LIFE CYCLE OF HIGHER PLANTS UNDER MICROGRAVITY CONDITIONS (SPACE SEED)
Research Area: Plant Biology
Expedition(s): 19- 22
Principle Investigator(s): ● Seiichiro Kamisaka, PhD, University of Toyama, Toyama, Japan
RESEARCH OBJECTIVES
In Life Cycle of Higher Plants under Microgravity Conditions (Space
Seed), Arabidopsis thaliana (a small flowering plant) are cultivated in
microgravity to determine the role of gravity in regulating the seed-
to-seed life cycle of higher plants.EARTH BENEFITS
The plant experimental unit (PEU) was developed in collaboration
with JAXA. It is a small plant subsystem that is able to control the
cultivation environment automatically. The PEU can be a basis of
design for large-scale plant factories, which are more efficient on the
ground.SPACE BENEFITS
Plants are vital to long-duration space exploration. Green plants are
valuable not only for food production but also for providing oxygen.
The Space Seed experiment may provide fundamental data covering
plant growth in space.RESULTS
Downlinked images from the Kibo laboratory
demonstrated that seeds started to germinate 3 days
after initial watering, followed by the development of
rosette leaves, flower stalks, flowers, and siliques. Fruit
formation was also observed regardless of the
magnitude of gravity. The rosette leaves under
microgravity remained dark green for longer as
compared to plants grown in the 1G centrifuge,
indicating that leaf senescence is delayed under
microgravity. Microarray analysis of genes involved in
supporting flower stalks revealed that under
microgravity conditions, one gene was downregulated,
while four genes were upregulated, indicating that
microgravity conditions modify the pattern of gene
expression involved in secondary cell formation.
This investigation is complete; however additional results are pending publication.
Photo A and B; Bolting of inflorescences in
Arabidopsis plants grown for 28 days in
Kibo. A, plants grown under microgravity;
B, plants grown under artificial gravity (1.1
G) on a centrifuge. Note that the aging of
rosette leaves is delayed under
microgravity, as compared with 1.1 G.
JAXA image.ISS021-E-006267 NASA
astronaut Nicole Stott,
Expedition 21 flight
engineer, works with the
Cell Biology Experiment
Facility (CBEF) Space
Seed experiment in the
Kibo laboratory of the
International Space
Station. JAXA image.A B