Download Brassinosteroids - Catawba County Schools

By: Adam Cline, Macy Franklin, Jared Davis, and
Kerigan “K-Money” Farley
Molecular Formula
Background Info
 Similar to cholesterol and sex hormones in animals
 Present in all plant tissues
 Internally produced and act near site of synthesis
Origin
 Pollen, seeds, and most other plant tissues
produce brassinosteroids
Where it starts
 Intracellular reception starts the phosphorylation of
the steroid
Where is stops
 In the nucleus where it attaches and turns on the gene
that promotes plant growth
Functions
 Promotes cell expansion and division shoots
 Root growth at low concentrations
 Stops root growth at high concentrations (negative
feedback)
 Promotes xylem differentiation and inhibit phloem
differentiation
 Promotes seed germination and pollen tube elongation
 So similar to auxins that it took years to determine they
were not just types of auxins
Flow Chart
Signal
Transduction
The steroid binds to the
intracellular BR1 Kinase and
starts the phosphorylation
cascade.
Series of events occur that lead to
transcription factors that turn on
specific genes.
Response
This gene that produces a protein
that promotes cell growth in the
roots, leaves, and stems of the
plant. It will also increase plant
production.