Abstract
Global warming negatively affects plant growth due to the detrimental effects of high temperature-induced heat stress. Rhizobium inoculation (RI) and exogenous melatonin (MT) have shown a positive role in resisting abiotic stress. However, their synergistic effect on avoiding heat-induced damages in Medicago truncatula has not been studied yet. Hence, the objective of the present study was to evaluate the impact of these amendments (RI and MT) to ameliorate the heat damages in Medicago truncatula . The study was comprised of two factors: (1) heat-induced stress: (i) optimum temperature (26 ± 1°C): (23 ± 1°C) (day: night), (ii) moderate heat (35 ± 1°C): (28 ± 1°C), and (iii) severe heat (41 ± 1°C): (35 ± 1°C) for 72 h, and (2) amendments: (i) no RI + no MT (NRI + NMT), (ii) Rhizobium inoculation (RI), (iii) 60 μM melatonin (MT), and (iii) RI + MT. Results showed that the combined application of RI and MT was better than their individual applications, as it prevented heat-induced membrane damages by declining the hydrogen peroxide (34.22% and 29.78%), superoxide anion radical (29.49% and 26.71%), malondialdehyde contents (26.43% and 21.96%), and lipoxygenase activity (44.75% and 25.51%) at both heat stress levels as compared to NRI + NMT. Moreover, RI + MT treated plants showed higher antioxidative and methylglyoxal detoxification enzymes (Gly I and Gly II) activities under heat stress. While, NRI + NMT treated plants showed a higher level of methylglyoxal contents (47.99% and 46.71%) under both levels of heat stress. Relative to NRI + NMT plants, RI + MT pretreated plants exhibited improved heat tolerance as indicated by higher chlorophyll (37.42% and 43.52%), carotenoid contents (32.41% and 47.08%), and photosynthetic rate (42.62% and 64.63%), under moderate and severe heat stress, respectively. Furthermore, RI + MT pretreated plants had considerably higher indole-3 acetic acid and abscisic acid concentrations under moderate (54.02% and 53.92%) and severe (68.36% and 64.61%) heat stress conditions. Similarly, plant dry biomass, NPK uptake, nitric oxide, and nitrate reductase activity were high in RI + MT treated plants, under both levels of stress. Therefore, this study advocates the positive synergistic effect of RI and MT pretreatment against moderate and severe heat-induced stress and for possible maintenance of plant growth under changing scenarios of global warming.
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Claims 14
Claim · model-written summary
Combined RI and MT lowered hydrogen peroxide (34.22% and 29.78%) at both heat levels relative to NRI + NMT plants.
- Taxon
- Medicago truncatula
Medicago truncatulae2 - Treatment
- combined application of RI and MTe1
- Outcome
- hydrogen peroxidee1
- Direction
- declininge1
- Value
- 34.22% and 29.78%e1
- Comparator
- NRI + NMTe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the combined application of RI and MT was better than their individual applications, as it prevented heat-induced membrane damages by declining the hydrogen peroxide (34.22% and 29.78%), superoxide anion radical (29.49% and 26.71%), malondialdehyde contents (26.43% and 21.96%), and lipoxygenase activity (44.75% and 25.51%) at both heat stress levels as compared to NRI + NMT”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
Combined RI and MT lowered superoxide anion radical (29.49% and 26.71%) relative to NRI + NMT plants.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- combined application of RI and MTe1
- Outcome
- superoxide anion radicale1
- Direction
- declininge1
- Value
- 29.49% and 26.71%e1
- Comparator
- NRI + NMTe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the combined application of RI and MT was better than their individual applications, as it prevented heat-induced membrane damages by declining the hydrogen peroxide (34.22% and 29.78%), superoxide anion radical (29.49% and 26.71%), malondialdehyde contents (26.43% and 21.96%), and lipoxygenase activity (44.75% and 25.51%) at both heat stress levels as compared to NRI + NMT”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
Combined RI and MT lowered malondialdehyde contents (26.43% and 21.96%) relative to NRI + NMT plants.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- combined application of RI and MTe1
- Outcome
- malondialdehyde contentse1
- Direction
- declininge1
- Value
- 26.43% and 21.96%e1
- Comparator
- NRI + NMTe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the combined application of RI and MT was better than their individual applications, as it prevented heat-induced membrane damages by declining the hydrogen peroxide (34.22% and 29.78%), superoxide anion radical (29.49% and 26.71%), malondialdehyde contents (26.43% and 21.96%), and lipoxygenase activity (44.75% and 25.51%) at both heat stress levels as compared to NRI + NMT”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
Combined RI and MT lowered lipoxygenase activity (44.75% and 25.51%) relative to NRI + NMT plants.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- combined application of RI and MTe1
- Outcome
- lipoxygenase activitye1
- Direction
- declininge1
- Value
- 44.75% and 25.51%e1
- Comparator
- NRI + NMTe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the combined application of RI and MT was better than their individual applications, as it prevented heat-induced membrane damages by declining the hydrogen peroxide (34.22% and 29.78%), superoxide anion radical (29.49% and 26.71%), malondialdehyde contents (26.43% and 21.96%), and lipoxygenase activity (44.75% and 25.51%) at both heat stress levels as compared to NRI + NMT”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
RI + MT pretreated plants had higher chlorophyll (37.42% and 43.52%) than NRI + NMT plants under moderate and severe heat.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- RI + MTe3
- Outcome
- chlorophylle3
- Direction
- highere3
- Value
- 37.42% and 43.52%e3
- Qualifier
- moderate and severe heat stresse3
- Comparator
- NRI + NMTe3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Relative to NRI + NMT plants, RI + MT pretreated plants exhibited improved heat tolerance as indicated by higher chlorophyll (37.42% and 43.52%), carotenoid contents (32.41% and 47.08%), and photosynthetic rate (42.62% and 64.63%), under moderate and severe heat stress, respectively”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
RI + MT pretreated plants had higher carotenoid contents (32.41% and 47.08%) than NRI + NMT plants under moderate and severe heat.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- RI + MTe3
- Outcome
- carotenoid contentse3
- Direction
- highere3
- Value
- 32.41% and 47.08%e3
- Qualifier
- moderate and severe heat stresse3
- Comparator
- NRI + NMTe3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Relative to NRI + NMT plants, RI + MT pretreated plants exhibited improved heat tolerance as indicated by higher chlorophyll (37.42% and 43.52%), carotenoid contents (32.41% and 47.08%), and photosynthetic rate (42.62% and 64.63%), under moderate and severe heat stress, respectively”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
RI + MT pretreated plants had higher photosynthetic rate (42.62% and 64.63%) than NRI + NMT plants under moderate and severe heat.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- RI + MTe3
- Outcome
- photosynthetic ratee3
- Direction
- highere3
- Value
- 42.62% and 64.63%e3
- Qualifier
- moderate and severe heat stresse3
- Comparator
- NRI + NMTe3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“Relative to NRI + NMT plants, RI + MT pretreated plants exhibited improved heat tolerance as indicated by higher chlorophyll (37.42% and 43.52%), carotenoid contents (32.41% and 47.08%), and photosynthetic rate (42.62% and 64.63%), under moderate and severe heat stress, respectively”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
RI + MT pretreated plants had higher indole-3 acetic acid and abscisic acid concentrations under moderate heat (54.02% and 53.92%).
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- heat stress conditionse4
- Outcome
- indole-3 acetic acid and abscisic acid concentrationse4
- Direction
- highere4
- Value
- 54.02% and 53.92%e4
- Qualifier
- moderatee4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“RI + MT pretreated plants had considerably higher indole-3 acetic acid and abscisic acid concentrations under moderate (54.02% and 53.92%) and severe (68.36% and 64.61%) heat stress conditions”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
RI + MT pretreated plants had higher indole-3 acetic acid and abscisic acid concentrations under severe heat (68.36% and 64.61%).
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- heat stress conditionse4
- Outcome
- indole-3 acetic acid and abscisic acid concentrationse4
- Direction
- highere4
- Value
- 68.36% and 64.61%e4
- Qualifier
- severee4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“RI + MT pretreated plants had considerably higher indole-3 acetic acid and abscisic acid concentrations under moderate (54.02% and 53.92%) and severe (68.36% and 64.61%) heat stress conditions”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
Plant dry biomass, NPK uptake and nitric oxide were high in RI + MT treated plants under both stress levels.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- RI + MTe5
- Outcome
- plant dry biomass, NPK uptake, nitric oxidee5
- Direction
- highe5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“plant dry biomass, NPK uptake, nitric oxide, and nitrate reductase activity were high in RI + MT treated plants, under both levels of stress”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
Nitrate reductase activity was high in RI + MT treated plants under both stress levels.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- RI + MTe5
- Outcome
- nitrate reductase activitye5
- Direction
- highe5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“plant dry biomass, NPK uptake, nitric oxide, and nitrate reductase activity were high in RI + MT treated plants, under both levels of stress”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
Combined RI and MT prevented heat-induced membrane damage better than the individual applications.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- combined application of RI and MTe1
- Outcome
- heat-induced membrane damagese1
- Direction
- preventede1
- Comparator
- individual applicationse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the combined application of RI and MT was better than their individual applications, as it prevented heat-induced membrane damages by declining the hydrogen peroxide (34.22% and 29.78%), superoxide anion radical (29.49% and 26.71%), malondialdehyde contents (26.43% and 21.96%), and lipoxygenase activity (44.75% and 25.51%) at both heat stress levels as compared to NRI + NMT”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
RI + MT treated plants had higher antioxidative and methylglyoxal detoxification enzyme (Gly I and Gly II) activities under heat stress.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- RI + MTe6
- Gene
- Gly I and Gly IIe6
- Outcome
- antioxidative and methylglyoxal detoxification enzymes (Gly I and Gly II) activitiese6
- Direction
- highere6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“RI + MT treated plants showed higher antioxidative and methylglyoxal detoxification enzymes (Gly I and Gly II) activities under heat stress”
e2“ameliorate the heat damages in Medicago truncatula”
Claim · model-written summary
NRI + NMT treated plants had higher methylglyoxal contents (47.99% and 46.71%) under both heat levels.
- Taxon
- Medicago truncatulaMedicago truncatulae2
- Treatment
- NRI + NMTe7
- Outcome
- methylglyoxal contentse7
- Direction
- highere7
- Value
- 47.99% and 46.71%e7
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“NRI + NMT treated plants showed a higher level of methylglyoxal contents (47.99% and 46.71%) under both levels of heat stress”
e2“ameliorate the heat damages in Medicago truncatula”
The same questions in other papers
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melatonin · physiology: pigments · Medicago truncatula (barrel medic)Results agree
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melatonin · growth · Medicago truncatula (barrel medic)Results agree
1 paper in the same direction as this paper
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inoculation · growth · Medicago truncatula (barrel medic)Positive and negative results
8 papers in the same direction as this paper · 2 in the opposite direction
- negative
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inoculation · physiology: photosynthesis · Medicago truncatula (barrel medic)Results agree
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8 of 9 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.