Experiment

Roles of cortical microtubules and microtubule-associated proteins in gravity-induced growth modification of plant stems (Aniso Tubule experiment)

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Easy-to-understand lesson on space experiments: Aniso Tubule experiment
Pikaru, a member of the investigation team in the space experiments, has an interview with the Doctor to closely analyze the Aniso Tubule experiment.

Space experiment report
On the ground, the Principal Investigator, research group members, and JAXA staff are making steady preparations for the space experiment. Recent developments are posted with pictures.

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Background
The development of a rigid plant body may have been one of the critical responses required for plants to survive under 1 g conditions. We have termed this phenomenon ‘gravity resistance’ and have analyzed the nature and mechanisms of gravity resistance using hypergravity conditions produced by centrifugation. As a result, we found that plant body becomes shorter and thicker in proportion to the logarithm of the magnitude of gravity.

Objective
To clarify the mechanisms of gravity resistance, we will examine growth modifications of Arabidopsis hypocotyls in space. We also analyze the changes in dynamics of cortical microtubules and MAPs by observing Arabidopsis hypocotyls expressing green fluorescent protein (GFP) -fused tubulins and MAPs with the fluorescence microscope in the Kibo Module on the ISS.

Outline of the Experiment
GFP-expressing Arabidopsis lines are grown in space. After the incubation, growth modification in epidermal cells of hypocotyl is observed. Dynamics of both cortical microtubules and MAPs in epidermal cells of hypocotyl, labeled with GFP, are also observed.

This is the Point!
If the mechanism of gravity resistance can be clarified, it will enable the controlling of plant forms on Earth. Furthermore, it will be useful for plant cultivation in space, in the future.

This experiment was initiated on November 18, 2013, after delivery of the sample cassettes to the International Space Station (ISS) by KOUNOTORI4, the fourth H-II Transfer Vehicle (HTV4).

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Principal Investigator (PI)
Kouichi SOGA
Graduate School of Science, Osaka City University
Associate Professor
Area of Research: Plant physiology

Links: Website for the Laboratory of Funct. Plant. Biol, Graduate School of Science, Osaka City University