Abstract
In the present study, the possibility of enhancing cold stress tolerance of young soybean plants (Glycine max [L.] Merr) by exogenous application of 5-aminolevulinic acid (ALA) was investigated. ALA was applied at various concentrations (0, 0.3, 0.6 and 0.9 mM) by seed priming and foliar application method. After ALA treatment, the plants were subjected to cold stress at 10 ± 0.5 °C for 72 h. Cold stress significantly decreased plant growth, relative water content, chlorophyll, photosynthesis and stomatal conductivity, while it increased electrolyte leakage and proline accumulation. ALA at low concentrations (0.3 mM) protected plants against cold stress, enhancing plant height, shoot fresh and dry weight, chlorophyll content, photosynthesis, stomatal conductivity as well as relative water content. Increase of electrolyte leakage was also prevented by 0.6 mM ALA. ALA also enhanced superoxide dismutase and catalase activities at 0.6 mM concentration especially under cold stress conditions. Proline increased with increasing in ALA concentration under both temperature conditions. In most cases, application of ALA by spraying method was better than seed priming method. Results showed that ALA, which is considered as an endogenous plant growth regulator, can be used effectively to protect soybean plants from the damaging effects of cold stress, by enhancing the activity of antioxidative enzymes, protecting cell membrane against reactive oxygen species and finally by promoting chlorophyll synthesis, leading to more intense photosynthesis and more carbon fixation, without any adverse effect on the plant growth.
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Claims 8
Claim · model-written summary
Cold stress decreased soybean growth, water content, chlorophyll, photosynthesis and stomatal conductivity.
- Taxon
- Soybean
Glycine maxt0 - Treatment
- Cold stresse0
- Outcome
- plant growth, relative water content, chlorophyll, photosynthesis and stomatal conductivitye0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Cold stress significantly decreased plant growth, relative water content, chlorophyll, photosynthesis and stomatal conductivity”
t0“Soybean”
Claim · model-written summary
Cold stress increased electrolyte leakage and proline accumulation.
- Taxon
- Soybean
Glycine maxt0 - Treatment
- Cold stresst0
- Outcome
- electrolyte leakage and proline accumulatione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“while it increased electrolyte leakage and proline accumulation”
t0“Soybean against Cold Stress”
Claim · model-written summary
ALA at 0.3 mM enhanced height, shoot biomass, chlorophyll, photosynthesis, stomatal conductivity and relative water content under cold stress.
- Taxon
- Soybean
Glycine maxt0 - Treatment
- ALA at low concentrations (0.3 mM)e0
- Outcome
- plant height, shoot fresh and dry weight, chlorophyll content, photosynthesis, stomatal conductivity as well as relative water contente0
- Direction
- enhancinge0
- Qualifier
- against cold stresse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“ALA at low concentrations (0.3 mM) protected plants against cold stress, enhancing plant height, shoot fresh and dry weight, chlorophyll content, photosynthesis, stomatal conductivity as well as relative water content”
t0“Soybean”
Claim · model-written summary
ALA at 0.6 mM prevented the increase of electrolyte leakage.
- Taxon
- Soybean
Glycine maxt0 - Treatment
- 0.6 mM ALAe0
- Outcome
- electrolyte leakagee0
- Direction
- preventede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Increase of electrolyte leakage was also prevented by 0.6 mM ALA”
t0“Soybean”
Claim · model-written summary
ALA at 0.6 mM enhanced superoxide dismutase and catalase activity, especially under cold stress.
- Taxon
- Soybean
Glycine maxt0 - Treatment
- ALAe0
- Outcome
- superoxide dismutase and catalase activitiese0
- Direction
- enhancede0
- Qualifier
- 0.6 mM concentration especially under cold stress conditionse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“ALA also enhanced superoxide dismutase and catalase activities at 0.6 mM concentration especially under cold stress conditions”
t0“Soybean”
Claim · model-written summary
Proline increased with ALA concentration under both temperature conditions.
- Taxon
- Soybean
Glycine maxt0 - Treatment
- ALA concentratione0
- Outcome
- Prolinee0
- Direction
- increasede0
- Qualifier
- under both temperature conditionse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“Proline increased with increasing in ALA concentration under both temperature conditions”
t0“Soybean”
Claim · model-written summary
ALA spraying generally performed better than seed priming.
- Taxon
- Soybean
Glycine maxt0 - Treatment
- application of ALA by spraying methode0
- Outcome
- bettere0
- Direction
- bettere0
- Comparator
- seed priming methode0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“In most cases, application of ALA by spraying method was better than seed priming method”
t0“Soybean”
Claim · model-written summary
The authors recommend ALA to protect soybean from cold stress through antioxidative and photosynthetic effects.
- Taxon
- soybean plants
Glycine maxe0 - Outcome
- can be used effectively to protect soybean plants from the damaging effects of cold stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.

Verbatim
e0“ALA, which is considered as an endogenous plant growth regulator, can be used effectively to protect soybean plants from the damaging effects of cold stress, by enhancing the activity of antioxidative enzymes, protecting cell membrane against reactive oxygen species and finally by promoting chlorophyll synthesis, leading to more intense photosynthesis and more carbon fixation, without any adverse effect on the plant growth”
The same questions in other papers
5-aminolevulinic acid · physiology: oxidative · Glycine max (soybean)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- negative
- positive
5-aminolevulinic acid · physiology: photosynthesis · Glycine max (soybean)Results agree
1 paper in the same direction as this paper
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5-aminolevulinic acid · physiology: antioxidant enzymes · Glycine max (soybean)Results agree
1 paper in the same direction as this paper
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cold · physiology: photosynthesis · Glycine max (soybean)Results differ
7 papers in the same direction as this paper
- negative
- no effect
- negative
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See all 8 papers →cold · physiology: oxidative · Glycine max (soybean)Positive and negative results
4 papers in the same direction as this paper · 1 in the opposite direction
- positive
- negative
- negative
2 papers more in this group
See all 6 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.