ROOM
50
Astronautics
this led to the assumption that one of the most
important factors that influenced the growth and
development of plants in the Svet greenhouse was
high levels of ethylene.
The first measurements of ethylene in the Mir
atmosphere showed an average concentration of 1.1
mg/m³, a perfectly safe concentration for humans.
Higher levels of ethylene in the atmosphere in Earth
control conditions also led to increased tillering
(shooting from the root or bottom of the original
stalk) without changing the plant mass, a shorter
culm and no viable seeds.
The next Russo-American experiment in the
summer of 1997 planned to grow a model short-
cycle plant, Brassica rapa L. in two generations.
And for the first time in history it was a success!
Brassica turned out to be more tolerant to higher
ethylene concentrations in the station’s atmosphere
and it produced viable seeds both in the first space
generation and in re-seeding of those seeds in the
space greenhouse.
Ethylene did, however, cause serious changes in
the plants – all morphometric characteristics, such
as plant height, number of pods and seed mass,
turned out to be half of their Earthly counterparts.
In 1998-1999 we repeated the experiment on
growing two-generation plants on Mir but this
time with wheat – a more interesting plant in terms
of future life support systems. The USU-Apogee
type of wheat was selected for better tolerance
to ethylene and the variety chosen was created
by researchers at Utah State University under
the leadership of Bruce Bugbee, especially for
greenhouses of various bioregenerative life support
systems, including those in space.
Both experiments on Mir resulted in viable wheat
seeds, and the space plants did not differ in their
morphology from the Earth plants.
the Earth control group, with similar low light, the
plants still formed heads, albeit sterile ones without
seeds. This led to the conclusion that some negative
factor had affected the wheat in flight, a theory that
was confirmed by the next experiment in 1996.
This time, the wheat grew and formed heads but
it was obvious from photographs and videos that
something strange was going on with the plants.
When the materials were delivered to the Russo-
American team back on Earth we were all shocked
to discover that in almost 300 fully formed wheat
plants there wasn’t a single seed!
The plants also showed significant morphological
changes. Compared to Earth-control plants the
microgravity plants had almost three times as many
heads, while the culm (stem) was half the length,
the head mass half the weight, the flower head
length was shorter, and there were less spikelets in
a head though the average number of flowers in the
spikelets was higher.
Microscopic cytoembryological analysis of the
biological materials showed that the lack of seeds in
the heads was due to utterly sterile pollen.
Morphological and cytoembryological changes
in the plants that had grown in space were in many
ways similar to the results described in literature on
ectogenous use of ethylene and ethylene-containing
products, which are strong phytohormones, and
During lengthy
flights an
experiment
where
something
is grown can
find a wide
range of uses
not only in
scientific
research
but also for
psychological
support
DEVELOPING TASTE
For the final experiment in the Svet greenhouse on
Mir in 2000, the flavour of leafy vegetables grown in
weightlessness was evaluated by the cosmonauts.
Tasting the greens, cosmonauts Aleksandr Kaleri
and Sergey Zaletin remarked that adding fresh
greens to a crews’ diet would be very desirable,
particularly if they were spicy rather than bland.
Later on, cosmonaut Maksim Surayev wrote about
the lack of flavour: “Roma (Roman Romanenko) was
growing some sort of salad on the space station. And
the salad was so green, Roma obviously wanted to
eat it. I too really wanted to eat it! But back on Earth
they wouldn’t allow it. They said – you have to freeze
it and send it back to Earth for science!
“Imagine this green salad, and two young healthy
cosmonauts staring at it, unable to try it! We decided
nothing awful would happen if we just tried a tiny
piece. So we chewed some. Such a disappointment -
because the greens had absolutely no taste!
“When I was planting my own salad, I found some
wheat seeds that had been left behind by another
expedition and I sneaked them in and planted them
too. But then the scientists from Earth told me to get
rid of the wheat.
“I’m sorry, dear scientists, I couldn’t do it – it was
growing so beautifully! Just look at the heads on this
wheat! And I really do hope that they turn out tastier
than Roma’s salad!”
Cosmonaut Sergey
Volkov, the seed-to-seed
cycle of the super-dwarf
wheat growing
experiment in the ‘Lada’
greenhouse on the
International Space
Station in 2011.
