Abstract
Phytochelatins are enzymatically synthesized peptides involved in metal detoxification and have been measured in plants grown at very high Cd concentrations, but few studies have examined the response of plants at lower environmentally relevant Cd concentrations. Using an ethylenediaminetetraacetic acid (EDTA)-buffered nutrient medium, we have varied Cd exposure and measured phytochelatin and glutathione concentrations in romaine lettuce (Lactuca sativa L. var. longifolia Lam. var. Parris Island) grown in a flow-through hydroponic (FTH) system. Very low free ionic Cd (10(-9.6) M) increased average phytochelatin concentrations above those of controls, and increasing Cd resulted in increased phytochelatin production, though increases were tissue dependent. Glutathione concentrations also increased with increasing Cd. In other standard hydroponic experiments, the media were manipulated to vary total Cd concentration while the ionic Cd was fixed. We found that the total amount of Cd (primarily EDTA bound) in the medium altered thiol production in roots, whereas thiols in leaves remained constant. The Cd uptake into roots and translocation to old leaves was also influenced by the total concentration in the medium. Cadmium in all tissues was lower and in some tissues thiol concentrations were higher than in FTH-grown plants grown in identical medium, suggesting that nutrient delivery technique is also an important variable. Though phytochelatin and glutathione production can be sensitive to changes in bioavailable Cd, thiol concentrations will not necessarily reflect the Cd content of the plant tissues.
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Claims 9
Claim · model-written summary
Very low free ionic Cd increased average phytochelatin concentrations in romaine lettuce above those of controls.
- Taxon
- romaine lettuce
Lactuca sativa var. longifoliae0 - Treatment
- Very low free ionic Cd (10(-9.6) M)e1
- Outcome
- average phytochelatin concentrationse1
- Direction
- increasede1
- Comparator
- controlse1
- Setting
- flow-through hydroponic (FTH) systeme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in romaine lettuce (Lactuca sativa L. var. longifolia Lam. var. Parris Island) grown in a flow-through hydroponic (FTH) system”
e1“Very low free ionic Cd (10(-9.6) M) increased average phytochelatin concentrations above those of controls”
Claim · model-written summary
Increasing Cd increased phytochelatin production in lettuce, though the increase was tissue dependent.
- Taxon
- romaine lettuceLactuca sativa var. longifoliae0
- Treatment
- increasing Cde2
- Outcome
- phytochelatin productione2
- Direction
- increasede2
- Qualifier
- though increases were tissue dependente2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in romaine lettuce (Lactuca sativa L. var. longifolia Lam. var. Parris Island) grown in a flow-through hydroponic (FTH) system”
e2“increasing Cd resulted in increased phytochelatin production, though increases were tissue dependent”
Claim · model-written summary
Increasing Cd increased glutathione concentrations in romaine lettuce.
- Taxon
- romaine lettuceLactuca sativa var. longifoliae0
- Treatment
- increasing Cde3
- Outcome
- Glutathione concentrationse3
- Direction
- increasede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in romaine lettuce (Lactuca sativa L. var. longifolia Lam. var. Parris Island) grown in a flow-through hydroponic (FTH) system”
e3“Glutathione concentrations also increased with increasing Cd”
Claim · model-written summary
The total amount of Cd in the medium altered thiol production in lettuce roots.
- Taxon
- romaine lettuceLactuca sativa var. longifoliae0
- Treatment
- total amount of Cd (primarily EDTA bound) in the mediume4
- Outcome
- thiol production in rootse4
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in romaine lettuce (Lactuca sativa L. var. longifolia Lam. var. Parris Island) grown in a flow-through hydroponic (FTH) system”
e4“the total amount of Cd (primarily EDTA bound) in the medium altered thiol production in roots, whereas thiols in leaves remained constant”
Claim · model-written summary
The total amount of Cd in the medium did not change thiol concentrations in lettuce leaves.
- Taxon
- romaine lettuceLactuca sativa var. longifoliae0
- Treatment
- total amount of Cd (primarily EDTA bound) in the mediume4
- Outcome
- thiols in leavese4
- Direction
- no_changeinferrede4
- Qualifier
- remained constante4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in romaine lettuce (Lactuca sativa L. var. longifolia Lam. var. Parris Island) grown in a flow-through hydroponic (FTH) system”
e4“the total amount of Cd (primarily EDTA bound) in the medium altered thiol production in roots, whereas thiols in leaves remained constant”
Claim · model-written summary
The total Cd concentration in the medium influenced Cd uptake into roots and translocation to old leaves.
- Taxon
- romaine lettuceLactuca sativa var. longifoliae0
- Treatment
- total concentration in the mediume5
- Outcome
- The Cd uptake into roots and translocation to old leavese5
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in romaine lettuce (Lactuca sativa L. var. longifolia Lam. var. Parris Island) grown in a flow-through hydroponic (FTH) system”
e5“The Cd uptake into roots and translocation to old leaves was also influenced by the total concentration in the medium”
Claim · model-written summary
Cadmium in all tissues was lower in the nutrient delivery technique than in FTH-grown plants.
- Taxon
- romaine lettuceLactuca sativa var. longifoliae0
- Treatment
- nutrient delivery techniquee6
- Outcome
- Cadmium in all tissuese6
- Direction
- lowere6
- Comparator
- FTH-grown plantse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in romaine lettuce (Lactuca sativa L. var. longifolia Lam. var. Parris Island) grown in a flow-through hydroponic (FTH) system”
e6“Cadmium in all tissues was lower and in some tissues thiol concentrations were higher than in FTH-grown plants grown in identical medium, suggesting that nutrient delivery technique is also an important variable”
Claim · model-written summary
Thiol concentrations were higher in some tissues in the nutrient delivery technique than in FTH-grown plants.
- Taxon
- romaine lettuceLactuca sativa var. longifoliae0
- Treatment
- nutrient delivery techniquee6
- Outcome
- thiol concentrationse6
- Direction
- highere6
- Qualifier
- in some tissuese6
- Comparator
- FTH-grown plantse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in romaine lettuce (Lactuca sativa L. var. longifolia Lam. var. Parris Island) grown in a flow-through hydroponic (FTH) system”
e6“Cadmium in all tissues was lower and in some tissues thiol concentrations were higher than in FTH-grown plants grown in identical medium, suggesting that nutrient delivery technique is also an important variable”
Claim · model-written summary
Thiol concentrations in lettuce tissues do not necessarily reflect the Cd content of the plant tissues.
- Taxon
- romaine lettuceLactuca sativa var. longifoliae0
- Outcome
- thiol concentrations will not necessarily reflect the Cd content of the plant tissuese7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“in romaine lettuce (Lactuca sativa L. var. longifolia Lam. var. Parris Island) grown in a flow-through hydroponic (FTH) system”
e7“thiol concentrations will not necessarily reflect the Cd content of the plant tissues”
The same questions in other papers
ethylenediaminetetraacetic acid · molecular: metabolites · Lactuca sativa (garden lettuce)Positive and negative results
1 in the opposite direction
- positive
cadmium atom · molecular: metabolites · Lactuca sativa (garden lettuce)Positive and negative results
5 papers in the same direction as this paper · 1 in the opposite direction
- positive
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3 papers more in this group
See all 7 papers →in vitro · molecular: metabolites · Lactuca sativa (garden lettuce)Positive 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.