosynthetic marker genes, and HxK-related genes showed opposite effects under 10 μm (positive) and 100 μm (negative) melatonin treatments”
t0“maize”
Claim · model-written summary
At 100 μm melatonin negatively affected photosynthetic rate and HxK activity.
- Treatment
- 100 μm (negative) melatonin treatmentse0
- Outcome
- photosynthetic rate, hexokinase (HxK) activitye0
- Direction
- negativee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“assays of photosynthetic rate, hexokinase (HxK) activity, expression of photosynthetic marker genes, and HxK-related genes showed opposite effects under 10 μm (positive) and 100 μm (negative) melatonin treatments”
t0“maize”
Claim · model-written summary
At 10 μm melatonin positively affected photosynthetic marker and HxK-related gene expression.
- Treatment
- 10 μm (positive)e0
- Outcome
- expression of photosynthetic marker genes, and HxK-related genese0
- Direction
- positivee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“expression of photosynthetic marker genes, and HxK-related genes showed opposite effects under 10 μm (positive) and 100 μm (negative) melatonin treatments”
t0“maize”
Claim · model-written summary
At 100 μm melatonin negatively affected photosynthetic marker and HxK-related gene expression.
- Treatment
- 100 μm (negative) melatonin treatmentse0
- Outcome
- expression of photosynthetic marker genes, and HxK-related genese0
- Direction
- negativee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“expression of photosynthetic marker genes, and HxK-related genes showed opposite effects under 10 μm (positive) and 100 μm (negative) melatonin treatments”
t0“maize”
Claim · model-written summary
At 10 μm melatonin accelerated nocturnal starch catabolism.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“10 μm melatonin accelerated starch catabolism at night”
t0“maize”
Claim · model-written summary
At 100 μm melatonin significantly decreased nocturnal starch catabolism.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“100 μm melatonin significantly decreased this process and led to starch accumulation in photosynthetic tissues”
t0“maize”
Claim · model-written summary
At 100 μm melatonin caused starch accumulation in photosynthetic tissues.
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“100 μm melatonin significantly decreased this process and led to starch accumulation in photosynthetic tissues”
t0“maize”
Claim · model-written summary
At 10 μm melatonin slightly upregulated SUT1 and SUT2.
- Treatment
- 10 μm melatonine0
- Gene
- SUT1 and SUT2e0
- Outcome
- upregulation of sucrose transporterse0
- Direction
- upregulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“slight upregulation of sucrose transporters (SUT1 and SUT2) when seedlings were induced with 10 μm melatonin”
t0“maize”
Claim · model-written summary
At 100 μm melatonin significantly downregulated SUT1 and SUT2.
- Treatment
- 100 μm melatonine0
- Gene
- SUT1 and SUT2e0
- Outcome
- downregulation of these sucrose transporter genese0
- Direction
- downregulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“100 μm melatonin resulted in significant downregulation of these sucrose transporter genes (SUT1 and SUT2)”
t0“maize”
Claim · model-written summary
At 100 μm melatonin also downregulated Tdy2 and sucrose export defective 1.
- Treatment
- 100 μm melatonine0
- Gene
- tie-dyed2 (Tdy2) and sucrose export defective 1e0
- Outcome
- downregulatione0
- Direction
- downregulatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“100 μm melatonin resulted in significant downregulation of these sucrose transporter genes (SUT1 and SUT2), as well as tie-dyed2 (Tdy2) and sucrose export defective 1”
t0“maize”
Claim · model-written summary
Authors infer low melatonin promotes growth through sugar metabolism, photosynthesis and sucrose loading.
- Treatment
- low doses of melatonine0
- Outcome
- seedling growthe0
- Qualifier
- promoting sugar metabolism, photosynthesis, and sucrose phloem loadinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“low doses of melatonin benefit maize seedling growth by promoting sugar metabolism, photosynthesis, and sucrose phloem loading”
Claim · model-written summary
Authors infer high melatonin inhibits growth through sugar accumulation and suppressed photosynthesis and sucrose loading.
- Treatment
- high doses of melatonine0
- Outcome
- seedling growthe0
- Qualifier
- excessive accumulation of sucrose, hexose and starch, suppressing photosynthesis and sucrose phloem loadinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“high doses of melatonin inhibit seedling growth by inducing the excessive accumulation of sucrose, hexose and starch, suppressing photosynthesis and sucrose phloem loading”
t0“maize”
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