This is one of those very basic yet simple questions that needed to
be answered. That the answer turns out to be unconditional is a
bonus. We can grow plants happily in space. We all expected that
doing so would become both necessary and doable. Now we know it is
doable.
We will soon be considering how to do the engineering as our access
to space gets serious and expansion begins in earnest. Bubbles on
the moon are particularly attractive. I wonder if it may be possible
to produce an active cellular structure of hexagonal units framing
water filled bubbles that also contain living algae to assist in
filtering the incoming radiation from the sun. The plumbing would be
a challenge of course but not impossible.
Such a construct would provide excellent living space inside for
humanity. It will still be much easier to operate underground with a
mile of rock providing protection to the dome.
Plants Grow Fine
Without Gravity
New finding boosts the
prospect of growing crops in space or on other planets.
James Owen
for National
Geographic News
Published December 7,
2012
When researchers sent
plants to the International Space Station in 2010, the
flora wasn't meant to be decorative. Instead, the seeds of these
small, white flowers—called Arabidopsis thaliana—were the
subject of an experiment to study how plant roots developed in a
weightless environment.
Gravity is an
important influence on root growth, but the scientists found that
their space plants didn't need it to flourish. The research team from
the University of Florida in Gainesville thinks this ability is
related to a plant's inherent ability to orient itself as it grows.
Seeds germinated on the International Space Station sprouted roots
that behaved like they would on Earth—growing away from the
seed to seek nutrients and water in exactly the same pattern observed
with gravity. (Related: "Beyond Gravity.")
Since the flowers were
orbiting some 220 miles (350 kilometers) above the Earth at the time,
the NASA-funded experiment suggests that plants still retain an
earthy instinct when they don't have gravity as a guide.
"The role of
gravity in plant growth and development in terrestrial environments
is well understood," said plant geneticist and study
co-author Anna-Lisa Paul, with the University of Florida in
Gainesville.
"What is less
well understood is how plants respond when you remove gravity."
(See a video about plant growth.)
The new study revealed
that "features of plant growth we thought were a result of
gravity acting on plant cells and organs do not actually require
gravity," she added.
Paul and her
collaborator Robert Ferl, a plant biologist at the University of
Florida in Gainesville, monitored their plants from the Kennedy Space
Center in Florida using images sent from the space station every six
hours.
Root Growth
Grown on a
nutrient-rich gel in clear petri plates, the space flowers showed
familiar root growth patterns such as "skewing," where
roots slant progressively as they branch out.
"When we saw the
first pictures come back from orbit and saw that we had most of the
skewing phenomenon we were quite surprised," Paul said.
Researchers have
always thought that skewing was the result of gravity's effects on
how the root tip interacts with the surfaces it encounters as it
grows, she added. But Paul and Ferl suspect that in the absence of
gravity, other cues take over that enable the plant to direct its
roots away from the seed and light-seeking shoot. Those cues could
include moisture, nutrients, and light avoidance.
"Bottom line is
that although plants 'know' that they are in a novel environment,
they ultimately do just fine," Paul said.
The finding further
boosts the prospect of cultivating food plants in space and,
eventually, on other planets.
"There's really
no impediment to growing plants in microgravity, such as on a
long-term mission to Mars, or in reduced-gravity environments such as
in specialized greenhouses on Mars or the moon," Paul said.
(Related: "Alien Trees Would Bloom Black on Worlds With
Double Stars.")
The study findings
appear in the latest issue of the journal BMC Plant Biology.
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