Abstract
Soil salinization has emerged as a major factor negatively affecting soil quality and plant productivity. Proline, functioning as an osmotic regulator, has been proposed as an effective strategy for enhancing plant tolerance to salt stress. This study aimed to investigate the effects of exogenous proline on salt tolerance in soybeans. A hydroponic experiment was conducted with different salt treatments (without NaCl, -NaCl; with 100 mM NaCl, +NaCl) and with or without 150 mM proline (+Pro, -Pro). The results showed that proline application alleviated salt stress-induced reductions in plant growth, photosynthetic parameters, and chlorophyll content while aiding recovery from leaf chlorosis. Proline treatment improved ion homeostasis by reducing Na + levels and increasing K + and Ca 2+ contents in the leaves. Salt stress increased malondialdehyde (MDA) and reactive oxygen species (ROS) levels, along with leaf peroxidase (POD) and catalase (CAT) activities, while decreasing superoxide dismutase (SOD) activity. Moreover, salt stress obviously enhanced proline accumulation, accompanied by increases in glutamate (Glu), glutamate-1-semialdehyde (GSA), and pyrroline-5-carboxylate (P5C) content, as well as the activities of pyrroline-5-carboxylate synthase (P5CS) and pyrroline-5-carboxylate reductase (P5CR) in the glutamate pathway, while reducing proline dehydrogenase (ProDH) activity. Exogenous proline treatment further elevated proline content and increased key substances and enzyme activities in both the glutamate (Glu and P5C content, P5CS and P5CR activity) and ornithine (Orn content and OAT activity) pathways while also reducing ProDH activity. Collectively, our results revealed that exogenous proline contributed to an attenuation of salt stress in soybeans by regulating both the glutamate and ornithine pathways to stimulate endogenous proline accumulation, mediate Na + /K + homeostasis, and inhibit oxidative damage. • The proline (Pro) metabolism is different between +NaCl and +NaCl +Pro treatments. • Pro improves salt-tolerance by improving the antioxidant defense system. • Pro helped in optimizing Na + /K + homeostasis to aid in photosynthetic protection.
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Claims 14
Claim · model-written summary
Proline alleviated salt-induced reductions in growth, photosynthesis, and chlorophyll.
- Taxon
- soybean seedlings
Glycine maxt0 - Treatment
- proline applicatione0
- Outcome
- plant growth, photosynthetic parameters, and chlorophyll contente0
- Direction
- alleviatede0
- Comparator
- salt stresse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“proline application alleviated salt stress-induced reductions in plant growth, photosynthetic parameters, and chlorophyll content”
t0“soybean seedlings”
Claim · model-written summary
Proline aided recovery from leaf chlorosis.
- Taxon
- soybean seedlingsGlycine maxt0
- Outcome
- recovery from leaf chlorosise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“while aiding recovery from leaf chlorosis”
t0“soybean seedlings”
Claim · model-written summary
Proline lowered leaf sodium.
- Taxon
- soybean seedlingsGlycine maxt0
- Organ / stage
- leavese0
- Treatment
- Proline treatmente0
- Outcome
- Na + levelse0
- Direction
- reducinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Proline treatment improved ion homeostasis by reducing Na + levels and increasing K + and Ca 2+ contents in the leaves.”
t0“soybean seedlings”
Claim · model-written summary
Proline increased leaf potassium and calcium contents.
- Taxon
- soybean seedlingsGlycine maxt0
- Organ / stage
- leavese0
- Treatment
- Proline treatmente0
- Outcome
- K + and Ca 2+ contentse0
- Direction
- increasinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Proline treatment improved ion homeostasis by reducing Na + levels and increasing K + and Ca 2+ contents in the leaves.”
t0“soybean seedlings”
Claim · model-written summary
Salt stress increased MDA and ROS levels.
- Taxon
- soybean seedlingsGlycine maxt0
- Treatment
- Salt stresse0
- Outcome
- malondialdehyde (MDA) and reactive oxygen species (ROS) levelse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salt stress increased malondialdehyde (MDA) and reactive oxygen species (ROS) levels, along with leaf peroxidase (POD) and catalase (CAT) activities, while decreasing superoxide dismutase (SOD) activity.”
t0“soybean seedlings”
Claim · model-written summary
Salt stress increased leaf POD and CAT activities.
- Taxon
- soybean seedlingsGlycine maxt0
- Treatment
- Salt stresse0
- Outcome
- leaf peroxidase (POD) and catalase (CAT) activitiese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salt stress increased malondialdehyde (MDA) and reactive oxygen species (ROS) levels, along with leaf peroxidase (POD) and catalase (CAT) activities, while decreasing superoxide dismutase (SOD) activity.”
t0“soybean seedlings”
Claim · model-written summary
Salt stress decreased SOD activity.
- Taxon
- soybean seedlingsGlycine maxt0
- Treatment
- Salt stresse0
- Outcome
- superoxide dismutase (SOD) activitye0
- Direction
- decreasinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salt stress increased malondialdehyde (MDA) and reactive oxygen species (ROS) levels, along with leaf peroxidase (POD) and catalase (CAT) activities, while decreasing superoxide dismutase (SOD) activity.”
t0“soybean seedlings”
Claim · model-written summary
Salt stress raised proline, Glu, GSA, and P5C content.
- Taxon
- soybean seedlingsGlycine maxt0
- Treatment
- salt stresse0
- Outcome
- proline accumulation, accompanied by increases in glutamate (Glu), glutamate-1-semialdehyde (GSA), and pyrroline-5-carboxylate (P5C) contente0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“salt stress obviously enhanced proline accumulation, accompanied by increases in glutamate (Glu), glutamate-1-semialdehyde (GSA), and pyrroline-5-carboxylate (P5C) content”
t0“soybean seedlings”
Claim · model-written summary
Salt stress increased P5CS and P5CR activities.
- Taxon
- soybean seedlingsGlycine maxt0
- Outcome
- activities of pyrroline-5-carboxylate synthase (P5CS) and pyrroline-5-carboxylate reductase (P5CR)e0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the activities of pyrroline-5-carboxylate synthase (P5CS) and pyrroline-5-carboxylate reductase (P5CR) in the glutamate pathway, while reducing proline dehydrogenase (ProDH) activity.”
t0“soybean seedlings”
Claim · model-written summary
Salt stress reduced ProDH activity.
- Taxon
- soybean seedlingsGlycine maxt0
- Outcome
- proline dehydrogenase (ProDH) activitye0
- Direction
- reducinge0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“while reducing proline dehydrogenase (ProDH) activity.”
t0“soybean seedlings”
Claim · model-written summary
Exogenous proline further increased endogenous proline content.
- Taxon
- soybean seedlingsGlycine maxt0
- Treatment
- Exogenous proline treatmente0
- Outcome
- proline contente0
- Direction
- elevatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenous proline treatment further elevated proline content and increased key substances and enzyme activities in both the glutamate (Glu and P5C content, P5CS and P5CR activity) and ornithine (Orn content and OAT activity) pathways while also reducing ProDH activity.”
t0“soybean seedlings”
Claim · model-written summary
Exogenous proline increased Glu and P5C contents and P5CS and P5CR activities.
- Taxon
- soybean seedlingsGlycine maxt0
- Treatment
- Exogenous proline treatmente0
- Outcome
- Glu and P5C content, P5CS and P5CR activitye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenous proline treatment further elevated proline content and increased key substances and enzyme activities in both the glutamate (Glu and P5C content, P5CS and P5CR activity) and ornithine (Orn content and OAT activity) pathways while also reducing ProDH activity.”
t0“soybean seedlings”
Claim · model-written summary
Exogenous proline increased Orn content and OAT activity.
- Taxon
- soybean seedlingsGlycine maxt0
- Treatment
- Exogenous proline treatmente0
- Outcome
- Orn content and OAT activitye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenous proline treatment further elevated proline content and increased key substances and enzyme activities in both the glutamate (Glu and P5C content, P5CS and P5CR activity) and ornithine (Orn content and OAT activity) pathways while also reducing ProDH activity.”
t0“soybean seedlings”
Claim · model-written summary
Exogenous proline reduced ProDH activity.
- Taxon
- soybean seedlingsGlycine maxt0
- Treatment
- Exogenous proline treatmente0
- Outcome
- ProDH activitye0
- Direction
- reducinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Exogenous proline treatment further elevated proline content and increased key substances and enzyme activities in both the glutamate (Glu and P5C content, P5CS and P5CR activity) and ornithine (Orn content and OAT activity) pathways while also reducing ProDH activity.”
t0“soybean seedlings”
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See all 41 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.