Found In Space

While the general public focused on John Glenn's return to space last October (1998), plant biologists Mike Evans and Hideo Ishikawa and their students scrambled to get their plant experiment ready to share shuttle space with Glenn. Not knowing until January that shuttle space would be available presented definite problems. But they resolved to seize this opportunity to fine-tune their experiment for its later debut on the International Space Station-the first American experiment approved by any space agency for the ISS.

Their plant-growth experiment, funded by the Japanese Space Agency (NASDA), was ranked the highest of all plant proposals received and assigned priority space on the JEM (Japanese Experimental Module) of the ISS.

When NASDA, which had been offered shuttle space by NASA, asked Evans and Ishikawa if they could use the space for preliminary tests of their Space Station experiment, they agreed it was worth the intense effort required. Earlier experiments showed the researchers that cells in the distal elongation zone, or DEZ, a region near the root tip, play an important role in the way plant roots respond to stimuli. These cells clearly differ physiologically from those in the main cell elongation zone. These studies are important for a basic understanding of how plants work on earth as well as developing plans for successful plant cultivation in space.

Preliminary tests indicated that the growth of these cells is somehow controlled by tiny electrical currents that the cells generate. But when Evans and his colleagues attempted to test the response of these cells to applied electrical fields, the results were complicated by the strong effect of the earth's gravity on the response pattern.

The shuttle experiment was a chance to examine very specifically the way the DEZ responds to electrical stimulation in the near absence of gravity. Using video cameras and computers running highly-sophisticated software developed by Ishikawa (copyrighted by Ohio State), the researchers can access substantially more data than by traditional methods of examining plant growth.

Everyone in Evans' lab-including four grad and four undergrad students-geared up for the challenge. With numerous preliminary tests and mind-boggling details to work out, it could have been overwhelming. "Luckily, NASDA grant funds allowed us to hire more students, each of whom was assigned to their own sub-project, which helped us nail down all the variables of the experiment," Evans says.

The undergraduates had a wonderful research opportunity and they made valuable and highly- necessary contributions to the team. Graduate students Chris Wolverton and Jack Mullen coordinated all the other students' work.

So what have they found, now that the dust has settled? "Well, we have lots of data," Evans says. "The major finding-that really surprised us, is that the sensitivity of roots to electricity is strongly shifted in space-these are completely different results from what we expected. Electrical stimulation that causes redistribution of growth patterns on earth, causes suppression of growth in space. To examine why the electrical control of growth is so different in the absence of gravity, we need the Space Station experiment."

In 1999, the researchers received new NASA and NSF funding to establish an international plant growth imaging data bank for coordinating research on plant growth, a counterpart of gene banks with their maps of DNA. "The image bank gives a really good picture of the function of plant-growth systems," Evans says.

Life continues to be lived in the fast lane in the Evans-Ishikawa lab. The goal for the experiment is to be ISS-ready by 2003. This is the critical definition phase of the experiment. Not only must it be good science, but it must be able to be done under Space Station limitations. Evans and Ishikawa plan to coordinate an international collaboration involving researchers here and in Japan, all of whom are focused on fine-tuning every detail by 2003.