Abstract
Due to climate change, heat stress is becoming one of the most disastrous abiotic stresses and responsible for huge crop losses in different regions of the world. Adverse effects of heat stress can be encountered by the use of phytohormones and salicylic acid (SA) is one of those hormones having capability to protect plants from heat stress. Current research work was planned to explore the defensive role of exogenously applied SA in barley cultivars under high temperature. For this purpose, two weeks old plants of four barley cultivars (Jau-87, B-10007, B-14003 and B-14037) were foliar sprayed with SA (2 mM and 5 mM) for 24 hours and then were exposed to heat stress (42 °C). Our results showed that heat exposure made a prominent decrease in chlorophyll contents, carotenoids, relative water contents, antioxidant enzymes activities (superoxide dismutase, peroxidase and catalase) and anthocyanin activity while increased lipid peroxidation (malondialdehyde), hydrogen peroxide (H2O2) contents and proline accumulation. Foliar application of SA enhanced plants photosynthetic pigments (chlorophyll a, b and total), RWC, proline, and anthocyanin under control and stressed conditions. SA pre-treatment under heat stress reduced H2O2 and MDA levels whereas activities of reactive oxygen species (ROS) scavenging enzymes were elevated by all tested SA concentrations. These results suggest that SA can efficiently remove H2O2 by increasing activity of above mentioned enzymes hence reducing oxidative stress and malondialdehyde (MDA) contents. Proline, an important amino acid that acts as an anti-oxidative system in plants also highly accumulated in SA co-treated heat-stressed plants. Our results also showed that 2mM SA is more effective in protecting barley plants under heat stress as compared to 5mM SA. This concluded that defensive nature of SA regulates different physiological and biochemical processes to induce heat tolerance in barley.
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Claims 9
Claim · model-written summary
Heat exposure reduced chlorophyll and carotenoid contents and relative water content.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaret0 - Treatment
- heat exposuree0
- Outcome
- chlorophyll contents, carotenoids, relative water contentse0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“heat exposure made a prominent decrease in chlorophyll contents, carotenoids, relative water contents”
t0“Barley”
Claim · model-written summary
Heat exposure reduced superoxide dismutase, peroxidase, catalase, and anthocyanin activity.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- heat exposuree0
- Outcome
- antioxidant enzymes activities (superoxide dismutase, peroxidase and catalase) and anthocyanin activitye0
- Direction
- decreasee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“heat exposure made a prominent decrease in chlorophyll contents, carotenoids, relative water contents, antioxidant enzymes activities (superoxide dismutase, peroxidase and catalase) and anthocyanin activity”
t0“Barley”
Claim · model-written summary
Heat exposure increased malondialdehyde, hydrogen peroxide, and proline accumulation.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- heat exposuree0
- Outcome
- lipid peroxidation (malondialdehyde), hydrogen peroxide (H2O2) contents and proline accumulatione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“heat exposure made a prominent decrease in chlorophyll contents, carotenoids, relative water contents, antioxidant enzymes activities (superoxide dismutase, peroxidase and catalase) and anthocyanin activity while increased lipid peroxidation (malondialdehyde), hydrogen peroxide (H2O2) contents and proline accumulation”
t0“Barley”
Claim · model-written summary
Salicylic acid increased chlorophyll pigments and relative water content under control and heat conditions.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- Foliar application of SAe0
- Outcome
- photosynthetic pigments (chlorophyll a, b and total), RWCe0
- Direction
- enhancede0
- Qualifier
- under control and stressed conditionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar application of SA enhanced plants photosynthetic pigments (chlorophyll a, b and total), RWC, proline, and anthocyanin under control and stressed conditions”
t0“Barley”
Claim · model-written summary
Salicylic acid increased proline and anthocyanin under control and heat conditions.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- Foliar application of SAe0
- Outcome
- proline, and anthocyanine0
- Direction
- enhancede0
- Qualifier
- under control and stressed conditionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar application of SA enhanced plants photosynthetic pigments (chlorophyll a, b and total), RWC, proline, and anthocyanin under control and stressed conditions”
t0“Barley”
Claim · model-written summary
Salicylic acid pretreatment under heat stress reduced hydrogen peroxide and malondialdehyde.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- SA pre-treatment under heat stresse0
- Outcome
- H2O2 and MDA levelse0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“SA pre-treatment under heat stress reduced H2O2 and MDA levels”
t0“Barley”
Claim · model-written summary
All tested salicylic acid concentrations elevated ROS-scavenging enzyme activities under heat stress.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- all tested SA concentrationse0
- Outcome
- activities of reactive oxygen species (ROS) scavenging enzymese0
- Direction
- elevatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“activities of reactive oxygen species (ROS) scavenging enzymes were elevated by all tested SA concentrations”
t0“Barley”
Claim · model-written summary
Proline accumulated highly in salicylic-acid-cotreated heat-stressed plants.
- Taxon
- barleyHordeum vulgaret0
- Treatment
- SA co-treated heat-stressede0
- Outcome
- Prolinee0
- Direction
- highly accumulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Proline, an important amino acid that acts as an anti-oxidative system in plants also highly accumulated in SA co-treated heat-stressed plants”
t0“Barley”
Claim · model-written summary
The 2mM salicylic acid treatment protected heat-stressed barley more effectively than 5mM.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- 2mM SAe0
- Outcome
- protecting barley plants under heat stresse0
- Direction
- more effectivee0
- Comparator
- 5mM SAe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“2mM SA is more effective in protecting barley plants under heat stress as compared to 5mM SA”
The same questions in other papers
salicylic acid · physiology: photosynthesis · Hordeum vulgare (barley)Results differ
4 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
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See all 6 papers →salicylic acid · physiology: osmolytes · Hordeum vulgare (barley)Results agree
5 papers in the same direction as this paper
- positive
- positive
- positive
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See all 6 papers →salicylic acid · physiology: oxidative · Hordeum vulgare (barley)Results agree
14 papers in the same direction as this paper
- positive
- positive
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See all 15 papers →heat · physiology: antioxidant enzymes · Hordeum vulgare (barley)Results differ
2 papers in the same direction as this paper · 1 in the opposite direction
- positive
- negative
- negative
heat · physiology: pigments · Hordeum vulgare (barley)Results differ
5 papers in the same direction as this paper · 1 in the opposite direction
- positive
- negative
- negative
3 papers more in this group
See all 7 papers →heat · physiology: oxidative · Hordeum vulgare (barley)Positive and negative results
2 in the opposite direction
- negative
- negative
heat · physiology: osmolytes · Hordeum vulgare (barley)Positive and negative results
3 papers in the same direction as this paper · 1 in the opposite direction
- negative
- positive
- positive
1 paper more in this group
See all 5 papers →application · physiology: osmolytes · Hordeum vulgare (barley)Results agree
4 papers in the same direction as this paper
- positive
- positive
- positive
1 paper more in this group
See all 5 papers →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.