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You are here: N-USOC / Research in Space / Experiments / Skip Navigation LinksTROPI-2
10/18/2012 by Carina Helle Berg
In the same way as the Tropi Experiment, performed in the EMCS on ISS in 2006, Tropi2 aimed to study the cellular mechanisms of phototropism of Arabidopsis thaliana and the effects of gravity on light perception. Since Tropi2 was a direct re-flight of Tropi the scientific objectives remained unchanged.
However, in addition to studying plants in microgravity, Tropi2 also considered tropisms in fractional or partial gravity provided by the EMCS centrifuge.
In specific the experiment aimed to:
* Characterize the novel red-light-dependent positive phototropic system and the blue-light-dependent negative phototropic system in roots and hypocotyls in the absence of the complicating effects of gravity.
* Examine the tropistic response of seedlings in fractional gravity
* Investigate the role of specific photoreceptors in the phototropic response.
* Optimize growth and developmental conditions for Arabidopsis thaliana in spaceflight hardware.
The picture to the right shows seedlings growing in white light in an EC (shown with all five seedling cassettes) at the end of the growth phase of the time line during the spaceflight experiment. Cassettes 01–05 (labeled on the membrane) contain WT, phyB, WT, phyA, and phyB seedlings, respectively. The unidirectional white illumination is from LEDs along the long axis of the cassette, and the values on the left of the image indicates Greenwich Mean Time and EC number.(


The picture above shows a higher magnification image of phyB seedlings growing in white light at the end of the growth phase of the time line during the spaceflight experiment. The distance between grid lines on the membranes is 3 mm, and the number (29) on the membrane refers to the specific seedling cassette. B2 on the image indicates the EC number.
Tropi seed cassettes were used for Tropi2
Experiment name:          Tropi-2
Facility:                            EMCS
Test subject:                    Arabidopsis thaliana
Experiment duration:    2 runs x 6 days
Growth substrate:          Filter paper
Water source:                 Internal EUE water
Principle Investigator:  John Z. Kiss
Payload Developer:       NASA Ames Research Center
Launch vehicle:               Shuttle mission 20A               
Performance:                   2010
Related articles:
Kiss J.Z., K.D.L. Millar, R.E. Edelmann.  2012. Phototropism of Arabidopsis thaliana in microgravity and fractional gravity on the International Space Station. Planta 236:635–645.


Kiss J.Z.,  K.D.L. Millar,  P. Kumar, R.E. Edelmann, M.J. Correll. 2011.  Improvements in the re-flight of spaceflight experiments on plant tropisms. Advances in Space Research 47:545–552.


Point of contact:
Principal Investigator: Dr. John Z. Kiss,