Abstract
As a type of abiotic stress, drought limits plant growth and productivity. The increased demand for the valuable essential oil extracted from geranium (Pelargonium graveolens L.) is mainly regulated by plant growth, which is adversely affected by drought. Melatonin (MT) has been used to enhance plant growth under various abiotic stresses, although its impact on overcoming drought stress in aromatic plants, including geranium, has not yet been investigated. In the current investigation, MT at 100 µM was applied at 100% (well-watered) or 50% (drought stress) field capacity to verify the role of MT in geranium under drought stress. Drought stress markedly reduced growth parameters, herb yield, and total chlorophyll content; however, MT alleviated these effects. The herb yield of the stressed plants was reduced by 59.91% compared to the unstressed plants, while this reduction was only 14.38% when MT was applied. In contrast, drought enhanced the essential oil percentage in geranium leaves. Despite the reduction in oil yield caused by drought, MT application mitigated this reduction and improved both oil yield and oil components. Moreover, the MT treatment enhanced the accumulation of total phenols, glutathione, and proline and improved the activity of ascorbate peroxidase, catalase, and glutathione reductase, resulting in the alleviation of drought-induced oxidative damage. Consequently, MT reduced both hydrogen peroxide and malondialdehyde accumulation by 71.11 and 48.30%, respectively, under drought, thereby maintaining the cellular structures’ integrity. Overall, this is the first report that reveals the ability of MT application to improve geranium oil yield and resistance to drought by enhancing the antioxidant defense system. The results enrich awareness regarding the potential benefits of the external application of MT and its roles that can help researchers to improve aromatic plants’ performance and productivity under drought stress.
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Claims 14
Claim · model-written summary
Drought reduced geranium growth parameters, herb yield and total chlorophyll content.
- Treatment
- Drought stresse0
- Outcome
- growth parameters, herb yield, and total chlorophyll contente0
- Direction
- reducede0
GeraniumNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress markedly reduced growth parameters, herb yield, and total chlorophyll content”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
Melatonin alleviated drought-associated reductions in growth parameters, herb yield and total chlorophyll content.
- Treatment
- MTe0
- Outcome
- growth parameters, herb yield, and total chlorophyll contente0
- Direction
- alleviatede0
- Comparator
- Drought stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Drought stress markedly reduced growth parameters, herb yield, and total chlorophyll content; however, MT alleviated these effects”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
Drought reduced stressed-plant herb yield by 59.91% relative to unstressed plants.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The herb yield of the stressed plants was reduced by 59.91% compared to the unstressed plants”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
With melatonin, stressed-plant herb yield was reduced by 14.38% relative to unstressed plants.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The herb yield of the stressed plants was reduced by 59.91% compared to the unstressed plants, while this reduction was only 14.38% when MT was applied”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
Drought increased essential oil percentage in geranium leaves.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“drought enhanced the essential oil percentage in geranium leaves”
e1“geranium leaves”
Claim · model-written summary
Drought reduced geranium oil yield.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the reduction in oil yield caused by drought”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
Melatonin mitigated drought-associated loss of geranium oil yield.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MT application mitigated this reduction and improved both oil yield and oil components”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
Melatonin improved geranium oil components under drought.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MT application mitigated this reduction and improved both oil yield and oil components”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
Melatonin enhanced accumulation of total phenols, glutathione and proline.
- Treatment
- MT treatmente0
- Outcome
- accumulation of total phenols, glutathione, and prolinee0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the MT treatment enhanced the accumulation of total phenols, glutathione, and proline”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
Melatonin improved ascorbate peroxidase, catalase and glutathione reductase activity.
- Treatment
- MT treatmente0
- Outcome
- activity of ascorbate peroxidase, catalase, and glutathione reductasee0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MT treatment enhanced the accumulation of total phenols, glutathione, and proline and improved the activity of ascorbate peroxidase, catalase, and glutathione reductase”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
Melatonin alleviated drought-induced oxidative damage.
- Treatment
- MT treatmente2
- Outcome
- alleviation of drought-induced oxidative damagee0
- Qualifier
- activity of ascorbate peroxidase, catalase, and glutathione reductasee2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“resulting in the alleviation of drought-induced oxidative damage”
e1“geranium (Pelargonium graveolens L.)”
e2“MT treatment enhanced the accumulation of total phenols, glutathione, and proline and improved the activity of ascorbate peroxidase, catalase, and glutathione reductase”
Claim · model-written summary
Under drought, melatonin reduced hydrogen peroxide accumulation by 71.11%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MT reduced both hydrogen peroxide and malondialdehyde accumulation by 71.11 and 48.30%, respectively, under drought”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
Under drought, melatonin reduced malondialdehyde accumulation by 48.30%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MT reduced both hydrogen peroxide and malondialdehyde accumulation by 71.11 and 48.30%, respectively, under drought”
e1“geranium (Pelargonium graveolens L.)”
Claim · model-written summary
Melatonin maintained cellular structure integrity under drought.
- Treatment
- MTe2
- Outcome
- cellular structures’ integritye0
- Qualifier
- hydrogen peroxide and malondialdehyde accumulatione2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“thereby maintaining the cellular structures’ integrity”
e1“geranium (Pelargonium graveolens L.)”
e2“MT reduced both hydrogen peroxide and malondialdehyde accumulation”
The same questions in other papers
drought · quality: oil · GeraniumPositive and negative results
1 in the opposite direction
- negative
drought · physiology: pigments · GeraniumResults agree
1 paper in the same direction as this paper
- negative
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.