Posts Tagged ‘agriculture’

Zinnias such as this one were among the first flowers to be grown on the International Space Station.

Researchers on the International Space Station are growing plants in systems that may one day sustain astronauts traveling far across the solar system and beyond.

Vibrant orange flowers crown a leafy green stem. The plant is surrounded by many just like it, growing in an artificially lit greenhouse about the size of a laboratory vent hood. On Earth, these zinnias, colorful members of the daisy family, probably wouldn’t seem so extraordinary. But these blooms are literally out of this world. Housed on the International Space Station (ISS), orbiting 381 kilometers above Earth, they are among the first flowers grown in space and set the stage for the cultivation of all sorts of plants even farther from humanity’s home planet.

Coaxing this little flower to bloom wasn’t easy, Gioia Massa, a plant biologist at NASA’s Kennedy Space Center in Florida, tells The Scientist. “Microgravity changes the way we grow plants.” With limited gravitational tug on them, plants aren’t sure which way to send their roots or shoots. They can easily dry out, too. In space, air and water don’t mix the way they do on Earth—liquid droplets glom together into large blobs that float about, instead of staying at the roots.

Massa is part of a group of scientists trying to overcome those challenges with a benchtop greenhouse called the Vegetable Production System, or Veggie. The system is a prototype for much larger greenhouses that could one day sustain astronauts on journeys to explore Mars. “As we’re looking to go deeper into space, we’re going to need ways to support astronaut crews nutritionally and cut costs financially,” says Matthew Romeyn, a long-duration food production scientist at Kennedy Space Center. “It’s a lot cheaper to send seeds than prepackaged food.”

In March 2014, Massa and colleagues developed “plant pillows”—small bags with fabric surfaces that contained a bit of soil and fertilizer in which to plant seeds. The bags sat atop a reservoir designed to wick water to the plants’ roots when needed (Open Agriculture, 2:33-41, 2017). At first, the ISS’s pillow-grown zinnias were getting too much water and turning moldy. After the crew ramped up the speed of Veggie’s fans, the flowers started drying out—an issue relayed to the scientists on the ground in 2015 by astronaut Scott Kelly, who took a special interest in the zinnias. Kelly suggested the astronauts water the plants by hand, just like a gardener would on Earth. A little injection of water into the pillows here and there, and the plants perked right up, Massa says.

With the zinnias growing happily, the astronauts began cultivating other flora, including cabbage, lettuce, and microgreens—shoots of salad vegetables—that they used to wrap their burgers and even to make imitation lobster rolls. The gardening helped to boost the astronauts’ diets, and also, anecdotally, brought them joy. “We’re just starting to study the psychological benefits of plants in space,” Massa says, noting that gardening has been shown to relieve stress. “If we’re going to have this opportunity available for longer-term missions, we have to start now.”

The team is currently working to make the greenhouses less dependent on people, as tending to plants during space missions might take astronauts away from more-critical tasks, Massa says. The researchers recently developed Veggie PONDS (Passive Orbital Nutrient Delivery System) with help from Techshot and Tupperware Brands Corporation. This system still uses absorbent mats to wick water to plants’ seeds and roots, but does so more consistently by evenly distributing the moisture. As a result, the crew shouldn’t have to keep such a close eye on the vegetation, and should be able to grow hard-to-cultivate garden plants, such as tomatoes and peppers. Time will tell. NASA sent Veggie PONDS to the ISS this past March, and astronauts are just now starting to compare the new system’s capabilities to those of Veggie.

“What they are doing on the ISS is really neat,” says astronomer Ed Guinan of the University of Pennsylvania. If astronauts are going to venture into deep space and be able to feed themselves, then they need to know how plants grow in environments other than Earth, and which grow best. The projects on the ISS will help answer those questions, he says. Guinan was so inspired by the ISS greenhouses he started his own project in 2017 studying how plants would grow in the soil of Mars—a likely future destination for manned space exploration. He ordered soil with characteristics of Martian dirt and told students in his astrobiology course, “You’re on Mars, there’s a colony there, and it’s your job to feed them.” Most of the students worked to grow nutritious plants, such as kale and other leafy greens, though one tried hops, a key ingredient in beer making. The hops, along with some of the other greens, grew well, Guinan reported at the American Astronomical Society meeting in January.

Yet, if and when astronauts go to Mars, they probably won’t be using the Red Planet’s dirt to grow food, notes Gene Giacomelli, a horticultural engineer at the University of Arizona. There are toxic chemicals called perchlorates to contend with, among other challenges, making it more probable that a Martian greenhouse will operate on hydroponics, similar to the systems being tested on the ISS. “The idea is to simplify things,” says Giacomelli, who has sought to design just such a greenhouse. “If you think about Martian dirt, we know very little about it—so do I trust it is going to be able to feed me, or do I take a system I know will feed me?”

For the past 10 years, Giacomelli has been working with others on a project, conceived by now-deceased business owner Phil Sadler, to build a self-regulating greenhouse that could support a crew of astronauts. This is not a benchtop system like you find on the space station, but a 5.5-meter-long, 2-meter-diameter cylinder that unfurls into an expansive greenhouse with tightly controlled circulation of air and water. The goal of the project, which was suspended in December due to lack of funding, was to show that the lab-size greenhouse could truly sustain astronauts. The greenhouse was only partially successful; the team calculated that a single cylinder would provide plenty of fresh drinking water, but would produce less than half the daily oxygen and calories an astronaut would need to survive a space mission. Though the project is on hold, Giacomelli says he hopes it will one day continue.

This kind of work, both here and on the ISS, is essential to someday sustaining astronauts in deep space, Giacomelli says. And, if researchers can figure out how to make such hydroponic systems efficient and waste-free, he notes, “the heck with Mars and the moon, we could bring that technology back to Earth.”


Synthetic nanoparticles used to fight cancer could also heal sickly plants.

The particles, called liposomes, are nanosized, spherical pouches that can deliver drugs to specific parts of the body (SN: 12/16/06, p. 398). Now, researchers have filled these tiny care packages with fertilizing nutrients. The new liposomes, described online May 17 in Scientific Reports, soak into plant leaves more easily than naked nutrients. That allows the nanoparticles to give malnourished crops a more potent pick-me-up than the free-floating molecules in ordinary nutrient spray.

Each liposome is a hollow sphere about 100 nanometers across, and is made of fatty molecules extracted from soybean plants. Once a plant leaf absorbs these nanoparticles, the liposomes spread to cells in the plant’s other leaves and its roots, where the fatty envelopes break down and release their molecular cargo.

Researchers first exposed tomato plants to either liposomes packed with a rare earth metal called europium, or free-floating europium molecules. Europium doesn’t naturally exist in plants or soil, so it’s easy to trace how much of this element plants soaked up after treatment. Three days after exposure, plants treated with liposomes had absorbed up to 33 percent of the nanoparticles. Plants exposed to free-floating europium took in less than 0.1 percent of the molecules

The researchers then spritzed iron- and magnesium-deficient tomato plants with either a standard spray containing iron and magnesium, or a solution containing liposomes packed with those nutrients. Two weeks later, the leaves on plants treated with free-floating nutrients were still tinged yellow and curled. Plants that received liposome treatment sported healthy, green leaves.

Avi Schroeder, a chemical engineer at the Israel Institute of Technology in Haifa, and colleagues don’t know exactly why liposomes are more palatable to plants than plain nutrients. But sprays that contain nutrient-loaded liposomes could help farmers rejuvenate frail plants more efficiently than existing mixtures, Schroeder says.

Liposome-based spray would need to be tested on a variety of vegetation before it could enter widespread use, says Ramesh Raliya, a nanobiotechnology researcher at Washington University in St. Louis not involved in the work. That’s because the pores on leaves where liposomes are assumed to enter plants can range from 50 to 150 nanometers across. If a plant’s pores are smaller than 100 nanometers, the liposomes can’t squeeze inside.

Mariya Khodakovskaya, a biologist at the University of Arkansas at Little Rock, is wary of the potential cost of this new technique. Fashioning liposomes is expensive. That’s not a problem for making liposome-based medication, which requires only a small amount of nanoparticles. But for any new agricultural practice to take root, she says, “it has to be massive, and it has to be cheap.”

A. Karny et al. Therapeutic nanoparticles penetrate leaves and deliver nutrients to agricultural crops. Scientific Reports. Published online May 17, 2018. doi: 10.1038/s41598-018-25197-y.

Pod shatter in oilseed rape – problem for farmers worldwide.

Breeding temperature-resilient crops is an “achievable dream” in one of the most important species of commercially-cultivated plants, according to a new study.

The vision of crop improvement in the face of climate change is outlined in research by the John Innes Centre which establishes a genetic link between increased temperature and the problem of “pod shatter” (premature seed dispersal) in oilseed rape.

Research by the team led by Dr Vinod Kumar and Professor Lars Østergaard, reveals that pod shatter is enhanced at higher temperature across diverse species in the Brassicaceae family which also includes cauliflower, broccoli and kale.

This new understanding brings a step closer the prospect of creating crops that are better adapted to warmer temperatures a step closer.

Dr Vinod Kumar, a co-author of the paper explained the significance of the findings:

“It’s almost as if there is a thermostat that controls seed dispersal, or pod shatter. As we learn how it works, we could in the future ‘rewire’ it so seed dispersal does not happen at the same pace at higher temperatures

“This piece of the puzzle, coupled with the use of advanced genetic tools means that developing temperature-resilient crops becomes an achievable dream.”

Controlling seed dispersal, or “pod shatter” is a major issue for farmers of oilseed rape worldwide, who lose between 15-20% of yield on average per year due to prematurely dispersed seeds lost in the field.

The study set out to find out if temperature increases had a direct influence on pod shatter in oilseed rape, and how this is controlled by genetics.

“Over the last two decades, scientists have identified the genes that control pod shatter. However, it is not until now that we begin to understand how their activity is affected by the environment, and in this case temperature,” explained Professor Lars Østergaard.

To study the effects of temperature on seed dispersal, Dr Xinran Li, a postdoctoral researcher, monitored fruit development in Arabidopsis, a model plant related to the important Brassicaceae crops, at three different temperatures 17, 22 and 27 degrees centigrade.

This showed that stiffening of the cell wall at the tissue where pod shatter takes place is enhanced by increasing temperature leading to accelerated seed dispersal.

Dr. Li demonstrated that this was true not only for Arabidopsis, but across the Brassicaceae family, including oilseed rape.

The team went on to establish the genetic mechanism which organises the plant response to higher temperatures. Previous studies have shown that pod shatter is controlled by a gene called INDEHISCENT (IND). This study reveals that IND is under the control of a thermo-sensory mechanism in which a histone called H2A.Z is a key player.

The report concludes: “Our findings introduce an environmental factor to the current knowledge, which provide alternative avenues for crop improvement in the face of climate change.”

The paper Temperature modulates tissue-specification programme to control fruit dehiscence in Brassicaceae which appears in the journal Molecular Plant also identifies the genetic pathways behind the temperature sensing mechanism which coordinates the crop’s response to rises in temperature.

Temperature modulates tissue-specification program to control fruit dehiscence in Brassicaceae: authors Xin-Ran Li, Joyita Deb, S. Vinod Kumar and Lars Østergaard.

Read the full report and paper here: