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You are here: N-USOC / Research in Space / Experiments / Skip Navigation LinksSEEDLING GROWTH 2
Seedling Growth 2
9/3/2014 by Carina Helle Berg
The Seedling Growth experiment is designed to study light and gravity signaling in plants and their effects on cell growth and proliferation. This knowledge is valuable for developing an effective use of plants in life support systems in space, including on the Moon and Mars. It also has a strong relevance for improving crop species on earth to obtain increased production and sustainability. This second part of the four-part experiment will be launched and executed on ISS in late 2014.
Through the Seedling Growth experiment, the scientists aim to understand how gravity and light responses influence each other in plants and to better understand the cellular signaling mechanisms involved in plant tropisms. The hypothesis is that positive red-light-sensing, which was known in older plant lineages, is masked by normal 1-g conditions in more recently evolved lineages. Through this experiment, the scientists aim to confirm and characterize the red-light-dependent phototropic response in flowering plants.
Furthermore, the experiment will consider the combined influence of light and gravity on plant development through the identification of changes in the mechanisms and regulation of essential cellular functions. Proliferation and growth of root meristematic cells are the functions to be mechanistically studied, and auxin transport and perception will be analyzed as a regulatory process of these cellular functions, also affecting the developmental pattern of the plant.
Additional objectives of the research are to investigate the relationship between light and gravity and its effects on cellular function by measuring thresholds in fractional gravity, to determine whether the red light effect on blue-light-based phototropism is a direct or indirect effect, and to test whether red light stimulation is capable of counteracting the effects of the gravitational stress on cell growth and proliferation.
The experiment will be conducted with different genotypes of the model plant Arabidopsis thaliana in experimental unique containers placed in the EMCS on the International Space Station. The experiment containers contain white, blue and red lights that can be controlled from ground to expose the plants to different kinds of light. By using the two centrifuges in the EMCS, it is possible to carry out the experiment in microgravity and fractional gravity along with the 1-g control within the same space environment. Following a six day time course in the EMCS, the samples will be either frozen or chemically fixed and returned to the investigators.
Additionally, images will be taken throughout the whole experiment and downloaded real time.
Seedling Growth is divided into four parts. The first part (Seedling Growth 1) was performed in May 2013. Seedling Growth 2 is included in the ISS plans for October 2014. 
The experiment will contribute to a better understanding of light and gravity signaling in plants and is relevant for understanding plant requirements in space. Studying the plants at fractional gravity levels will also improve the understanding of how plants will grow and develop on the Moon and Mars. In addition to increased knowledge on plant space biology, this research will help to develop strategies to optimize light sensing and improve crop plants on earth to obtain increased production and sustainability.
Tropi seed cassettes will be used for Seedling Growth 2.
Experiment name: Seedling Growth 2
Facility: EMCS
Test subject: Arabidopsis thaliana
Experiment duration: 3 runs x 6 days
Growth substrate: Filter paper
Water source: Internal EUE water
Principle Investigator: John Z. Kiss, F. Javier Medina
Payload Developer: NASA Ames Research Center
Launch vehicle: Spx-4
Performance: Planned for October 2014
Point of contact:
Dr. F. Javier Medina, Centro de Investigaciones Biológicas, Madrid, Spain,
Dr. John Z. Kiss, The University of Mississippi,