Abstract
Cadmium (Cd) is a phytotoxic heavy metal that causes rapid growth reduction. To investigate if Cd interferes with the metabolism of auxin, a major growth hormone in plants, poplars (Populus × canescens) expressing a heterologous GH3::GUS reporter gene were exposed to 50 μM Cd in hydroponic solutions. Growth, photosynthetic performance, lignification, peroxidase activity, auxin concentration, and GUS staining were determined in order to record the activities of GH3 enzymes in the stem apex, the elongation zone, wood in the zone of radial growth, and in roots. Cd-induced growth reductions were tissue-specific decreasing in the order: roots>wood>shoot elongation and leaf initiation, whereas Cd concentrations increased in the order: leaves<wood<roots. Cd almost abolished the GH3 signal in the stem apex but caused strong increases in the vascular system of roots as well as in parenchymatic cells in the xylem. These changes were accompanied by increases in lignin and peroxidase activities and decreases in auxin concentrations. Since GH3 enzymes remove auxin from the active pool by conjugation and act as mediators between growth and defence, our data suggest that Cd stress triggered increases in GH3 activities which, in turn, depleted auxin in wood and thereby shunted the metabolism to enhanced formation of lignin.
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Claims 8
Claim · model-written summary
Cadmium reduced poplar growth most in roots, followed by wood, shoot elongation and leaf initiation.
- Organ / stage
- roots>wood>shoot elongation and leaf initiatione0
- Treatment
- Cde0
- Outcome
- growth reductionse0
- Direction
- reductionse0
PopulusNot reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cd-induced growth reductions were tissue-specific decreasing in the order: roots>wood>shoot elongation and leaf initiation”
t0“poplar”
Claim · model-written summary
Cadmium concentration was highest in roots, then wood, then leaves.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cd concentrations increased in the order: leaves<wood<roots”
t0“poplar”
Claim · model-written summary
Cadmium nearly abolished GH3 signal in the stem apex.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cd almost abolished the GH3 signal in the stem apex”
t0“poplar”
Claim · model-written summary
Cadmium increased GH3 signal in the root vascular system and xylem parenchyma.
- Organ / stage
- vascular system of roots as well as in parenchymatic cells in the xyleme0
- Treatment
- Cde1
- Gene
- GH3e1
- Outcome
- GH3 signale1
- Direction
- increasese0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“caused strong increases in the vascular system of roots as well as in parenchymatic cells in the xylem”
e1“Cd almost abolished the GH3 signal in the stem apex”
t0“poplar”
Claim · model-written summary
Cadmium-associated changes included increased lignin.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These changes were accompanied by increases in lignin and peroxidase activities and decreases in auxin concentrations.”
t0“poplar”
Claim · model-written summary
Cadmium-associated changes included increased peroxidase activity.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increases in lignin and peroxidase activities”
t0“poplar”
Claim · model-written summary
Cadmium-associated changes included decreased auxin concentration.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“decreases in auxin concentrations”
t0“poplar”
Claim · model-written summary
Authors propose that cadmium activates GH3, depleting auxin and promoting lignin formation in wood.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cd stress triggered increases in GH3 activities which, in turn, depleted auxin in wood and thereby shunted the metabolism to enhanced formation of lignin”
t0“poplar”
The same questions in other papers
cadmium atom · growth · Populus (poplar)Results differ
8 papers in the same direction as this paper · 2 in the opposite direction
- positive
- positive
- negative
7 papers more in this group
See all 11 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.