Abstract
Abstract Toxicity of metals to plants and microbes depends on the chemical activities of metals in the soil solution. To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii , the infection process, and nodulation, a growth chamber study was conducted. The chelator EGTA [ethylenebis(oxyethylenetrinitrilo) tetraacetate] was used to buffer Zn 2+ and Cd 2+ activities in nutrient solution from pZn 2+ = 8.0 to 5.0 and pCd 2+ = 10.5 to 8.0 mol L −1 . Plants grown in pZn 2+ = 5.0 and pCd 2+ = 8.75 and 8.65 were stunted and chlorotic with interveinal necrosis. Shoot concentrations of Zn and Cd averaged >200 and 40 mg kg −1 , respectively, in these treatments. This resulted in a 60% yield reduction for plants grown in pZn 2+ = 5.0. In pCd 2+ = 8.75 and 8.65, 40 and 60% yield reductions, respectively, were observed. In treatments where mineral N was supplied to plants, 20 to 35% greater shoot yield was recorded compared with plants inoculated with rhizobia, presumably due to a period of starvation for N due to the delay in the onset of fixation. Nodulation was observed at all Zn 2+ and Cd 2+ activities. At pCd 2+ = 8.75 and 8.65, however, there was a delay in nodulation. Most nodules were effective in N 2 fixation irrespective of Zn 2+ and Cd 2+ activity. Enumeration of viable cells showed a significant decline of total cell counts from 10 5.5 cells mL −1 in the control to 10 5.0 and 10 4.5 cells mL −1 at the highest Zn 2+ and Cd 2+ activities, respectively. At the activities studied, Cd was more toxic to rhizobia and nodulation than Zn. At the highest Cd 2+ activity, however, plants were killed within 48 h due to metal toxicity. This technique showed for the first time that toxicity of Zn and Cd was greater to plants than to rhizobia.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. 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 15
Claim · model-written summary
Plants at pZn 2+ = 5.0 and pCd 2+ = 8.75 and 8.65 were stunted and chlorotic with interveinal necrosis
- Taxon
- white clover
Trifolium repense1 - Treatment
- pZn 2+ = 5.0 and pCd 2+ = 8.75 and 8.65e2
- Interactor
- Rhizobium leguminosarum bv. trifoliiRhizobium leguminosarum bv. trifoliie1symbiont
- Outcome
- stunted and chlorotic with interveinal necrosise2
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e2“Plants grown in pZn 2+ = 5.0 and pCd 2+ = 8.75 and 8.65 were stunted and chlorotic with interveinal necrosis”
Claim · model-written summary
Shoot concentration of Zn exceeded 200 in the highest Zn treatments
- Taxon
- white cloverTrifolium repense1
- Outcome
- Shoot concentrations of Zne3
- Value
- >200e3
- Qualifier
- in these treatmentse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e3“Shoot concentrations of Zn and Cd averaged >200 and 40 mg kg −1 , respectively, in these treatments”
Claim · model-written summary
Shoot concentration of Cd was 40 mg kg −1 in the highest Cd treatments
- Taxon
- white cloverTrifolium repense1
- Outcome
- Shoot concentrations of Zn and Cde3
- Value
- 40 mg kg −1e3
- Qualifier
- respectively, in these treatmentse3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e3“Shoot concentrations of Zn and Cd averaged >200 and 40 mg kg −1 , respectively, in these treatments”
Claim · model-written summary
Zn activity pZn 2+ = 5.0 reduced white clover yield by 60%
- Taxon
- white cloverTrifolium repense1
- Treatment
- pZn 2+ = 5.0e4
- Outcome
- yielde4
- Direction
- reductione4
- Value
- 60%e4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e4“This resulted in a 60% yield reduction for plants grown in pZn 2+ = 5.0”
Claim · model-written summary
Cd activity pCd 2+ = 8.75 reduced white clover yield by 40
- Taxon
- white cloverTrifolium repense1
- Treatment
- pCd 2+ = 8.75e5
- Outcome
- yielde5
- Direction
- reductionse5
- Value
- 40e5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e5“In pCd 2+ = 8.75 and 8.65, 40 and 60% yield reductions, respectively, were observed”
Claim · model-written summary
Cd activity pCd 2+ = 8.65 reduced white clover yield by 60%
- Taxon
- white cloverTrifolium repense1
- Treatment
- pCd 2+ = 8.75 and 8.65e5
- Outcome
- yielde5
- Direction
- reductionse5
- Value
- 60%e5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e5“In pCd 2+ = 8.75 and 8.65, 40 and 60% yield reductions, respectively, were observed”
Claim · model-written summary
Mineral N supply gave 20 to 35% greater white clover shoot yield than rhizobia-inoculated plants
- Taxon
- white cloverTrifolium repense1
- Treatment
- mineral Ne6
- Interactor
- rhizobiae6symbiont
- Outcome
- shoot yielde6
- Direction
- greatere6
- Value
- 20 to 35%e6
- Comparator
- plants inoculated with rhizobiae6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e6“In treatments where mineral N was supplied to plants, 20 to 35% greater shoot yield was recorded compared with plants inoculated with rhizobia”
Claim · model-written summary
Nodulation of white clover was observed at all Zn and Cd activities tested
- Taxon
- white cloverTrifolium repense1
- Treatment
- Zn 2+ and Cd 2+ activitiese7
- Interactor
- Rhizobium leguminosarum bv. trifoliiRhizobium leguminosarum bv. trifoliie1symbiont
- Outcome
- Nodulatione7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e7“Nodulation was observed at all Zn 2+ and Cd 2+ activities”
Claim · model-written summary
The highest Cd activity at pCd 2+ = 8.75 and 8.65 delayed nodulation of white clover
- Taxon
- white cloverTrifolium repense1
- Treatment
- pCd 2+ = 8.75 and 8.65e2
- Interactor
- Rhizobium leguminosarum bv. trifoliiRhizobium leguminosarum bv. trifoliie1symbiont
- Outcome
- nodulatione2
- Direction
- delaye2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e2“At pCd 2+ = 8.75 and 8.65, however, there was a delay in nodulation”
Claim · model-written summary
Most white clover nodules were effective in N 2 fixation irrespective of Zn and Cd activity
- Taxon
- white cloverTrifolium repense1
- Treatment
- Zn 2+ and Cd 2+ activitye2
- Interactor
- Rhizobium leguminosarum bv. trifoliiRhizobium leguminosarum bv. trifoliie1symbiont
- Outcome
- effective in N 2 fixatione2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e2“Most nodules were effective in N 2 fixation irrespective of Zn 2+ and Cd 2+ activity”
Claim · model-written summary
Zn activity at the highest level reduced total rhizobial cell counts to 10 5.0 cells per mL compared with the control
- Taxon
- white cloverTrifolium repense1
- Treatment
- highest Zn 2+ and Cd 2+ activitiese2
- Interactor
- Rhizobium leguminosarum bv. trifoliiRhizobium leguminosarum bv. trifoliie1symbiont
- Outcome
- total cell countse2
- Direction
- declinee2
- Value
- 10 5.0e2
- Qualifier
- respectivelye2
- Comparator
- the controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e2“Enumeration of viable cells showed a significant decline of total cell counts from 10 5.5 cells mL −1 in the control to 10 5.0 and 10 4.5 cells mL −1 at the highest Zn 2+ and Cd 2+ activities, respectively”
Claim · model-written summary
Cd activity at the highest level reduced total rhizobial cell counts to 10 4.5 cells per mL compared with the control
- Taxon
- white cloverTrifolium repense1
- Treatment
- highest Zn 2+ and Cd 2+ activitiese2
- Interactor
- Rhizobium leguminosarum bv. trifoliiRhizobium leguminosarum bv. trifoliie1symbiont
- Outcome
- total cell countse2
- Direction
- declinee2
- Value
- 10 4.5e2
- Qualifier
- respectivelye2
- Comparator
- the controle2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e2“Enumeration of viable cells showed a significant decline of total cell counts from 10 5.5 cells mL −1 in the control to 10 5.0 and 10 4.5 cells mL −1 at the highest Zn 2+ and Cd 2+ activities, respectively”
Claim · model-written summary
Cd was more toxic than Zn to rhizobia and nodulation of white clover
- Taxon
- white cloverTrifolium repense1
- Treatment
- Cde2
- Interactor
- rhizobiae2symbiont
- Outcome
- toxic to rhizobia and nodulatione2
- Direction
- more toxice2
- Comparator
- Zne2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e2“At the activities studied, Cd was more toxic to rhizobia and nodulation than Zn”
Claim · model-written summary
The highest Cd activity killed white clover plants within 48 h
- Taxon
- white cloverTrifolium repense1
- Treatment
- highest Cd 2+ activitye2
- Outcome
- plants were killede2
- Qualifier
- within 48 he2
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e2“At the highest Cd 2+ activity, however, plants were killed within 48 h due to metal toxicity”
Claim · model-written summary
Toxicity of Zn and Cd was greater to white clover plants than to rhizobia
- Taxon
- white cloverTrifolium repense1
- Treatment
- Zn and Cde2
- Interactor
- rhizobiae2symbiont
- Outcome
- toxicitye2
- Direction
- greatere2
- Comparator
- rhizobiae2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“To examine the effects of Zn 2+ and Cd 2+ activities on white clover ( Trifolim repens L.), Rhizobium leguminosarum bv. trifolii”
e2“This technique showed for the first time that toxicity of Zn and Cd was greater to plants than to rhizobia”
The same questions in other papers
cadmium atom · symbiosis · Trifolium repens (white clover)Results agree
1 paper in the same direction as this paper
- no effect
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.