Abstract
From a study of the effects of Ca ions on the nodulation of subterranean clover in flowing culture solutions it is concluded that root infection or nodule initiation has a higher Ca requirement than either nodule development or host plant growth in the presence of fixed nitrogen.Increasing Ca concentration from 246 to 720 mum had no effect on growth of the host plant but increased the number of nodules from 7 to 24 per plant. Decreasing Ca concentration from 246 to 4 mum progressively decreased both plant growth and nodule numbers.It is suggested that nodule infection or initiation required higher solution concentration of Ca than nodule development since transferring plants after 10 days in lower Ca treatments to 720 mum Ca for 7 days did not increase nodule numbers above those on plants treated continuously at low Ca. Similarly transferring plants from 720 mum Ca to lower Ca treatments did not decrease nodule numbers much below those on plants grown continuously at 720 mum Ca even though growth was depressed. Once initiated, nodule development proceeded at concentrations of Ca too low for plant growth.The high Ca requirement for root infection or nodule initiation was not thought to be due to effects on survival or growth of Rhizobium and could not be related to effects of Ca on a number of relevant processes:-tap root length, root hair development, or lateral root initiation.
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Claims 8
Claim · model-written summary
Increasing Ca from 246 to 720 mum did not affect host growth.
- Taxon
- Subterranean Clover
Trifolium subterraneumt0 - Treatment
- Increasing Ca concentration from 246 to 720 mume0
- Outcome
- growth of the host plante0
- Direction
- no effecte0
- Comparator
- 246e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing Ca concentration from 246 to 720 mum had no effect on growth of the host plant”
t0“Subterranean Clover (Trifolium subterraneum L.)”
Claim · model-written summary
Increasing Ca from 246 to 720 mum increased nodules from 7 to 24 per plant.
- Taxon
- Subterranean CloverTrifolium subterraneumt0
- Treatment
- Increasing Ca concentration from 246 to 720 mume1
- Outcome
- number of nodulese0
- Direction
- increasede0
- Value
- 24 per plante0
- Comparator
- 246e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased the number of nodules from 7 to 24 per plant”
e1“Increasing Ca concentration from 246 to 720 mum had no effect on growth of the host plant”
t0“Subterranean Clover (Trifolium subterraneum L.)”
Claim · model-written summary
Reducing Ca from 246 to 4 mum progressively reduced plant growth.
- Taxon
- Subterranean CloverTrifolium subterraneumt0
- Treatment
- Decreasing Ca concentration from 246 to 4 mume0
- Outcome
- plant growthe0
- Direction
- decreasede0
- Comparator
- 246e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Decreasing Ca concentration from 246 to 4 mum progressively decreased both plant growth and nodule numbers”
t0“Subterranean Clover (Trifolium subterraneum L.)”
Claim · model-written summary
Reducing Ca from 246 to 4 mum progressively reduced nodule numbers.
- Taxon
- Subterranean CloverTrifolium subterraneumt0
- Treatment
- Decreasing Ca concentration from 246 to 4 mume0
- Outcome
- nodule numberse0
- Direction
- decreasede0
- Comparator
- 246e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Decreasing Ca concentration from 246 to 4 mum progressively decreased both plant growth and nodule numbers”
t0“Subterranean Clover (Trifolium subterraneum L.)”
Claim · model-written summary
Late transfer from low to 720 mum Ca did not increase nodule numbers over continuous low Ca.
- Taxon
- Subterranean CloverTrifolium subterraneumt0
- Treatment
- transferring plants after 10 days in lower Ca treatments to 720 mum Ca for 7 dayse0
- Outcome
- nodule numberse0
- Direction
- did not increasee0
- Comparator
- plants treated continuously at low Cae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transferring plants after 10 days in lower Ca treatments to 720 mum Ca for 7 days did not increase nodule numbers above those on plants treated continuously at low Ca”
t0“Subterranean Clover (Trifolium subterraneum L.)”
Claim · model-written summary
Transfer from 720 mum to lower Ca did not greatly decrease nodule numbers versus continuous high Ca.
- Taxon
- Subterranean CloverTrifolium subterraneumt0
- Treatment
- transferring plants from 720 mum Ca to lower Ca treatmentse0
- Outcome
- nodule numberse0
- Direction
- did not decreasee0
- Comparator
- plants grown continuously at 720 mum Cae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“transferring plants from 720 mum Ca to lower Ca treatments did not decrease nodule numbers much below those on plants grown continuously at 720 mum Ca”
t0“Subterranean Clover (Trifolium subterraneum L.)”
Claim · model-written summary
Transfer from high to lower Ca depressed growth.
- Taxon
- Subterranean CloverTrifolium subterraneumt0
- Treatment
- lower Ca treatmentse1
- Outcome
- growthe0
- Direction
- depressede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“even though growth was depressed”
e1“transferring plants from 720 mum Ca to lower Ca treatments”
t0“Subterranean Clover (Trifolium subterraneum L.)”
Claim · model-written summary
Nodule development proceeded at Ca concentrations too low for plant growth.
- Taxon
- Subterranean CloverTrifolium subterraneumt0
- Outcome
- nodule development proceedede0
- Qualifier
- concentrations of Ca too low for plant growthe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Once initiated, nodule development proceeded at concentrations of Ca too low for plant growth.”
t0“Subterranean Clover (Trifolium subterraneum L.)”
The same questions in other papers
calcium atom · symbiosis · Trifolium subterraneumPositive and negative results
2 in the opposite direction
- no effect
- no effect
calcium atom · growth · Trifolium subterraneumPositive and negative results
3 in the opposite direction
- positive
- positive
- positive
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.