Related Experiment Video
Updated: May 3, 2026
13:35
Fluorescence Activated Cell Sorting of Plant Protoplasts
Published on: February 18, 2010
24.5K
In-vitro auxin binding to particulate cell fractions from corn coleoptiles
R Hertel1, K S Thomson, V E Russo
1Institut für Biologie III, Universität Freiburg i.Br., Germany.
Planta
|January 31, 2014
Summary
Radioactivity from plant hormones like auxin binds to specific particles in corn coleoptiles. This binding is specific to auxins and suggests their receptors are located at the plasma membrane.
Area of Science:
- Plant Biology
- Molecular Biology
- Biochemistry
Background:
- Plant hormones, particularly auxins, play critical roles in plant growth and development.
- Understanding the molecular mechanisms of auxin action, including receptor localization, is crucial for plant science.
Purpose of the Study:
- To investigate the binding characteristics of auxin in plant tissues.
- To identify potential auxin binding sites and their cellular localization.
Main Methods:
- In vitro binding assays using radiolabeled auxins (IAA and NAA) with corn coleoptile homogenates.
- Saturation kinetics analysis to determine binding parameters (K M, site concentration).
- Competition assays with various compounds to assess binding specificity.
Main Results:
- Radioactivity from labeled auxins reversibly bound to pelletable particles in corn coleoptile homogenates.
- Binding exhibited saturation kinetics, indicating specific binding sites with an apparent K M between 10(-6) M and 10(-5) M.
- Binding was auxin-specific, with only auxins and known auxin analogues interfering with the process.
- Auxin-binding fractions were devoid of DNA and cytochrome-c oxidase but contained binding sites for 1-naphthylphthalamic acid.
Conclusions:
- The study provides biochemical evidence for specific auxin binding sites in corn coleoptiles.
- Results support the hypothesis that auxin receptors are localized at the plasma membrane, consistent with physiological data.
