Abstract
Hormesis, which describes the stimulatory effect of low doses of toxic substances on growth, is a well-known phenomenon in the plant and animal kingdoms. However, the mechanisms that are involved in this phenomenon are still poorly understood. We performed preliminary studies on corn coleoptile sections, which showed a positive correlation between the stimulation of growth by Cd or Pb and an increase in the auxin and H2O2 content in the coleoptile sections. Subsequently, we grew corn seedlings in hydroponic culture and tested a wide range of Cd or Pb concentrations in order to determine hormetic growth stimulation. In these seedlings the gas exchange and the chlorophyll a fluorescence, as well as the content of chlorophyll, flavonol, auxin and hydrogen peroxide, were measured. We found that during the hormetic stimulation of growth, the response of the photosynthetic apparatus to Cd and Pb differed significantly. While the application of Cd mostly caused a decrease in various photosynthetic parameters, the application of Pb stimulated some of them. Nevertheless, we discovered that the common features of the hormetic stimulation of shoot growth by heavy metals are an increase in the auxin and flavonol content and the maintenance of hydrogen peroxide at the same level as the control plants.
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Claims 6
Claim · model-written summary
In corn coleoptile sections, growth stimulation by Cd or Pb correlated positively with increased auxin and H2O2 content.
- Taxon
- corn
Zea mays subsp. mayse1 - Organ / stage
- coleoptile sectionse1
- Treatment
- Cd or Pbe1
- Outcome
- auxin and H2O2 contente1
- Direction
- increasee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“corn coleoptile sections, which showed a positive correlation between the stimulation of growth by Cd or Pb and an increase in the auxin and H2O2 content in the coleoptile sections”
Claim · model-written summary
Cd application mostly decreased various photosynthetic parameters in corn seedlings.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- Cde2
- Outcome
- photosynthetic parameterse2
- Direction
- decreasee2
- Qualifier
- mostlye2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“While the application of Cd mostly caused a decrease in various photosynthetic parameters, the application of Pb stimulated some of them”
t0“in Corn Treated with Cd or Pb”
Claim · model-written summary
Pb application stimulated some photosynthetic parameters in corn seedlings.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- Pbe2
- Outcome
- photosynthetic parameterse2
- Direction
- stimulatede2
- Qualifier
- some of theme2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“While the application of Cd mostly caused a decrease in various photosynthetic parameters, the application of Pb stimulated some of them”
t0“in Corn Treated with Cd or Pb”
Claim · model-written summary
The response of the photosynthetic apparatus to Cd and Pb in corn differed significantly during hormetic growth stimulation.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- Cd and Pbe3
- Outcome
- response of the photosynthetic apparatuse3
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“the response of the photosynthetic apparatus to Cd and Pb differed significantly”
t0“in Corn Treated with Cd or Pb”
Claim · model-written summary
Common feature of heavy-metal hormetic shoot growth stimulation in corn: increased auxin and flavonol content.
- Taxon
- CornZea mays subsp. mayst0
- Organ / stage
- shoote4
- Treatment
- heavy metalse4
- Outcome
- auxin and flavonol contente4
- Direction
- increasee4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“the common features of the hormetic stimulation of shoot growth by heavy metals are an increase in the auxin and flavonol content”
t0“in Corn Treated with Cd or Pb”
Claim · model-written summary
Hydrogen peroxide was maintained at the same level as control plants during heavy-metal hormetic stimulation in corn.
- Taxon
- CornZea mays subsp. mayst0
- Treatment
- heavy metalse4
- Outcome
- hydrogen peroxidee5
- Direction
- no_changeinferrede5
- Comparator
- control plantse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“the common features of the hormetic stimulation of shoot growth by heavy metals are an increase in the auxin and flavonol content”
e5“the maintenance of hydrogen peroxide at the same level as the control plants”
t0“in Corn Treated with Cd or Pb”
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