Abstract
Abstract Silicon (Si) uptake and deposition (silicification) in tissues is known to alleviate stresses and generally improve plant health. This is mostly studied in Si‐high accumulators, such as grasses, with comparatively less known about its effects on other plant functional groups, such as legumes. There is speculation that Si may positively impact the symbiosis between legumes and the nitrogen‐fixing bacteria (rhizobia) they associate with, but this is poorly understood. This study examined the effects of Si enrichment on legume species associated with rhizobia and the potential underlying mechanism of Si impacts. We conducted a glasshouse experiment with lucerne Medicago sativa and barrel medic M. truncatula associated with a model rhizobial strain. Six genotypes (three per species) were either supplemented with Si (+Si) or untreated (−Si). We quantified 16 functional traits which could be classified as plant growth, physiology, elemental chemistry, nodule activity and nitrogen fixation. The two legume species responded to Si distinctively. For example, Si supplementation increased shoot biomass by more than 10% in lucerne but growth was unaffected in barrel medic. Conversely, nitrogen‐fixing enzyme (nitrogenase) activity was promoted by more than 85% in +Si barrel medic plants but not in lucerne. Moreover, Si supplementation of lucerne increased the concentrations of Si in leaves by more than 36% but not in root nodules. Increased foliar concentrations of Si in lucerne were positively associated with increased shoot and root biomass in Sequel and Trifecta genotypes, respectively. Conversely, Si supplementation of barrel medic increased the concentration of Si in root nodules by 29% but not that in foliar tissues. Nitrogenase activity and where silicification occurred, differed between genotypes in barrel medic; nitrogenase activity was correlated with concentrations of Si in root nodules rather than that in foliar tissues in one genotype (Sephi) but the reverse was true in another (Hannaford). This study demonstrates that two closely related legume species can respond to Si in distinct ways, depending on plant genotype and symbiosis. These results present the overlooked function of Si in legume–rhizobia interactions, which could potentially enhance productivity of this important group of plants. A free Plain Language Summary can be found within the Supporting Information of this article.
Abstract from the paper’s OpenAlex record; open copy licensed public-domain. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 11
Claim · model-written summary
Silicon raised lucerne shoot biomass by more than 10%.
- Taxon
- lucerne
Medicago sativae0 - Treatment
- Si supplementatione0
- Outcome
- shoot biomasse0
- Direction
- increasede0
- Value
- more than 10%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Si supplementation increased shoot biomass by more than 10% in lucerne but growth was unaffected in barrel medic”
Claim · model-written summary
Silicon left barrel medic growth unaffected.
- Taxon
- barrel medic
Medicago truncatulae0 - Treatment
- Si supplementatione0
- Outcome
- growthe0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Si supplementation increased shoot biomass by more than 10% in lucerne but growth was unaffected in barrel medic”
Claim · model-written summary
Silicon promoted nitrogenase activity by more than 85% in barrel medic.
- Taxon
- barrel medicMedicago truncatulae0
- Treatment
- +Sie0
- Outcome
- nitrogen‐fixing enzyme (nitrogenase) activitye0
- Direction
- promotede0
- Value
- more than 85%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nitrogen‐fixing enzyme (nitrogenase) activity was promoted by more than 85% in +Si barrel medic plants but not in lucerne”
Claim · model-written summary
Silicon did not promote nitrogenase activity in lucerne.
- Taxon
- lucerneMedicago sativae0
- Treatment
- +Sie0
- Outcome
- nitrogen‐fixing enzyme (nitrogenase) activitye0
- Direction
- not in lucernee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nitrogen‐fixing enzyme (nitrogenase) activity was promoted by more than 85% in +Si barrel medic plants but not in lucerne”
Claim · model-written summary
Silicon raised lucerne leaf silicon concentrations by more than 36%.
- Taxon
- lucerneMedicago sativae0
- Treatment
- Si supplementatione0
- Outcome
- concentrations of Si in leavese0
- Direction
- increasede0
- Value
- more than 36%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Si supplementation of lucerne increased the concentrations of Si in leaves by more than 36% but not in root nodules”
Claim · model-written summary
Silicon did not raise lucerne root nodule silicon concentrations.
- Taxon
- lucerneMedicago sativae0
- Treatment
- Si supplementatione0
- Outcome
- root nodulese0
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Si supplementation of lucerne increased the concentrations of Si in leaves by more than 36% but not in root nodules”
Claim · model-written summary
Foliar silicon concentrations were positively associated with shoot biomass in Sequel lucerne.
- Taxon
- lucerneMedicago sativae0
- Material
- Sequele0
- Compound
- Sie0
- Outcome
- shoot and root biomasse0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased foliar concentrations of Si in lucerne were positively associated with increased shoot and root biomass in Sequel and Trifecta genotypes, respectively”
Claim · model-written summary
Foliar silicon concentrations were positively associated with root biomass in Trifecta lucerne.
- Taxon
- lucerneMedicago sativae0
- Material
- Trifectae0
- Compound
- Sie0
- Outcome
- root biomasse0
- Direction
- increasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increased foliar concentrations of Si in lucerne were positively associated with increased shoot and root biomass in Sequel and Trifecta genotypes, respectively”
Claim · model-written summary
Silicon increased barrel medic root nodule silicon concentration by 29%.
- Taxon
- barrel medicMedicago truncatulae0
- Treatment
- Si supplementatione0
- Outcome
- concentration of Si in root nodulese0
- Direction
- increasede0
- Value
- 29%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Si supplementation of barrel medic increased the concentration of Si in root nodules by 29% but not that in foliar tissues”
Claim · model-written summary
Silicon did not increase barrel medic foliar silicon concentration.
- Taxon
- barrel medicMedicago truncatulae0
- Treatment
- Si supplementatione0
- Outcome
- that in foliar tissuese0
- Direction
- note0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Si supplementation of barrel medic increased the concentration of Si in root nodules by 29% but not that in foliar tissues”
Claim · model-written summary
In Hannaford barrel medic, nitrogenase activity correlated with foliar silicon rather than root nodule silicon.
- Taxon
- barrel medicMedicago truncatulae0
- Material
- Hannaforde0
- Outcome
- nitrogenase activitye0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogenase activity and where silicification occurred, differed between genotypes in barrel medic; nitrogenase activity was correlated with concentrations of Si in root nodules rather than that in foliar tissues in one genotype (Sephi) but the reverse was true in another (Hannaford)”
The same questions in other papers
silicon atom · growth · Medicago sativa (alfalfa)Results differ
11 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- positive
9 papers more in this group
See all 13 papers →silicon atom · physiology: enzyme activity · Medicago sativa (alfalfa)Positive and negative results
2 in the opposite direction
- positive
- positive
silicon atom · symbiosis · Medicago sativa (alfalfa)Positive and negative results
3 in the opposite direction
- positive
- positive
- positive
silicon atom · nutrient: content · Medicago sativa (alfalfa)Positive and negative results
11 papers in the same direction as this paper · 1 in the opposite direction
- no effect
- positive
- positive
9 papers more in this group
See all 13 papers →silicon atom · growth · Medicago truncatula (barrel medic)Results agree
1 paper in the same direction as this paper
- no effect
silicon atom · symbiosis · Medicago truncatula (barrel medic)Results agree
2 papers in the same direction as this paper
- 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.