Abstract
Rice (Oryza sativa L.) seedling raising is a vital step in rice cultivation. Salt stress severely impairs the growth of rice seedlings, whereas 5-aminolevulinic acid (5-ALA) plays a crucial role in plant responses to various abiotic stresses. In this study, we combined agronomic practices with chemical regulation. We selected two sowing methods, namely drill sowing and broadcast sowing. Treatments were applied at the three-leaf stage. These included foliar application of 40 mg·L− 1 5-aminolevulinic acid (5-ALA) and application of 0.4% (w/w) NaCl based on dry soil weight. This resulted in a soil electrical conductivity of 5500 ± 50 µS·cm− 1. Three biological replicates were set for each treatment, and sampling was conducted on the 3rd, 6th, and 9th days after salt stress imposition. The results showed that, under salt stress, excessive accumulation of Na+ and Cl− in rice seedling leaves damaged the photosynthetic apparatus and significantly inhibited seedling growth. Exogenous foliar application of 5-ALA promoted the synthesis of photosynthetic pigments by increasing the content of precursors for chloroplast synthesis. Meanwhile, 5-ALA increased K+ and Ca2+ levels significantly and reduced Na+ content by 26.96%. It also enhanced antioxidant enzyme activity and alleviated oxidative damage. As a result, gas exchange and chloroplast fluorescence parameters in seedlings improved, the photosynthetic rate increased by 49.39%, and carbohydrate accumulation was enhanced. Compared with broadcast sowing, drill sowing combined with 5-ALA application resulted in higher levels of chloroplast synthesis precursors and greater carbohydrate accumulation. These reserves provided additional energy for chlorophyll synthesis and for the repair of the photosynthetic apparatus under salt stress. This enhanced peroxide-scavenging capacity, maintained photosynthetic apparatus stability, improved ion homeostasis, and gave drill sowing stronger salt tolerance than broadcast sowing. Taken together, drill sowing and foliar application of 5-ALA significantly maintain the stability of the photosynthetic system and ion homeostasis in rice seedlings under salt stress. This enhances salt tolerance. These findings lay a theoretical foundation for future field trials and the use of saline-alkali soils.
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Claims 15
Claim · model-written summary
Under salt stress, excessive Na+ accumulation significantly inhibited rice seedling growth.
- Taxon
- rice
Oryza sativat0 - Treatment
- salt stresse3
- Compound
- Na+e1
- Outcome
- seedling growthe2
- Direction
- inhibitede2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e1“excessive accumulation of Na+”
e2“significantly inhibited seedling growth”
e3“The results showed that, under salt stress”
Claim · model-written summary
Foliar 5-ALA promoted synthesis of photosynthetic pigments in rice seedlings.
- Taxon
- riceOryza sativat0
- Treatment
- foliar application of 5-ALAe3
- Outcome
- synthesis of photosynthetic pigmentse3
- Direction
- promotede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e3“Exogenous foliar application of 5-ALA promoted the synthesis of photosynthetic pigments by increasing the content of precursors for chloroplast synthesis”
Claim · model-written summary
5-ALA significantly increased K+ and Ca2+ levels in rice seedlings under salt stress.
- Taxon
- riceOryza sativat0
- Treatment
- 5-ALAe4
- Outcome
- K+ and Ca2+ levelse4
- Direction
- increasede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e4“Meanwhile, 5-ALA increased K+ and Ca2+ levels significantly and reduced Na+ content by 26.96%”
Claim · model-written summary
5-ALA reduced Na+ content in rice seedlings by 26.96%.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e4“Meanwhile, 5-ALA increased K+ and Ca2+ levels significantly and reduced Na+ content by 26.96%”
Claim · model-written summary
5-ALA enhanced antioxidant enzyme activity in rice seedlings under salt stress.
- Taxon
- riceOryza sativat0
- Treatment
- foliar application of 5-ALAe3
- Outcome
- antioxidant enzyme activitye5
- Direction
- enhancede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e3“Exogenous foliar application of 5-ALA promoted the synthesis of photosynthetic pigments by increasing the content of precursors for chloroplast synthesis”
e5“It also enhanced antioxidant enzyme activity and alleviated oxidative damage”
Claim · model-written summary
5-ALA alleviated oxidative damage in rice seedlings under salt stress.
- Taxon
- riceOryza sativat0
- Treatment
- foliar application of 5-ALAe3
- Outcome
- oxidative damagee5
- Direction
- alleviatede5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e3“Exogenous foliar application of 5-ALA promoted the synthesis of photosynthetic pigments by increasing the content of precursors for chloroplast synthesis”
e5“It also enhanced antioxidant enzyme activity and alleviated oxidative damage”
Claim · model-written summary
5-ALA improved gas exchange and chloroplast fluorescence parameters of rice seedlings.
- Taxon
- riceOryza sativat0
- Treatment
- foliar application of 5-ALAe3
- Outcome
- gas exchange and chloroplast fluorescence parameterse6
- Direction
- improvede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e3“Exogenous foliar application of 5-ALA promoted the synthesis of photosynthetic pigments by increasing the content of precursors for chloroplast synthesis”
e6“As a result, gas exchange and chloroplast fluorescence parameters in seedlings improved, the photosynthetic rate increased by 49.39%, and carbohydrate accumulation was enhanced”
Claim · model-written summary
5-ALA increased the photosynthetic rate of rice seedlings by 49.39%.
- Taxon
- riceOryza sativat0
- Treatment
- foliar application of 5-ALAe3
- Outcome
- photosynthetic ratee6
- Direction
- increasede6
- Value
- 49.39%e6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e3“Exogenous foliar application of 5-ALA promoted the synthesis of photosynthetic pigments by increasing the content of precursors for chloroplast synthesis”
e6“As a result, gas exchange and chloroplast fluorescence parameters in seedlings improved, the photosynthetic rate increased by 49.39%, and carbohydrate accumulation was enhanced”
Claim · model-written summary
5-ALA enhanced carbohydrate accumulation in rice seedlings.
- Taxon
- riceOryza sativat0
- Treatment
- foliar application of 5-ALAe3
- Outcome
- carbohydrate accumulatione6
- Direction
- enhancede6
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e3“Exogenous foliar application of 5-ALA promoted the synthesis of photosynthetic pigments by increasing the content of precursors for chloroplast synthesis”
e6“As a result, gas exchange and chloroplast fluorescence parameters in seedlings improved, the photosynthetic rate increased by 49.39%, and carbohydrate accumulation was enhanced”
Claim · model-written summary
Drill sowing with 5-ALA gave higher levels of chloroplast synthesis precursors than broadcast sowing.
- Taxon
- riceOryza sativat0
- Treatment
- drill sowing combined with 5-ALA applicatione7
- Outcome
- levels of chloroplast synthesis precursorse7
- Direction
- highere7
- Comparator
- broadcast sowinge7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e7“Compared with broadcast sowing, drill sowing combined with 5-ALA application resulted in higher levels of chloroplast synthesis precursors and greater carbohydrate accumulation”
Claim · model-written summary
Drill sowing with 5-ALA gave greater carbohydrate accumulation than broadcast sowing.
- Taxon
- riceOryza sativat0
- Treatment
- drill sowing combined with 5-ALA applicatione7
- Outcome
- carbohydrate accumulatione7
- Direction
- greatere7
- Comparator
- broadcast sowinge7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e7“Compared with broadcast sowing, drill sowing combined with 5-ALA application resulted in higher levels of chloroplast synthesis precursors and greater carbohydrate accumulation”
Claim · model-written summary
Drill sowing gave rice stronger salt tolerance than broadcast sowing.
- Taxon
- riceOryza sativat0
- Treatment
- drill sowinge0
- Outcome
- salt tolerancee0
- Direction
- strongere0
- Comparator
- broadcast sowinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e0“This enhanced peroxide-scavenging capacity, maintained photosynthetic apparatus stability, improved ion homeostasis, and gave drill sowing stronger salt tolerance than broadcast sowing”
Claim · model-written summary
Drill sowing with 5-ALA enhanced peroxide-scavenging capacity of rice seedlings under salt stress.
- Taxon
- riceOryza sativat0
- Treatment
- drill sowing combined with 5-ALA applicatione7
- Outcome
- peroxide-scavenging capacitye0
- Direction
- enhancede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e7“Compared with broadcast sowing, drill sowing combined with 5-ALA application resulted in higher levels of chloroplast synthesis precursors and greater carbohydrate accumulation”
e0“This enhanced peroxide-scavenging capacity, maintained photosynthetic apparatus stability, improved ion homeostasis, and gave drill sowing stronger salt tolerance than broadcast sowing”
Claim · model-written summary
Drill sowing with 5-ALA maintained photosynthetic apparatus stability in rice seedlings under salt stress.
- Taxon
- riceOryza sativat0
- Treatment
- drill sowing combined with 5-ALA applicatione7
- Outcome
- photosynthetic apparatus stabilitye0
- Direction
- maintainede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e7“Compared with broadcast sowing, drill sowing combined with 5-ALA application resulted in higher levels of chloroplast synthesis precursors and greater carbohydrate accumulation”
e0“This enhanced peroxide-scavenging capacity, maintained photosynthetic apparatus stability, improved ion homeostasis, and gave drill sowing stronger salt tolerance than broadcast sowing”
Claim · model-written summary
Drill sowing with 5-ALA improved ion homeostasis in rice seedlings under salt stress.
- Taxon
- riceOryza sativat0
- Treatment
- drill sowing combined with 5-ALA applicatione7
- Outcome
- ion homeostasise0
- Direction
- improvede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“rice seedlings under salt stress”
e7“Compared with broadcast sowing, drill sowing combined with 5-ALA application resulted in higher levels of chloroplast synthesis precursors and greater carbohydrate accumulation”
e0“This enhanced peroxide-scavenging capacity, maintained photosynthetic apparatus stability, improved ion homeostasis, and gave drill sowing stronger salt tolerance than broadcast sowing”
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See all 36 papers →8 of 11 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.