Gravitropism

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Gravitropism

• Hannah McCullough (Ritchie)
• Zak Stewart (Weirton Madonna)
• Jason DeBerry (Preston)

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What is Gravitropism?

• A growth process that orients tissues in a
  gravitational field
• Roots, shoots, and leaves have distinct
  orientations to gravity

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Central Research Questions

• How will a pea plant orientate itself when placed
  at different angles?
• How much of the stress hormone ethylene is
  produced when experiencing reorientation?

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Experimental Design

• Control group pea plant growing up-right
• Upright then placed horizontally
• 24-hr group
• 90-min group

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Time Lapse Video (1)
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• Pea plants with one re-orientation

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Time Lapse Video (2)
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Pea plants with a second re-orientation
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Ethylene

• It is a plant hormone that virtually all plant
  tissue produces
• More ethylene is produced when a plant
  experiences stress

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Gas Chromatography (GC)

• GC is used to measure ethylene levels in plants
• Ethylene levels were measured in both the control
  group and experimental groups

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GC Results
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Scanning Electron Microscope (SEM)

• The SEM is a high powered microscope capable of
  magnifying up to 200,000 times with a resolution
  of 25 Å
• Pea plant cells were observed through the SEM

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SEM Pictures
Cross-section of pea stem
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Conclusion

• When a plant begins to re-orientate itself, it
  starts curving at the tip and continues growing
  in the new direction
• Ethylene levels did increase when the pea plant
  experienced a change in orientation

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The Group
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Acknowledgements

• Dr. Marcia Harrison
• Dr. Nicola LoCascio
• David Neff (SEM Tech.)
• Justin Hogan