Abstract
Establishment, growth, and persistence of forage legumes on shallow, infertile, and acidic hill-land pasture soils, often because of the expense of optimal liming and fertilization, remains a problem. A better understanding of the mechanism of inhibition of symbiosis establishment in these soils, and its alleviation by minimal liming, could aid in the solution of this problem. White clover (Trifolium repens L.) seedlings were planted in two model systems (deepots or plates), utilizing an air-dried, nonsterile Ultisol limed from pHw 4.71 (nil lime) to 4.99, and inoculated with effective rhizobia (Rhizobium leguminosarum bv. trifolii). Both model systems demonstrated the stimulatory effect of low-level liming (soil pH increase) on nodulation 14 days after planting (DAP) and before differences in shoot mass responses were apparent. Examination of roots grown in soil plates (∼1/5 volume of deepots) at 3, 6, 8, 10, 12 and 14 DAP revealed a significant (r = 0.90;P ≤ 0.05) nodulation response to soil pH, but only at 14 DAP. However, the consistent pattern of nodulation responses to soil pH, almost throughout the entire growth period, suggests that nodulation was being stimulated by low-level liming as early as 6 to 8 DAP. With the exception of small differences toward the end of the experiment (12–14 DAP), root development (total length, diameter, volume, surface area, tip, and fork number) was unaffected by soil pH. Root length, sorted into eight diameter classes, was similarly unresponsive to soil pH. Collectively, these results suggest that inhibition of symbiosis establishment in our soil plate model system occurs at the cellular (root hair and/or nodule primordium) level, rather than at the tissue (root) level. From a practical (field) perspective, our finding that the rhizobial level interacted with soil pH on nodulation intensity suggests that the development of either a more acidic soil-tolerant plant cultivar or rhizobial strain would lead to a more rapid and robust symbiosis in infertile, acidic soils.
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Claims 7
Claim · model-written summary
Low-level liming (soil pH increase) stimulated white clover nodulation 14 days after planting, before shoot mass differences appeared, relative to unlimed soil.
- Taxon
- WHITE CLOVER
Trifolium repenst0 - Treatment
- low-level liminge0
- Interactor
- Rhizobium leguminosarum bv. trifoliiRhizobium leguminosarum bv. trifoliie2symbiont
- Outcome
- nodulatione0
- Direction
- stimulatorye0
- Qualifier
- 14 days after plantinge0
- Comparator
- nil limee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Both model systems demonstrated the stimulatory effect of low-level liming (soil pH increase) on nodulation 14 days after planting (DAP)”
e1“limed from pHw 4.71 (nil lime) to 4.99”
e2“inoculated with effective rhizobia (Rhizobium leguminosarum bv. trifolii)”
t0“WHITE CLOVER”
Claim · model-written summary
In soil plates, nodulation correlated significantly with soil pH (r = 0.90, P <= 0.05), but only at 14 DAP.
- Taxon
- WHITE CLOVERTrifolium repenst0
- Treatment
- soil pHe3
- Outcome
- nodulation responsee3
- Direction
- increaseinferrede3
- Value
- r = 0.90e3
- Qualifier
- only at 14 DAPe3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“a significant (r = 0.90;P ≤ 0.05) nodulation response to soil pH, but only at 14 DAP”
t0“WHITE CLOVER”
Claim · model-written summary
Root development (total length, diameter, volume, surface area, tip and fork number) was unaffected by soil pH except for small differences at 12-14 DAP.
- Taxon
- WHITE CLOVERTrifolium repenst0
- Treatment
- soil pHe4
- Outcome
- root developmente4
- Direction
- unaffectede4
- Qualifier
- small differences toward the end of the experiment (12–14 DAP)e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“With the exception of small differences toward the end of the experiment (12–14 DAP), root development (total length, diameter, volume, surface area, tip, and fork number) was unaffected by soil pH”
t0“WHITE CLOVER”
Claim · model-written summary
Root length sorted into eight diameter classes was similarly unresponsive to soil pH.
- Taxon
- WHITE CLOVERTrifolium repenst0
- Treatment
- soil pHe5
- Outcome
- Root lengthe5
- Direction
- unresponsivee5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“Root length, sorted into eight diameter classes, was similarly unresponsive to soil pH”
t0“WHITE CLOVER”
Claim · model-written summary
Rhizobial level interacted with soil pH on nodulation intensity.
- Taxon
- WHITE CLOVERTrifolium repenst0
- Treatment
- soil pHe6
- Interactor
- rhizobiale6symbiont
- Outcome
- nodulation intensitye6
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“the rhizobial level interacted with soil pH on nodulation intensity”
t0“WHITE CLOVER”
Claim · model-written summary
The authors suggest inhibition of symbiosis establishment in the soil plate model occurs at the cellular (root hair and/or nodule primordium) level rather than the root tissue level.
- Taxon
- WHITE CLOVERTrifolium repenst0
- Outcome
- inhibition of symbiosis establishmente7
- Qualifier
- cellular (root hair and/or nodule primordium) levele7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“inhibition of symbiosis establishment in our soil plate model system occurs at the cellular (root hair and/or nodule primordium) level, rather than at the tissue (root) level”
t0“WHITE CLOVER”
Claim · model-written summary
The authors propose that a more acidic soil-tolerant plant cultivar or rhizobial strain would lead to a more rapid and robust symbiosis in infertile, acidic soils.
- Taxon
- WHITE CLOVERTrifolium repenst0
- Outcome
- more rapid and robust symbiosise0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“development of either a more acidic soil-tolerant plant cultivar or rhizobial strain would lead to a more rapid and robust symbiosis in infertile, acidic soils”
t0“WHITE CLOVER”
The same questions in other papers
ph · growth · Trifolium repens (white clover)Results agree
4 papers in the same direction as this paper
- negative
- negative
- negative
1 paper more in this group
See all 5 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.