Posts Tagged ‘Plants’

The Mystery of the Missing Moon Trees

18 Feb

15 years after NASA astronomer David Williams started searching for them, hundreds of trees grown from space-faring seeds are still missing.

The “moon trees,” whose seeds circled the moon 34 times in Apollo 14 astronaut Stuart Roosa’s pocket, were welcomed back to Earth with great fanfare in 1971. One was planted in Washington Square in Philadelphia as part of the 1975 bicentennial celebrations. Another took root at the White House. Several found homes at state capitals and space-related sites around the country. Then-president Gerald Ford called the trees “living symbol[s] of our spectacular human and scientific achievements.”

And then, mysteriously, everyone seemed to forget about them.

“The careful records weren’t kept, or if they were kept they weren’t maintained,” Williams said. Williams, whose job includes archiving data from the Apollo missions, hadn’t even heard of the moon trees until a third grade teacher e-mailed him in 1996 to ask about a tree at the Camp Koch Girl Scout Camp in Cannelton, Indiana.

“No one around here had ever heard of it,” Williams said. “This is such a neat story, and no one seems to know about it.”

Williams has made it his mission to find them. For the past 15 years, he has kept a record on the web of every known tree’s location. When he started in 1996, he only knew where 22 trees were found. Now, that number has climbed to 80.

But the climb is slow. Mostly, Williams heard of new trees when a hiker or a park visitor found one and e-mailed him about it. The e-mails are ever fewer and farther between, he says.

“It’s been sort of a trickle,” he said. “Most of the easy ones, the low-lying fruit had already been gathered.”

Although most of the trees are long-lived species expected to last centuries, some have started to die off. According to Williams’ most recent tree count, 21 of the 80 known trees are dead, including the Loblolly pine outside the White House, five sycamores and two pines outside the U.S. Space and Rocket Center in Huntsville, Alabama, and one New Orleans pine that was damaged in Hurricane Katrina.

“It’s kind of sad, to see them going,” Williams said.

The trees’ poor health has nothing to do with their journey to space, Williams says.

“No one knew for sure whether being exposed to weightlessness or radiation would do something to the seeds,” he said. “They grew control trees right next to each other to see if they grew differently. But they didn’t find anything.”

The healthy trees have given rise to a crop of half-moon trees, trees grown from the seeds of a moon tree.

“There’s a lot of second generation moon trees being planted now,” Williams said. “That’s getting to the point where I can’t keep up with it.”

You can even buy half-moon seeds online and plant one in your own yard. Williams’ yard hosts a second generation moon tree, a gift from the National Arboretum.

Although Williams will keep looking, there’s no way to know when he’s found them all, he says. But at least the trees won’t be forgotten again.

“At least now there’s a permanent home for it,” he said. “It can’t be lost now. At least all the information that comes in, we have that.”

Update: If you think you’ve found a moon tree, you can contact Williams at [email protected]. Check the Moon Trees website to see if your tree has been reported before.

Image: 1) The plaque labeling the moon tree at NASA’s Goddard Spaceflight Center, where Williams works. 2) NASA Goddard’s moon sycamore. (Courtesy Jay Friedlander.)

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04 Nov

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The smell of freshly-cut grass is actually a plant distress call [Mad Science]

26 Aug
The lovely scent of cut grass is the reek of plant anguish: When attacked, plants release airborne chemical compounds. Now scientists say plants can use these compounds almost like language, notifying nearby creatures who can "rescue" them from insect attacks. More »

Newly Discovered Chlorophyll Catches Infrared Light

20 Aug

A new kind of chlorophyll that catches sunlight from just beyond the red end of the visible light spectrum has been discovered. The new pigment extends the known range of light that is usable by most photosynthetic organisms. Harnessing this pigment’s power could lead to biofuel-generating algae that are super-efficient, using a greater spread of sunlight than thought possible.

sciencenews“This is a very important new development, and is the first new type of chlorophyll discovered in an oxygenic organism in 60 years,” says biological chemist Robert Blankenship of Washington University in St. Louis.

The newfound pigment, dubbed chlorophyll f, absorbs light most efficiently at a wavelength around 706 nanometers, just beyond the red end of the visible spectrum, researchers report online August 19 in Science. This unique absorbance appears to occur thanks to a chemical decoration known as a formyl group on the chlorophyll’s carbon number two. That chemical tweak probably allows the algaelike organism that makes chlorophyll f to conduct photosynthesis while living beneath other photosynthesizers that capture all the other usable light.

“In nature this very small modification of the pigment happens, and then the organism can use this unique light,” says molecular biologist Min Chen of the University of Sydney in Australia. Chen and her colleagues identified the new pigment in extracts from ground-up stromatolites, the knobby chunks of rock and algae that can form in shallow waters. The samples were collected in the Hamelin pool in western Australia’s Shark Bay, the world’s most diverse stromatolite trove.

Previously there were four known chlorophylls made by plants and other photosynthesizing organisms that generate oxygen: a, b, c and d. Chlorophyll a, the standard green type, is found in photosynthesizers from algae to higher plants. It absorbs mostly blue light around 465 nanometers and red light around 665 nanometers (it reflects green light, hence plants look green). Chlorophylls b and c are found in fewer organisms and absorb light in a similar range as chlorophyll a does, but shifted a bit. Chlorophyll d, found in a specific group of cyanobacteria, absorbs the most light at roughly 697 nanometers, a slightly shorter wavelength than the absorption of the new chlorophyll.

While some bacteria make chlorophyll-like pigments that absorb even longer wavelengths of light, these creatures aren’t harnessing light to split water, the step in photosynthesis that generates oxygen. Scientists didn’t think that wavelengths absorbed by chlorophyll f would have enough oomph to split water either, but it turns out they do, says Chen.

“This challenges our conception of the limit of oxygenic photosynthesis,” she says.

The find may also enable scientists to engineer algae that are more efficient producers of oil for biofuels, says algae biologist Krishna Niyogi of the University of California, Berkeley. Microbes bearing the new chlorophyll could soak up rays that most microbes can’t make use of.

There is still much to be learned about the new type of chlorophyll and the organisms that make it, Niyogi says. Chlorophyll f was extracted from the ground-up stromatolites along with a lot of chlorophyll a. It isn’t clear what creature was making chlorophyll f, but evidence points to a filamentous cyanobacterium. This cyanobacterium might use both chlorophylls, or perhaps just f.

Images: 1) Red-shifting cyanobacteria./Science. 2) Shark Bay stromatolites./Wikimedia Commons.

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Plants can think and perform computations, say scientists [Mad Science]

14 Jul
Plants are able to assess their environment by analyzing light, and are able to "remember" light they have experienced recently. By analyzing chemical reactions in leaves, scientists have come to appreciate that plants possess a kind of intelligence. More »