Friday, June 22, 2012

Why NASA Grows Space Sunflowers

An unexpected passenger aboard the International Space Station is sick and could die.

"I am afraid that if something is not done we are going to lose Sunflower," U.S. astronaut and ISS resident Don Pettit wrote on his blog on May 5. "Our spacecraft is designed for animals so life can be a struggle for plants."

The sunflower in question, which Pettit has been trying to grow in the ISS, is afflicted with a fungal blight that has spotted its leaves. This ailment has afflicted other sunflowers grown in space: In 1982 in preparation for a space experiment called HEFLEX (see below), space sunflowers suffered a similar blight. Back then NASA adopted sterilization techniques, and the fungus did not reappear when the experiment flew in 1983.

NASA spokesmen say, however, that Pettit brought sunflower seeds to grow on his own time. Because it is not part of any official experiment, the sunflower was seemingly not protected by the previously learned sterilization. Nor is the crew equipped to save it. "The crew medical kit is designed for animals, not plants, so there are no medications for this disease," Pettit wrote. "Treating Sunflower with a disinfectant wipe that has an antibacterial agent called benzalkonium chloride. We do not know if this is going to work." The latest news from orbit is that the antibacterial wipes are helping.

Pettit?s outer-space botany isn?t just a weird experiment. Here are some of NASA?s pioneering projects that show its relationship to sunflowers is not a new phenomenon.

1. Moon material tests, Apollo 11 and 12


Hardware: Lunar Receiving Laboratory

Scientists were pretty sure the moon was sterile before astronauts went there. But it?s better to be safe than sorry when it comes to starting space plagues. So NASA set up a biosafety level 3 facility to test lunar materials? effect on various life forms on Earth. In it, various plant and animal cells were exposed to lunar soil, called regolith, to see if anything harmful was present. Sunflower cells were one of the organisms tested. Rather than being harmed, the cells showed higher than normal concentrations of fatty acids after exposure to the regolith. After Apollo 12, it became clear that the moon was, indeed, sterile.

2. Helianthus Flight Experiment (HEFLEX)


Hardware: SpaceLab 1, Space Shuttle Columbia

In 1983 the space shuttle ferried sunflower seedings into space to study nutation, where a plant?s tip slowly rotates downward as it grows, anchoring the plant as it screws into the soil. Charles Darwin discovered this in 1880, but he could never explain how the plant established the correct direction to grow. No one else could figure that out either. Some said the plants react to gravity. So what better way to test this theory than to grow sunflowers in space?

What followed was HEFLEX. Scientists examined sunflower seedlings for perfection and chose the best ones 12 hours before launch. After the launch, the sunflowers? growth was monitored via video cameras. The initial result: The seedlings rotated as they grew, despite the total absence of gravity. The research also recorded some microgravity experiments?the roots rotated in wider circles as gravity decreased. But gravity was not required to start the nutation, so Darwin?s mystery endures.

3. Zero-G Cellular Electrofusion


Hardware: Space Shuttle Columbia

Electrofusion?combining cells using electricity?is one way to create new plant hybrids. Take two cell types, zap them for 10 minutes or so, and the cytoplasmic contents will mingle. The combined cell can then be grown as any other cloned hybrid.

In 1993 scientists created sunflower hybrids in space using this method. Why? On Earth, the bridges between the fused cells are prone to collapse. The researchers figured that the absence of gravity would enable the hybrids to be more stable and give them a chance to grow. They were right, at least when it came to sunflowers: The fused protoplast pairs stabilized and grew normally in space and later on the ground. However, tobacco and digitalis plants subjected to the same experiment failed. No one knows why.

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