Abstract
Problem statement: Drought stress as a major adverse factor can lower leaf water potential, leading to reduced turgor and some other responses and ultimately lower crop productivity in arid and semi arid zones. Sunflower is one of the main oil seed crops in Iran, where drought stress is the most limiting factor. Drought stress tolerance requires the activation of complex metabolic activities including antioxidative pathways, especially Activated Oxygen Species (AOS) and scavenging systems within the cells which can contribute to continued growth under drought stress. Approach: To evaluate the effect of limited irrigation systems and potassium fertilizer on grain yield, antioxidant enzymes and lipid peroxidation biomarker (MDA), the crop was sown in the Research Farm of College of Agriculture, Islamic Azad University, Karaj Branch in 2009. The experimental treatments were arranged as split plots based on a Randomized Complete Block Design with three replications. The main plots were allocated to three different irrigation regimes. The irrigation regimes comprised of: Full Irrigation (IR 1 ), Moderate drought stress (IR 5 ) and Severe drought stress (IR 2 ). The subplots were allocated to four potassium chemical fertilizer (Potassium nitrate) consisting of K 1 = 25, K 2 = 50, K 3 = 75 and K 4 = 100% recommended. Results: Plants under drought stress and potassium levels showed a significant increase and decrease, respectively, in SOD, CAT and GPX activity and MDA in compared to control plants. In this context, plants with higher levels of potassium showed higher resistance to drought stress conditions and higher yield and dry matter allocation to grain filling process i.e. harvest index. Results of this study suggested that drought stress leads to production of oxygen radicals, which results in increased lipid peroxidation (MDA biomarker) and oxidative stress in the plant. Conclusion: The scavenging of AOS by the scavenging system especially by SOD, CAT and GPX was done well and damage to membranes or MDA was controlled at higher levels of potassium.
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Claims 8
Claim · model-written summary
Drought stress significantly increased SOD, CAT and GPX activity in sunflower compared with control plants.
- Taxon
- Sunflower
Helianthus annuust0 - Treatment
- drought stresse0
- Outcome
- SOD, CAT and GPX activitye0
- Direction
- increasee0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Sunflower (Helianthus annuus L.)”
e0“Plants under drought stress and potassium levels showed a significant increase and decrease, respectively, in SOD, CAT and GPX activity and MDA in compared to control plants”
Claim · model-written summary
Drought stress significantly increased MDA in sunflower compared with control plants.
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- drought stresse0
- Outcome
- MDAe0
- Direction
- increasee0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Sunflower (Helianthus annuus L.)”
e0“Plants under drought stress and potassium levels showed a significant increase and decrease, respectively, in SOD, CAT and GPX activity and MDA in compared to control plants”
Claim · model-written summary
Higher potassium levels significantly decreased SOD, CAT and GPX activity in sunflower compared with control plants.
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- potassium levelse0
- Outcome
- SOD, CAT and GPX activitye0
- Direction
- decreasee0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Sunflower (Helianthus annuus L.)”
e0“Plants under drought stress and potassium levels showed a significant increase and decrease, respectively, in SOD, CAT and GPX activity and MDA in compared to control plants”
Claim · model-written summary
Higher potassium levels significantly decreased MDA in sunflower compared with control plants.
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- potassium levelse0
- Outcome
- MDAe0
- Direction
- decreasee0
- Comparator
- control plantse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Sunflower (Helianthus annuus L.)”
e0“Plants under drought stress and potassium levels showed a significant increase and decrease, respectively, in SOD, CAT and GPX activity and MDA in compared to control plants”
Claim · model-written summary
Sunflower plants with higher potassium levels showed higher resistance to drought stress.
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- higher levels of potassiume0
- Outcome
- resistance to drought stress conditionse0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Sunflower (Helianthus annuus L.)”
e0“plants with higher levels of potassium showed higher resistance to drought stress conditions and higher yield and dry matter allocation to grain filling process i.e. harvest index”
Claim · model-written summary
Sunflower plants with higher potassium levels had higher yield and higher dry matter allocation to grain filling (harvest index).
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- higher levels of potassiume0
- Outcome
- yield and dry matter allocation to grain filling process i.e. harvest indexe0
- Direction
- highere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Sunflower (Helianthus annuus L.)”
e0“plants with higher levels of potassium showed higher resistance to drought stress conditions and higher yield and dry matter allocation to grain filling process i.e. harvest index”
Claim · model-written summary
The authors suggest drought stress leads to production of oxygen radicals, which increases lipid peroxidation (MDA) and oxidative stress in the plant.
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- drought stresse0
- Compound
- oxygen radicalse0
- Outcome
- increased lipid peroxidation (MDA biomarker) and oxidative stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Sunflower (Helianthus annuus L.)”
e0“drought stress leads to production of oxygen radicals, which results in increased lipid peroxidation (MDA biomarker) and oxidative stress in the plant”
Claim · model-written summary
The authors conclude that the scavenging system, especially SOD, CAT and GPX, worked well and membrane damage (MDA) was controlled at higher potassium levels.
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- higher levels of potassiume0
- Gene
- SOD, CAT and GPXe0
- Outcome
- damage to membranes or MDAe0
- Qualifier
- scavenging of AOSe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Sunflower (Helianthus annuus L.)”
e0“The scavenging of AOS by the scavenging system especially by SOD, CAT and GPX was done well and damage to membranes or MDA was controlled at higher levels of potassium”
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1 paper in the same direction as this paper
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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.