Space Magnets Attracting Interest on Earth
Applications of Physical and Biological Techniques In the Study of Gravisensing
and Response System of Plants
The BioTube/Magnetic Field Apparatus (MFA) research is designed to provide
insight into the organization and operation of the gravity sensing systems of
plants and other small organisms. This experiment on STS–107 uses magnetic
fields to manipulate sensory cells in plant roots, thus using magnetic fields
as a tool to study gravity-related phenomena. The experiment will be located in
the SPACEHAB module and is about the size of a household microwave oven.
 |
The goal of the experiment is to improve our understanding of the basic phenomenon
of how plants respond to gravity. The BioTube/MFA experiment specifically examines
how gravitational forces serve as a directional signal for growth in the low-gravity
environment of space. This study will contribute to an improved understanding
of how plants grow and will have important implications for improving plant growth
and productivity on Earth.
In BioTube/MFA, magnetic fields will be used to determine whether the distribution
of subcellular starch grains, called amyloplasts, within plant cells predicts
the direction in which roots will grow and curve in microgravity.
Right: Flax root growing in Magnetic Field Chamber hardware.
|
|
|
|
|
On Earth amyloplasts in plant cells accumulate in the direction of gravity
causing a change in the cell. This essentially translates to a signal indicating
which direction is “up” or “down”. The BioTube/MFA experiment
utilizes high-gradient magnetic fields to change the distribution of amyloplasts
in flax roots. The magnetic field is concentrated at a specific point which produces
magnetic gradient. As the root grows, it approaches the wedge and moves into the
magnetic gradient. The starch grains are then repelled by the magnetic gradient,
causing the roots to curve in the direction of the displaced starch grains. 
|
|
Above:Bioube/MFA in locker.
|
The BioTube/MFA experiment contains dry flax seeds (also known as Linum usitatissimum)
that will germinate in space. The seeds will be watered and the roots will begin
to grow across the highgradient magnetic field wedges in two Magnetic Field Chambers.
A third Magnetic Field Chamber will provide a uniform (non-gradient) magnetic
field for the roots as a comparison to the highgradient magnetic field. Time-lapse
imagery will record pictures of the roots as they grow. Approximately 48 hours
after seed watering, a chemical fixative will preserve the flax specimens for
microscopic analysis and the experiment will end.
The science objectives of the BioTube/MFA experiment address three major questions:
1.) Are amyloplasts the organelles in plant cells that perceive gravity? 2.) Does
the position or movement of the amyloplasts (sedimentation on earth, or, response
to a high gradient magnetic field in orbit) affect the root growth direction?
3.) Does gravity exert an effect on the deposition of cell wall material and the
organization of plant cells organelles?
Background Information:
These goals will provide insight into the fundamental organization and operation
of the gravity response system of plants and determine if, other than the root
cap, other parts of the plant require cues for directional growth.
 |
|
Left: The left panel depicts the random orientation
of amyloplasts in a simulated spaceflight experiment.
The right panel shows the effect of a magnetic force displacing amyloplasts to
the left.
|
 |
|
Left: The left panel belongs to a normal root with the
amyloplasts sedimented to the root cap region. Center panel shows a root cap with
a lateral high-gradient magnetic field displacing amyloplasts to the left. Right
panel shows a gravitationally affected root with amyloplasts sedimented left.
|
Astronauts will turn on the BioTube/MFA experiment three days prior to landing.
All experiment operations will be complete within a 48 hour period. The BioTube/MFA
software automatically controls a series of events that will deliver water to
the seeds, take images of the growing roots and deliver a chemical fixative which
preserves the roots for later analysis. The astronaut crew will periodically check
on the equipment as the experiment progresses and will turn the power off following
chemical fixation.
Science Discipline Supported
The BioTube/MFA research primarily addresses Fundamental Space Biology, but
applies to other disciplines. Similar flight experiments could be conducted on
the International Space Station to increase the knowledge of how biological processes
are affected by microgravity.
Principal Investigator: Dr. Karl H. Hasenstein,
University of Louisiana at Lafayette
Project Manager: David Cox,
Kennedy Space Center Project
Engineer: April Boody,
Kennedy Space Center
Visit Biotube for a
printable PDF version.
Visit http://spaceresearch.nasa.gov/sts-107/overview.html
to learn more about the other OBPR investigations flying on STS-107.
|
