Crew involvement in experiments allows for more complex experimental design and
analyses. For example, two tropism experiments, one with wheat, called Phototropic
Transients (FORTRAN), and another with oat, called Gravitational Threshold (GTH-
RES), were performed on the space shuttle implementing the International
Microgravity Laboratory payload (IML-1; Heathcote et al. 1995a; Brown et al. 1995).
These experiments were performed on the Spacelab module of the space shuttle mis-
sion STS-42 in 1992. Plants in these experiments were transported to the shuttle in
specially designed containers called Plant Carry-On Containers (PCOCs). Once on-
board, the containers were stowed in either the Mid-deck Ambient Stowage Insert
(MASI) or housed in the Gravitational Plant Physiology Facility (GPPF). In the GPPF,
plants were placed in containers called Plant Cubes, which had a window that allowed
infrared radiation but no visible light to penetrate, and a second window that allowed
blue light to penetrate during photostimulation periods. Photostimulation occurred
when plants were placed on the Recording and Stimulus Chamber (REST). A culture
rotor, which consisted of two centrifuges, provided a force of 1g, and a test rotor, which
provided 0 to 1g, were both available for video recording of curvature responses to
different gravitational accelerations. Ground controls for these experiments included a
clinostat in a GPPF facility. These procedures required crew time to transport con-
tainers and perform the experiments, but also allowed for controls to be grown in
space.
Biorack is another facility that has been used to study tropisms in the space environ-
ment. It was developed by the ESA as a multi-user facility to study a variety of biologi-
cal materials (Manieri et al. 1996). The Biorack facility had a cooler/freezer, a glovebox,
and two incubators. Two types of containers have been available for studying biological
specimens in the Biorack facility. Type I containers hold a volume of 65 ml and Type II
containers hold a volume of 385 ml. Both Arabidopsisand lentil seedlings have been ger-
minated and grown in Type I containers with Type II containers used as fixation devices
(Perbal et al. 1987; Kiss et al. 1999). This hardware allowed for video monitoring of plant
growth and curvature responses and, with the aid of the crew, the plants could be chemi-
cally fixed to study the movement of amyloplasts in gravity-perceiving cells once the
samples had been returned to Earth.
Ideally, in these spaceborne experiments, all environmental parameters except the one
being studied should be controlled and monitored, including temperature, humidity, gas
phase composition, and light intensity. A new facility called the European Modular
Cultivation System (EMCS) has been developed by the ESA to study plant growth on the
ISS. Applications of the EMCS to other biological systems are also being explored. The
EMCS has also addressed the requirement to monitor many of the environmental param-
eters outlined above (Figure 8.4) (Brinckmann and Brillouet 2000; Brinckmann 2005).
The EMCS has an incubator with two centrifuges, atmospheric and humidity control, eth-
ylene scrubbers, video monitoring, and Experiment Containers (ECs) that interface with
the Experiment Unique Equipment (EUE). The EUE can be custom-designed for each ex-
periment’s requirements. A project is in development to study tropisms in Arabidopsis
seedlings using the EMCS and video images, and frozen tissues will be returned to Earth
for analyses (Correll et al. 2005).
frankie
(Frankie)
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