Abstract
In salt marsh soils, germination and the first phases of seedling development often occur under dark, hypoxic or anoxic, and saline conditions. Spartina alterniflora and Phragmites australis seedling development were examined under covaried oxygen and salinity concentrations in growth chamber experiments. First, the effects of oxygen and salinity on seedling development were tested in the dark, using a 5 5 factorial design. Oxygen did not affect P. australis plumule growth at oxygen concentrations from 21 down to 2.5%. Plumules were longer at ≤10 than at ≥25 g NaCl/L. Root growth was maximum in 21% oxygen, at ≤10 g NaCl/L and reduced at all salinities in oxygen concentrations ≤10%. No plumule or root growth occurred under anoxia. Salinity did not affect S. alterniflora mesocotyl emergence, which was fastest in anoxia and hypoxia. Mesocotyls did not emerge from the spikelet in 21% oxygen. In contrast, plumule growth was fastest in 21% oxygen, but was inhibited in anoxia. Under low oxygen and high salinity both plumule and root elongation were reduced. Coleoptile and mesocotyl elongation were greatest in 2.5 and 5% oxygen, and shortest in anoxia. The percentage of mesocotyls elongating was also highest in 2.5% oxygen. Rapid S. alterniflora coleoptile and mesocotyl elongation in anoxia enables its seedlings to escape the impact of the stressful environment where its seeds can germinate, but the seedlings could not survive otherwise. In separate experiments, S. alterniflora seeds were germinated and the seedlings grown in the dark for 10 d, then exposed to light for 4 d. Prior to illumination the seedlings did not develop beyond the stage of a small plumule enclosed in the coleoptile. Within 48 h of illumination in the presence of CO2, roots emerged and the plumule elongated inside the coleoptile at salinities up to 40 g NaCl/L, while the external environment remained anoxic. Without CO2, plumule growth and root development did not occur. This suggested oxygen was produced inside the coleoptile by the photosynthesizing plumule, and triggered root development. The ability of S. alterniflora seedlings to continue development under external anoxia and high salinity gives that species a competitive advantage over P. australis in high salinity and/or poorly drained marshes.
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Claims 18
Claim · model-written summary
Oxygen from 21 down to 2.5% did not affect P. australis plumule growth.
- Taxon
- P. australis
Phragmites australise0 - Treatment
- oxygen concentrations from 21 down to 2.5%e0
- Outcome
- plumule growthe0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Oxygen did not affect P. australis plumule growth at oxygen concentrations from 21 down to 2.5%”
Claim · model-written summary
P. australis plumules were longer at 10 g NaCl/L or less than at 25 g NaCl/L or more.
- Taxon
- P. australisPhragmites australise0
- Treatment
- ≤10 than at ≥25 g NaCl/Le1
- Outcome
- Plumulese1
- Direction
- longere1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P. australis plumule growth”
e1“Plumules were longer at ≤10 than at ≥25 g NaCl/L”
Claim · model-written summary
P. australis root growth was maximum at 21% oxygen and at 10 g NaCl/L or less.
- Taxon
- P. australisPhragmites australise0
- Treatment
- 21% oxygen, at ≤10 g NaCl/Le1
- Outcome
- Root growthe1
- Direction
- maximume1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P. australis plumule growth”
e1“Root growth was maximum in 21% oxygen, at ≤10 g NaCl/L and reduced at all salinities in oxygen concentrations ≤10%”
Claim · model-written summary
P. australis root growth was reduced at all salinities in oxygen concentrations of 10% or less.
- Taxon
- P. australisPhragmites australise0
- Treatment
- oxygen concentrations ≤10%e1
- Outcome
- Root growthe1
- Direction
- reducede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P. australis plumule growth”
e1“Root growth was maximum in 21% oxygen, at ≤10 g NaCl/L and reduced at all salinities in oxygen concentrations ≤10%”
Claim · model-written summary
No P. australis plumule or root growth occurred under anoxia.
- Taxon
- P. australisPhragmites australise0
- Treatment
- anoxiae1
- Outcome
- plumule or root growthe1
- Direction
- decreaseinferrede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“P. australis plumule growth”
e1“No plumule or root growth occurred under anoxia”
Claim · model-written summary
Salinity did not affect S. alterniflora mesocotyl emergence.
- Taxon
- S. alterniflora
Sporobolus alternifloruse0 - Treatment
- Salinitye0
- Outcome
- mesocotyl emergencee0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salinity did not affect S. alterniflora mesocotyl emergence”
Claim · model-written summary
S. alterniflora mesocotyl emergence was fastest in anoxia and hypoxia.
- Taxon
- S. alternifloraSporobolus alternifloruse0
- Treatment
- anoxia and hypoxiae0
- Outcome
- mesocotyl emergencee0
- Direction
- fasteste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salinity did not affect S. alterniflora mesocotyl emergence, which was fastest in anoxia and hypoxia”
Claim · model-written summary
S. alterniflora mesocotyls did not emerge from the spikelet in 21% oxygen.
- Taxon
- S. alternifloraSporobolus alternifloruse0
- Treatment
- 21% oxygene1
- Outcome
- did not emerge from the spikelete1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salinity did not affect S. alterniflora mesocotyl emergence”
e1“Mesocotyls did not emerge from the spikelet in 21% oxygen”
Claim · model-written summary
S. alterniflora plumule growth was fastest in 21% oxygen.
- Taxon
- S. alternifloraSporobolus alternifloruse0
- Treatment
- 21% oxygene1
- Outcome
- plumule growthe1
- Direction
- fasteste1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salinity did not affect S. alterniflora mesocotyl emergence”
e1“plumule growth was fastest in 21% oxygen”
Claim · model-written summary
S. alterniflora plumule growth was inhibited in anoxia.
- Taxon
- S. alternifloraSporobolus alternifloruse0
- Treatment
- anoxiae1
- Outcome
- plumule growthe1
- Direction
- inhibitede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Salinity did not affect S. alterniflora mesocotyl emergence”
e1“plumule growth was fastest in 21% oxygen, but was inhibited in anoxia”
Claim · model-written summary
Under low oxygen and high salinity both plumule and root elongation were reduced.
Not reportedTaxonComparator
Verbatim
e0“Under low oxygen and high salinity both plumule and root elongation were reduced”
Claim · model-written summary
Coleoptile and mesocotyl elongation were greatest in 2.5 and 5% oxygen and shortest in anoxia.
- Treatment
- 2.5 and 5% oxygene0
- Outcome
- Coleoptile and mesocotyl elongatione0
- Direction
- greateste0
- Comparator
- anoxiae0
Not reportedTaxon
Verbatim
e0“Coleoptile and mesocotyl elongation were greatest in 2.5 and 5% oxygen, and shortest in anoxia”
Claim · model-written summary
The percentage of mesocotyls elongating was highest in 2.5% oxygen.
Not reportedTaxonComparator
Verbatim
e0“The percentage of mesocotyls elongating was also highest in 2.5% oxygen”
Claim · model-written summary
Rapid S. alterniflora coleoptile and mesocotyl elongation in anoxia is interpreted to enable seedlings to escape the stressful environment where seeds germinate.
- Taxon
- S. alternifloraSporobolus alternifloruse0
- Treatment
- anoxiae0
- Outcome
- escape the impact of the stressful environmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rapid S. alterniflora coleoptile and mesocotyl elongation in anoxia enables its seedlings to escape the impact of the stressful environment where its seeds can germinate”
Claim · model-written summary
With CO2 and illumination, S. alterniflora seedlings grown in dark for 10 d developed roots and plumule elongation inside the coleoptile at salinities up to 40 g NaCl/L while the external environment stayed anoxic.
- Taxon
- S. alternifloraSporobolus alternifloruse0
- Treatment
- illumination in the presence of CO2e1
- Outcome
- roots emerged and the plumule elongatede1
- Qualifier
- salinities up to 40 g NaCl/Le1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“S. alterniflora seeds”
e1“Within 48 h of illumination in the presence of CO2, roots emerged and the plumule elongated inside the coleoptile at salinities up to 40 g NaCl/L, while the external environment remained anoxic”
Claim · model-written summary
Without CO2, S. alterniflora plumule growth and root development did not occur.
- Taxon
- S. alternifloraSporobolus alternifloruse0
- Treatment
- Without CO2e1
- Outcome
- plumule growth and root developmente1
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“S. alterniflora seeds”
e1“Without CO2, plumule growth and root development did not occur”
Claim · model-written summary
The authors suggest oxygen was produced inside the coleoptile by the photosynthesizing plumule and triggered root development in S. alterniflora.
- Taxon
- S. alternifloraSporobolus alternifloruse0
- Compound
- oxygene1
- Outcome
- root developmente1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“S. alterniflora seeds”
e1“This suggested oxygen was produced inside the coleoptile by the photosynthesizing plumule, and triggered root development”
Claim · model-written summary
The ability of S. alterniflora seedlings to continue development under external anoxia and high salinity gives it a competitive advantage over P. australis in high salinity and/or poorly drained marshes.
- Taxon
- S. alternifloraSporobolus alternifloruse0
- Interactor
- P. australisPhragmites australise0other
- Outcome
- competitive advantage over P. australise0
- Qualifier
- high salinity and/or poorly drained marshese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The ability of S. alterniflora seedlings to continue development under external anoxia and high salinity gives that species a competitive advantage over P. australis in high salinity and/or poorly drained marshes”
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See all 9 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.