Jacques van Oene
February 1st 05, 02:50 PM
J.D. Harrington
Headquarters, Washington Jan. 31, 2005
(Phone: 202/358-5241)
Holly Wagner
Ohio State University, Columbus, Ohio
(Phone: 614/292-8310)
RELEASE: 05-034
MOSS PROJECT SHOWS HOW SOME PLANTS GROW WITHOUT GRAVITY
Experiments on moss grown aboard two Space Shuttle missions showed the
plants didn't behave as scientists expected them to in the near-absence of
gravity.
The common roof moss (Ceratodon purpureus) grew in striking, clockwise
spirals,
according to Fred Sack. He is the study's lead investigator and professor of
plant cellular and molecular biology at Ohio State University, Columbus,
Ohio.
The researchers expected random, unorganized growth as seen with every other
type
of plant flown in space. "We don't know why moss grew non-randomly in space,
but
we found distinct spiral patterns," Sack said. The findings are reported in
the
online edition of the journal, Planta.
Common roof moss is a relatively primitive plant in which certain cells,
called
tip cells, are guided by gravity in their growth. This gravity response is
only
seen when moss is kept in the dark, as light overrides gravity's effect.
Moss originates from chains of cells with growth only taking place in the
tip-
most cell of a chain. When grown in the dark, the tip cells grow away from
gravity's pull - this gets the cells out of the soil and into the light.
"The way these tip cells respond to gravity is exceptional," Sack said. "In
most
plants, gravity guides the growth of roots or stems, which are made up of
many
cells. But in moss, it is just a single cell that both senses and responds
to
gravity," he added.
Common roof moss was grown in Petri dishes in lockers aboard Shuttle
missions in
1997 and 2003. The second mission was the Space Shuttle Columbia (STS-107),
which
broke apart during reentry on Feb. 1, 2003. Most of the hardware holding the
plants was recovered, and 11 of the recovered moss cultures were usable.
Astronauts followed similar experimental procedures on both flights. They
chemically "fixed" the moss cultures before each mission reentered Earth's
atmosphere. This process stopped all growth in the moss, capturing their
state
during flight.
Control studies conducted at NASA's Kennedy Space Center (KSC) in Florida
used
hardware and procedures similar to those used aboard each flight. However,
these
moss cultures were either kept stationary or turned at a slow spin on a
clinostat
- a machine resembling a record turntable placed on its edge. It is used to
negate the effects of gravity.
On Earth, gravity controls the direction of moss growth thoroughly; it grows
straight away from the center of the Earth, just like shoots in a field of
corn.
In space, scientists expected the cells to grow erratically in all
directions,
since there was no gravity cue.
Instead, the moss grew non-randomly in two successive types of patterns: The
first pattern resembled spokes in a wheel. The cells grew outward from where
they
were originally sown. Later, the tips of the filaments grew in arcs, so the
entire culture showed clockwise spirals. The same patterns were found when
the
moss was grown on a clinostat on the ground.
"The results are unusual, as this is the first time researchers report
seeing
this kind of plant growth response in space." Sack said.
"Unlike the ordered response of moss cells in space, other types of plants
grow
randomly," he said. "So in moss, gravity must normally mask a default growth
pattern. This pattern is only revealed when the gravity signal is lost or
disrupted." Sack added.
Sack conducted the study with Volker Kern, who is now at KSC. Kern was at
Ohio
State during the study; David Reed, with Bionetics Corp. based at KSC;
former
Ohio State colleagues Jeanette Nadeau, Jochen Schwuchow and Alexander
Skripnikov;
and with Jessica Lucas, a graduate student in Sack's lab.
-end-
--
--------------
Jacques :-)
www.spacepatches.info
Headquarters, Washington Jan. 31, 2005
(Phone: 202/358-5241)
Holly Wagner
Ohio State University, Columbus, Ohio
(Phone: 614/292-8310)
RELEASE: 05-034
MOSS PROJECT SHOWS HOW SOME PLANTS GROW WITHOUT GRAVITY
Experiments on moss grown aboard two Space Shuttle missions showed the
plants didn't behave as scientists expected them to in the near-absence of
gravity.
The common roof moss (Ceratodon purpureus) grew in striking, clockwise
spirals,
according to Fred Sack. He is the study's lead investigator and professor of
plant cellular and molecular biology at Ohio State University, Columbus,
Ohio.
The researchers expected random, unorganized growth as seen with every other
type
of plant flown in space. "We don't know why moss grew non-randomly in space,
but
we found distinct spiral patterns," Sack said. The findings are reported in
the
online edition of the journal, Planta.
Common roof moss is a relatively primitive plant in which certain cells,
called
tip cells, are guided by gravity in their growth. This gravity response is
only
seen when moss is kept in the dark, as light overrides gravity's effect.
Moss originates from chains of cells with growth only taking place in the
tip-
most cell of a chain. When grown in the dark, the tip cells grow away from
gravity's pull - this gets the cells out of the soil and into the light.
"The way these tip cells respond to gravity is exceptional," Sack said. "In
most
plants, gravity guides the growth of roots or stems, which are made up of
many
cells. But in moss, it is just a single cell that both senses and responds
to
gravity," he added.
Common roof moss was grown in Petri dishes in lockers aboard Shuttle
missions in
1997 and 2003. The second mission was the Space Shuttle Columbia (STS-107),
which
broke apart during reentry on Feb. 1, 2003. Most of the hardware holding the
plants was recovered, and 11 of the recovered moss cultures were usable.
Astronauts followed similar experimental procedures on both flights. They
chemically "fixed" the moss cultures before each mission reentered Earth's
atmosphere. This process stopped all growth in the moss, capturing their
state
during flight.
Control studies conducted at NASA's Kennedy Space Center (KSC) in Florida
used
hardware and procedures similar to those used aboard each flight. However,
these
moss cultures were either kept stationary or turned at a slow spin on a
clinostat
- a machine resembling a record turntable placed on its edge. It is used to
negate the effects of gravity.
On Earth, gravity controls the direction of moss growth thoroughly; it grows
straight away from the center of the Earth, just like shoots in a field of
corn.
In space, scientists expected the cells to grow erratically in all
directions,
since there was no gravity cue.
Instead, the moss grew non-randomly in two successive types of patterns: The
first pattern resembled spokes in a wheel. The cells grew outward from where
they
were originally sown. Later, the tips of the filaments grew in arcs, so the
entire culture showed clockwise spirals. The same patterns were found when
the
moss was grown on a clinostat on the ground.
"The results are unusual, as this is the first time researchers report
seeing
this kind of plant growth response in space." Sack said.
"Unlike the ordered response of moss cells in space, other types of plants
grow
randomly," he said. "So in moss, gravity must normally mask a default growth
pattern. This pattern is only revealed when the gravity signal is lost or
disrupted." Sack added.
Sack conducted the study with Volker Kern, who is now at KSC. Kern was at
Ohio
State during the study; David Reed, with Bionetics Corp. based at KSC;
former
Ohio State colleagues Jeanette Nadeau, Jochen Schwuchow and Alexander
Skripnikov;
and with Jessica Lucas, a graduate student in Sack's lab.
-end-
--
--------------
Jacques :-)
www.spacepatches.info