Abstract
In China, excessive use of nitrogen fertilizers in glasshouses leads to nitrate accumulations in soil and plants, which then limits productivity. Melatonin, an evolutionarily highly conserved molecule, has a wide range of functions in plants. We analyzed the effects of melatonin pretreatment on the growth, mineral nutrition, and nitrogen metabolism in cucumber (Cucumis sativus L. "Jin You No. 1") when seedlings were exposed to nitrate stress. An application of 0.1 mmol/L melatonin significantly improved the growth of plants and reduced their susceptibility to damage due to high nitrate levels (0.6 mol/L) during the ensuing period of stress treatment. Although excess nitrate led to an increase in the concentrations of nitrogen, potassium, and calcium, as well as a decrease in levels of phosphorus and magnesium, exogenous melatonin generally had the opposite effect except for a further rise in calcium concentrations. Pretreatment also significantly reduced the accumulations of nitrate nitrogen and ammonium nitrogen and enhanced the activities of enzymes involved in nitrogen metabolism. Expression of Cs-NR and Cs-GOGAT, two genes that function in that metabolism, was greatly down-regulated when plants were exposed to 0.6 mol/L nitrate, but was up-regulated in plants that had received the 0.1 mmol/L melatonin pretreatment. Our results are the first evidence that melatonin has an important role in modulating the composition of mineral elements and nitrogen metabolism, thereby alleviating the inhibitory effect on growth normally associated with nitrate stress.
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Claims 12
Claim · model-written summary
Melatonin improved cucumber growth under high nitrate.
- Taxon
- cucumber
Cucumis sativust0 - Treatment
- 0.1 mmol/L melatonine0
- Outcome
- growth of plantse0
- Direction
- improvede0
- Qualifier
- high nitrate levels (0.6 mol/L)e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“An application of 0.1 mmol/L melatonin significantly improved the growth of plants and reduced their susceptibility to damage due to high nitrate levels (0.6 mol/L) during the ensuing period of stress treatment.”
t0“cucumber”
Claim · model-written summary
Melatonin reduced cucumber susceptibility to nitrate damage.
- Taxon
- cucumberCucumis sativust0
- Treatment
- 0.1 mmol/L melatonine0
- Outcome
- susceptibility to damage due to high nitrate levelse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“An application of 0.1 mmol/L melatonin significantly improved the growth of plants and reduced their susceptibility to damage due to high nitrate levels (0.6 mol/L) during the ensuing period of stress treatment.”
t0“cucumber”
Claim · model-written summary
Excess nitrate raised nitrogen, potassium and calcium concentrations.
- Taxon
- cucumberCucumis sativust0
- Treatment
- excess nitratee0
- Outcome
- concentrations of nitrogen, potassium, and calciume0
- Direction
- increasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although excess nitrate led to an increase in the concentrations of nitrogen, potassium, and calcium, as well as a decrease in levels of phosphorus and magnesium, exogenous melatonin generally had the opposite effect except for a further rise in calcium concentrations.”
t0“cucumber”
Claim · model-written summary
Excess nitrate lowered phosphorus and magnesium levels.
- Taxon
- cucumberCucumis sativust0
- Treatment
- excess nitratee0
- Outcome
- levels of phosphorus and magnesiume0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although excess nitrate led to an increase in the concentrations of nitrogen, potassium, and calcium, as well as a decrease in levels of phosphorus and magnesium, exogenous melatonin generally had the opposite effect except for a further rise in calcium concentrations.”
t0“cucumber”
Claim · model-written summary
Melatonin generally countered the nitrate driven mineral concentration changes other than calcium.
- Taxon
- cucumberCucumis sativust0
- Treatment
- exogenous melatonine0
- Outcome
- concentrations of nitrogen, potassium, and calcium, as well as a decrease in levels of phosphorus and magnesiume0
- Qualifier
- opposite effect except for a further rise in calcium concentrationse0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although excess nitrate led to an increase in the concentrations of nitrogen, potassium, and calcium, as well as a decrease in levels of phosphorus and magnesium, exogenous melatonin generally had the opposite effect except for a further rise in calcium concentrations.”
t0“cucumber”
Claim · model-written summary
Melatonin further raised calcium concentrations.
- Taxon
- cucumberCucumis sativust0
- Treatment
- exogenous melatonine0
- Outcome
- calcium concentrationse0
- Direction
- further risee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Although excess nitrate led to an increase in the concentrations of nitrogen, potassium, and calcium, as well as a decrease in levels of phosphorus and magnesium, exogenous melatonin generally had the opposite effect except for a further rise in calcium concentrations.”
t0“cucumber”
Claim · model-written summary
Melatonin pretreatment reduced nitrate and ammonium nitrogen accumulation.
- Taxon
- cucumberCucumis sativust0
- Treatment
- Pretreatmente0
- Outcome
- accumulations of nitrate nitrogen and ammonium nitrogene0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pretreatment also significantly reduced the accumulations of nitrate nitrogen and ammonium nitrogen and enhanced the activities of enzymes involved in nitrogen metabolism.”
t0“cucumber”
Claim · model-written summary
Melatonin pretreatment enhanced nitrogen metabolism enzyme activities.
- Taxon
- cucumberCucumis sativust0
- Treatment
- Pretreatmente0
- Outcome
- activities of enzymes involved in nitrogen metabolisme0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Pretreatment also significantly reduced the accumulations of nitrate nitrogen and ammonium nitrogen and enhanced the activities of enzymes involved in nitrogen metabolism.”
t0“cucumber”
Claim · model-written summary
Cs-NR expression was downregulated by nitrate.
- Taxon
- cucumberCucumis sativust0
- Treatment
- 0.6 mol/L nitratee0
- Gene
- Cs-NRe0
- Outcome
- Expression of Cs-NRe0
- Direction
- down-regulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of Cs-NR and Cs-GOGAT, two genes that function in that metabolism, was greatly down-regulated when plants were exposed to 0.6 mol/L nitrate, but was up-regulated in plants that had received the 0.1 mmol/L melatonin pretreatment.”
t0“cucumber”
Claim · model-written summary
Cs-NR expression was upregulated after melatonin pretreatment.
- Taxon
- cucumberCucumis sativust0
- Treatment
- 0.1 mmol/L melatonin pretreatmente0
- Gene
- Cs-NRe0
- Outcome
- Expression of Cs-NRe0
- Direction
- up-regulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of Cs-NR and Cs-GOGAT, two genes that function in that metabolism, was greatly down-regulated when plants were exposed to 0.6 mol/L nitrate, but was up-regulated in plants that had received the 0.1 mmol/L melatonin pretreatment.”
t0“cucumber”
Claim · model-written summary
Cs-GOGAT expression was downregulated by nitrate.
- Taxon
- cucumberCucumis sativust0
- Treatment
- 0.6 mol/L nitratee0
- Gene
- Cs-GOGATe0
- Outcome
- Expression of Cs-NR and Cs-GOGATe0
- Direction
- down-regulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of Cs-NR and Cs-GOGAT, two genes that function in that metabolism, was greatly down-regulated when plants were exposed to 0.6 mol/L nitrate, but was up-regulated in plants that had received the 0.1 mmol/L melatonin pretreatment.”
t0“cucumber”
Claim · model-written summary
Cs-GOGAT expression was upregulated after melatonin pretreatment.
- Taxon
- cucumberCucumis sativust0
- Treatment
- 0.1 mmol/L melatonin pretreatmente0
- Gene
- Cs-GOGATe0
- Outcome
- Expression of Cs-NR and Cs-GOGATe0
- Direction
- up-regulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Expression of Cs-NR and Cs-GOGAT, two genes that function in that metabolism, was greatly down-regulated when plants were exposed to 0.6 mol/L nitrate, but was up-regulated in plants that had received the 0.1 mmol/L melatonin pretreatment.”
t0“cucumber”
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