Abstract
Abstract Melatonin plays an important role in the enhancement of plant tolerance to drought stress. The underlying mechanisms of this melatonin-induced protection of the photosynthetic apparatus against drought stress are still not fully understood in maize (Zea mays L.). This study investigated the effects of 100 and 200 μM exogenous melatonin additions on the photosynthetic electron transport process in maize seedlings under drought stress. The chlorophyll a fluorescence transient (OJIP) and modulated 820 nm reflection (MR) analysis showed that drought stress damaged the donor and acceptor side of photosystem II (PSII). Furthermore, the function of PSII reaction centers and the quantum yields of PSI and PSII were significant reduced. These fluorescence parameters were restored in melatonin-treated plants. Energy conversion analysis indicated that melatonin-treated plants maintained a stronger ability to ensure high photosynthetic capacity, as evidenced by higher PSI photochemical quantum yield Y(I) and PSII photochemical quantum yield Y(II). Melatonin treatment decreased the regulated energy dissipation Y(NPQ) and non-regulated energy dissipation Y(NO) in PSII. Moreover, melatonin treatment mitigated the limitations of both the acceptor-side and donor-side of PSI under drought stress, as indicated by lower PSI acceptor side limitation Y(NA) and PSI donor side limitation Y(ND). In addition, 100 μM melatonin was the more effective concentration to alleviate the damage to the photosynthetic apparatus. Thus, exogenous melatonin alleviated the drought stress-induced damage of the photosynthetic apparatus in maize by improving the photosynthetic electron transport efficiency between both photosystems and by enhancing the quantum yields of PSI and PSII photochemistry.
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Claims 9
Claim · model-written summary
Drought damaged both donor and acceptor sides of PSII.
- Treatment
- drought stresse2
- Outcome
- donor and acceptor side of photosystem II (PSII)e0
- Direction
- damagede0
Zea maysNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“drought stress damaged the donor and acceptor side of photosystem II (PSII).”
t0“maize”
e2“drought stress damaged the donor and acceptor side of photosystem II (PSII).”
Claim · model-written summary
Drought significantly reduced PSII reaction-center function and PSI and PSII quantum yields.
- Treatment
- drought stresse2
- Outcome
- function of PSII reaction centers and the quantum yields of PSI and PSIIe0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the function of PSII reaction centers and the quantum yields of PSI and PSII were significant reduced.”
t0“maize”
e2“drought stress damaged the donor and acceptor side of photosystem II (PSII).”
Claim · model-written summary
Melatonin restored drought-affected fluorescence parameters.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These fluorescence parameters were restored in melatonin-treated plants.”
t0“maize”
Claim · model-written summary
Melatonin-treated maize had higher PSI photochemical quantum yield Y(I).
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin-treated plants maintained a stronger ability to ensure high photosynthetic capacity, as evidenced by higher PSI photochemical quantum yield Y(I) and PSII photochemical quantum yield Y(II).”
t0“maize”
Claim · model-written summary
Melatonin-treated maize had higher PSII photochemical quantum yield Y(II).
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin-treated plants maintained a stronger ability to ensure high photosynthetic capacity, as evidenced by higher PSI photochemical quantum yield Y(I) and PSII photochemical quantum yield Y(II).”
t0“maize”
Claim · model-written summary
Melatonin lowered regulated and non-regulated PSII energy dissipation.
- Treatment
- Melatonin treatmente0
- Outcome
- regulated energy dissipation Y(NPQ) and non-regulated energy dissipation Y(NO)e0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Melatonin treatment decreased the regulated energy dissipation Y(NPQ) and non-regulated energy dissipation Y(NO) in PSII.”
t0“maize”
Claim · model-written summary
Melatonin lowered both acceptor- and donor-side PSI limitations under drought.
- Treatment
- melatonin treatmente0
- Outcome
- PSI acceptor side limitation Y(NA) and PSI donor side limitation Y(ND)e0
- Direction
- lowere0
- Qualifier
- under drought stresse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“melatonin treatment mitigated the limitations of both the acceptor-side and donor-side of PSI under drought stress, as indicated by lower PSI acceptor side limitation Y(NA) and PSI donor side limitation Y(ND).”
t0“maize”
Claim · model-written summary
100 μM melatonin was more effective for protecting the photosynthetic apparatus.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“100 μM melatonin was the more effective concentration to alleviate the damage to the photosynthetic apparatus.”
t0“maize”
Claim · model-written summary
The authors attributed melatonin protection to improved electron transport and PSI and PSII photochemical yields.
- Treatment
- exogenous melatonine0
- Outcome
- drought stress-induced damage of the photosynthetic apparatuse0
- Qualifier
- improving the photosynthetic electron transport efficiency between both photosystemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“exogenous melatonin alleviated the drought stress-induced damage of the photosynthetic apparatus in maize by improving the photosynthetic electron transport efficiency between both photosystems and by enhancing the quantum yields of PSI and PSII photochemistry.”
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See all 121 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.