Plants

Subterms

    More stories

    • 113 Shares169 Views

      in Space & Astronomy

      These are the first plants grown in moon dirt

      by

      That’s one small stem for a plant, one giant leap for plant science.

      In a tiny, lab-grown garden, the first seeds ever sown in lunar dirt have sprouted. This small crop, planted in samples returned by Apollo missions, offers hope that astronauts could someday grow their own food on the moon.

      But plants potted in lunar dirt grew more slowly and were scrawnier than others grown in volcanic material from Earth, researchers report May 12 in Communications Biology. That finding suggests that farming on the moon would take a lot more than a green thumb.

      Sign Up For the Latest from Science News

      Headlines and summaries of the latest Science News articles, delivered to your inbox

      Thank you for signing up!

      There was a problem signing you up.

      “Ah! It’s so cool!” says University of Wisconsin–Madison astrobotanist Richard Barker of the experiment.

      “Ever since these samples came back, there’s been botanists that wanted to know what would happen if you grew plants in them,” says Barker, who wasn’t involved in the study. “But everyone knows those precious samples … are priceless, and so you can understand why [NASA was] reluctant to release them.”

      Now, NASA’s upcoming plans to send astronauts back to the moon as part of its Artemis program have offered a new incentive to examine that precious dirt and explore how lunar resources could support long-term missions (SN: 7/15/19).

      The dirt, or regolith, that covers the moon is basically a gardener’s worst nightmare. This fine powder of razor-sharp bits is full of metallic iron, rather than the oxidized kind that is palatable to plants (SN: 9/15/20). It’s also full of tiny glass shards forged by space rocks pelting the moon. What it is not full of is nitrogen, phosphorus or much else plants need to grow. So, even though scientists have gotten pretty good at coaxing plants to grow in fake moon dust made of earthly materials, no one knew whether newborn plants could put down their delicate roots in the real stuff.

      To find out, a trio of researchers at the University of Florida in Gainesville ran experiments with thale cress (Arabidopsis thaliana). This well-studied plant is in the same family as mustards and can grow in just a tiny clod of material. That was key because the researchers had only a little bit of the moon to go around.

      The team planted seeds in tiny pots that each held about a gram of dirt. Four pots were filled with samples returned by Apollo 11, another four with Apollo 12 samples and a final four with dirt from Apollo 17. Another 16 pots were filled with earthly volcanic material used in past experiments to mimic moon dirt. All were grown under LED lights in the lab and watered with a broth of nutrients. 

      Thale cress plants grown for 16 days in volcanic material from Earth (left) looked starkly different compared with seedlings nourished in moon dirt (right). Plants potted in samples returned by the Apollo 11 mission (right, top) fared worse than those planted in Apollo 12 samples (right, middle) or Apollo 17 samples (right, bottom).Tyler Jones, IFAS/UF

      “Nothing really compared to when we first saw the seedlings as they were sprouting in the lunar regolith,” says Anna-Lisa Paul, a plant molecular biologist. “That was a moving experience, to be able to say that we’re watching the very first terrestrial organisms to grow in extraterrestrial materials, ever. And it was amazing. Just amazing.”

      Plants grew in all the pots of lunar dirt, but none grew as well as those cultivated in earthly material. “The healthiest ones were just smaller,” Paul says. The sickliest moon-grown plants were tiny and had purplish pigmentation — a red flag for plant stress. Plants grown in Apollo 11 samples, which had been exposed on the lunar surface the longest, were most stunted.

      Paul and colleagues also inspected the genes in their mini alien Eden. “By seeing what kind of genes are turned on and turned off in response to a stress, that shows you what tools plants are pulling out of their metabolic toolbox to deal with that stress,” she says. All plants grown in moon dirt pulled out genetic tools typically seen in plants struggling with stress from salt, metals or reactive oxygen species (SN: 9/8/21).

      Apollo 11 seedlings had the most severely stressed genetic profile, offering more evidence that regolith exposed to the lunar surface longer — and therefore littered with more impact glass and metallic iron — is more toxic to plants.

      Future space explorers could choose the site for their lunar habitat accordingly. Perhaps lunar dirt could also be modified somehow to make it more comfortable for plants. Or plants could be genetically engineered to feel more at home in alien soil. “We can also choose plants that do better,” Paul says. “Maybe spinach plants, which are very salt-tolerant, would have no trouble growing in lunar regolith.”

      Barker isn’t daunted by the challenges promised by this first attempt at lunar gardening.  “There’s many, many steps and pieces of technology to be developed before humanity can really engage in lunar agriculture,” he says. “But having this particular dataset is really important for those of us that believe it’s possible and important.” More

    • 138 Shares169 Views

      in Heart

      Invasive grasses are taking over the American West’s sea of sagebrush

      by

      No one likes a cheater, especially one that prospers as easily as the grass Bromus tectorum does in the American West. This invasive species is called cheatgrass because it dries out earlier than native plants, shortchanging wildlife and livestock in search of nutritious food.

      Unfortunately for those animals and the crowded-out native plants, cheatgrass and several other invasive annual grasses now dominate one-fifth of the Great Basin, a wide swath of land that includes portions of Oregon, Nevada, Idaho, Utah and California. In 2020, these invasive grasses covered more than 77,000 square kilometers of Great Basin ecosystems, including higher elevation habitats that are now accessible to nonnative plants due to climate change, researchers report November 17 in Diversity and Distributions.

      This invasion of exotic annual grasses is degrading one of North America’s most imperiled biomes: a vast sea of sagebrush shrubs, wildflowers and bunchgrasses where pronghorn and mule deer roam and where ranchers rely on healthy rangelands to raise cattle.

      What’s more, these invasive grasses, which are highly flammable when dry, are also linked to more frequent and larger wildfires. In parts of Idaho’s Snake River Plain that are dominated by cheatgrass, for example, fires now occur every three to five years as opposed to the historical average of 60 to 110 years. From 2000 to 2009, 39 out of 50 of the largest fires in the Great Basin were associated with cheatgrass.

      Sign Up For the Latest from Science News

      Headlines and summaries of the latest Science News articles, delivered to your inbox

      Thank you for signing up!

      There was a problem signing you up.

      To add insult to injury, cheatgrass is more efficient at recolonizing burned areas after a fire than native plants, creating a vicious loop: More cheatgrass causes more fires, and more fires foster more of the weeds. This means that land managers are often behind the curve, trying to keep cheatgrass from spreading to prevent wildfires, while also attempting to restore native plant communities after fires so that the sagebrush ecosystems don’t transition into a monoculture of invasive grasses.

      “We need to get strategic spatially to pinpoint where to protect intact native plant communities rather than constantly chasing the problem,” says Joseph Smith, a rangeland ecology researcher at the University of Montana in Missoula.

      To do that, Smith and his colleagues quantified how much of the Great Basin has transitioned to invasive annual grasses over the last three decades. The researchers used the Rangeland Analysis Platform, or RAP, a remote sensing product powered by Google Earth Engine that estimates the type and percentage of vegetation at a baseball diamond–sized scale.

      While the satellite imagery that RAP relies on can show where annual grasses turn brown in late spring in the West or where perennial plants stay green longer into the summer, the technology can’t delineate between native and nonnative plants. So researchers cross-checked RAP data with on-the-ground vegetation surveys collected through the U.S. Bureau of Land Management’s assessment, inventory and monitoring strategy.

      Invasive annual grasses have increased eightfold in area in the Great Basin region since 1990, the team found. Smith and colleagues estimate that areas dominated by the grasses have grown more than 2,300 square kilometers annually, a rate of take-over proportionally greater than recent deforestation of the Amazon rainforest.

      Perhaps most alarmingly, the team found that annual grasses, most of which are invasive, are steadily moving into higher elevations previously thought to be at minimal risk of invasion (SN: 10/3/14). Invasive annual grasses don’t tolerate cold, snowy winters as well as native perennial plants. But as a result of climate change, winters are trending more mild in the Great Basin and summers more arid. While perennial plants are struggling to survive the hot, dry months, invasive grass seeds simply lie dormant and wait for fall rains.

      “In a lot of ways, invasive grasses just do an end run around perennials. They don’t have to deal with the harshest effects of climate change because of their different life cycle,” Smith explains.

      Though the scale of the problem can seem overwhelming, free remote sensing technology like RAP may help land managers better target efforts to slow the spread of these invasive grasses and explore their connection to wildfires. Smith, for instance, is now researching how mapping annual grasses in the spring might help forecast summer wildfires.

      “If we don’t know where the problem is, then we don’t know where to focus solutions,” says Bethany Bradley, an invasion ecologist and biogeographer at the University of Massachusetts Amherst who wasn’t involved in the research. “Mapping invasive grasses can certainly help people stop the grass-fire cycle by knowing where to treat them with herbicides.” More