Experiment

Hydro Tropi Experiment Begins

* All times are Japan Standard Time (JST)

Hydrotropism and Auxin-Inducible Gene Expression in Roots Grown under Microgravity Conditions (Hydro Tropi)*, began on board Kibo.

* Principal Investigator (PI): Hideyuki Takahashi (Professor of Graduate School of Life Sciences, Tohoku University)

Hydro Tropi investigates effect of water on the orientation of root growth to clarify relation between the water and the roots.

Sample seedlings (dried cucumber seeds) were launched to the International Space Station (ISS) aboard the space shuttle Atlantis (STS-132 mission) on May 15, 2010. Aboard the ISS, the seedlings were stored until the experiment begins.

The experiment began at 1:27 a.m. on October 19, 2010, by commands sent from the Tsukuba Space Center (TKSC). Sample preparation was performed by ISS crew members prior to the experiment.

The experiment has two major objectives. One is to see if roots of cucumber seedlings will bend toward water when they grow in microgravity. The other is to identify Auxin-regulated genes. Auxin, a plant hormone, is known to play a key role in root bending process.

In preparation for the experiment, dried cucumber seeds are inserted into a PVA sponge, and the sponge is placed in a container. The experiment will begin by poring water to the PVA sponge. In the container, the cucumber seeds will be germinated and grown for 18 hours. After that, an artificial moisture gradient will be provided in the container to observe the direction of the root growth.

Root samples will be collected at 18 hours, 22 hours, and 41 hours after initiation of the experiment. The samples will be chemically fixed and stored in the station's refrigerator/freezer, MELFI.

The collected samples will be returned to the ground aboard the space shuttle Discovery (STS-133 mission), which is scheduled to launch in November 2010.

If the mechanism by which roots respond to water is understood, the nature will be applied to the root growth orientation control under a particular environment such as development of space agriculture system in the future.

Hydrotropism and Auxin-Inducible Gene Expression in Roots Grown under Microgravity Conditions (Hydro Tropi)

Special Message from Principal Investigator (PI)

We were at the UOA at the time the experiment was scheduled to begin. It seemed to me that the experiment began on time, because we did not receive any call or notice of schedule change. One hour later, the rotor of the Cell Biological Experiment Facility (CBEF) began moving and we confirmed the cucumber seeds in the V-MEU through video images downliniked from the ISS. That was when we felt sure that there was nothing wrong with the experiment.

Hydro Tropi team monitoring the experiment from the UOA
(Center: Professor Takahashi)

*All times are Japan Standard Time (JST)