Rice Gene Digs Deep To Triple Yields In Drought

ORIGINAL: Asian Scientist
By Science and Development Network | Featured Research
August 6, 2013

Japanese researchers have identified a gene that triples the yield of rice during droughts by giving rice plants deeper roots.

Asian Scientist (Aug. 6, 2013) - A gene that gives rice plants deeper roots can triple yields during droughts, according to Japanese researchers writing in Nature Genetics this week (4 August).

Rice is a staple food for nearly half of the world’s population, but is also particularly susceptible to drought owing to its shallow roots, researchers say.

The new study shows that by pointing roots down instead of sideways, the Deeper Rooting 1 (DRO1) gene results in roots that are nearly twice as deep as those of standard rice varieties.


“If rice adapts to or avoids drought conditions using deeper roots, it can get water and nutrients from the deep soil layers,” says the study’s lead author Yusaku Uga, a researcher with Japan’s National Institute of Agrobiological Sciences.

Uga and his team found that in moderate drought conditions, the yield of rice with DRO1 was double that of the shallow-rooted rice variety. Under severe drought conditions, this increased to 3.6 times greater.

“The most important point is that we had rice grains produced under drought conditions,” says Uga.

“When rice crops just tolerate drought, they cannot get water and nutrients, resulting in a kind of survival mode.”

The DRO1 gene occurs naturally in more than 60 rice varieties. For the study, the research team crossbred a rice variety carrying DRO1 with a shallow-rooted variety and then bred the offspring together to produce a rice crop in which DRO1 was uniformly present.

The International Rice Research Institute (IRRI) estimates that an additional 8-10 million tonnes of rice will be needed each year to keep rice prices affordable at around US$300 per tonne. Finding a drought-resistant variety of rice may be key to attaining this goal, according to researchers.

“Drought is the most widespread and damaging of all environmental stresses,” says Sophie Clayton, head of communications at IRRI.

“In some states in India, severe drought can cause as much as 40 per cent yield loss [in rice crops]. Moreover, with the onset of climate change, droughts may become more frequent and more severe.”

The article can be found at: Uga et al. (2013) Control Of Root System Architecture By DEEPER ROOTING 1 Increases Rice Yield Under Drought Conditions.

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Source: Science and Development Network; Photo: IRRI.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

Artificial Photosynthesis for Splitting Water Reaches One-Volt Milestone

ORIGINAL: IEEE Spectrum
By Dexter Johnson
Posted 21 Aug 2013 | 0:53 GMT

Image: HyperSolar

Almost 18 months ago, HyperSolar, Inc., a company based in Santa Barbara, CA, unveiled its ambitious plans for artificial photosynthesis. The announcement promised “the world’s first nanotechnology-based, zero-carbon process for the production of renewable hydrogen and natural gas.” The company was so confident that, two months later, it promised to publicly chronicle its progress toward the lofty goal.

Other companies have tried—and failed—to find an artificial photosynthesis process that can split water into hydrogen and oxygen and do it economically. Around the same time that HyperSolar promised to chronicle their efforts, Sun Catalytix determined that its process for splitting water just didn’t make economic sense when they crunched the numbers.

In the journal Nature, the maker of Sun Catalytix’s prototype explained the dreary economics:

“Hydrogen from a solar panel and electrolysis unit can currently be made for about US$7 per kilogram, the firm estimates; the artificial leaf would come in at US$6.50. (It costs just $1-2 to make a kilogram of hydrogen from fossil fuels.) With the prices of solar cells dropping all the time, the firm is not going to make a heavy investment that's unlikely to pay off. Instead, it is looking at cheaper designs—but these require yet-to-be-invented semiconductor materials.”

When I didn’t hear any updates from HyperSolar on how its grand project was progressing this year, I began to suspect that they had encountered these same numbers and had a second thought. I guess I was wrong—the company just sent out a press release detailing its success in achieving the 1-volt milestone. To date inexpensive silicon solar cells are the most inexpensive and abundant, but their 0.7 volt per cell is not enough to split water.

HyperSolar's 1 volt per cell is still short of the 1.5 volts realistically needed to split water into hydrogen and oxygen, but the 1 volt number does represent a steady progression, according to the company. HyperSolar managed to increase the voltage from 0.2 volts eight months ago to .75 volts three months ago. At that rate of increase, one could expect that the company could achieve the 1.5 volts in another six months.

“Our cutting-edge research program at the University of California Santa Barbara led by Dr. Syed Mubeen Hussaini continues to make impressive progress,” stated Tim Young, CEO of HyperSolar, in the press release. “The 1.0 volt milestone is very exciting in that it provides us with a clear and encouraging roadmap to reach the 1.5 volts needed for water splitting. The semi-conductor materials used are very inexpensive, which gives us confidence that a low cost system is possible. The process to make this novel solar cell is equally exciting in that it is a simple solutions-based chemistry process. It does not require conventional expensive semiconductor processes and facilities. It was literally made in a beaker.”

The key to HyperSolar’s proposed technology will be a nanoparticle made from low-cost semiconductor materials. In the company’s original roadmap for milestones, they were supposed to design this nanoparticle within the first year. It’s not clear from this press release whether that design has been settled upon, except to explain that each nanoparticle: “is a complete hydrogen generator that contains a novel high voltage solar cell bonded to chemical catalysts by a proprietary encapsulation coating.”

It is interesting that the company is providing key metrics for determining whether the system will work, but it would be good to have a better sense of where they are in developing the nanoparticle that forms the basis of this technology.

Unleashing oxygen ‘Superlattice’ structure could give a huge boost to oxygen reaction in fuel cells, increasing their power potential.

ORIGINAL: MIT

David L. Chandler, MIT News Office

April 30, 2013

Professor Bilge Yildiz (left) and graduate student Yan Chen stand in front of the scanning tunneling microscope used for their research. PHOTO COURTESY OF BILGE YILDIZ

New research at MIT could dramatically improve the efficiency of fuel cells, which are considered a promising alternative to batteries for powering everything from electronic devices to cars and homes.

Fuel cells make electricity by combining hydrogen, or hydrocarbon fuels, with oxygen. But the most efficient types, called solid oxide fuel cells (SOFC), have drawbacks that have limited their usefulness — including operating temperatures above 700 degrees Celsius (roughly 1300 degrees Fahrenheit). Now, MIT researchers have unraveled the properties of a promising alternative material structure for a key component of these devices.

The new structure, a “superlattice” of two compounds interleaved at a tiny scale, could serve as one of the two electrodes in the fuel cell. The complex material, discovered about six years ago and known as LSC113/214, is composed of two oxides of the elements lanthanum, strontium and cobalt. While one of the oxides was already known as an especially good material for such electrodes, the combination of the two is far more potent in promoting oxygen reduction than either oxide alone. 

The interfaces between these two oxides were thought to be the key. But until now, no one had been able to observe the LSC113/214 interface properties in operation, at sufficiently high resolution, to figure out why it worked so well.

The MIT team used a scanning tunneling microscope (STM) to study the electrical activity of a superlattice material composed of two different compounds of the elements strontium, lanthanum and cobalt. At bottom, a diagram of how they "sliced" the material on an angle to expose wider bands of the thin layers of material. The center two images show the resulting measurements of the surface topography of the material, and the activity of electrons moving through it. At top, a diagram of the molecular structures of the two compounds. 
GRAPHIC COURTESY OF CHEN ET AL

Oxygen reduction is one of two main reactions in a fuel cell, and the one that has limited their overall performance — so finding improved materials for that reaction could be a key advance for fuel cells, the researchers say. The new findings are published in the journal Advanced Energy Materials in a paper co-authored by graduate student Yan Chen, professors Harry Tuller and Bilge Yildiz, and three other researchers at MIT.

Yildiz, an associate professor of nuclear science and engineering, says LSC113/214 has been “a singular example” of a material with extremely high reactivity to oxygen reduction; the new results explaining why it works so well could lead to further optimization or the discovery of other materials that might perform even better.

The best of both

The key to the material’s performance, she explains, is the marriage of complementary qualities from its two constituents. One of the oxides allows superior conduction and transfer of electrons, while the other excels at holding onto oxygen atoms; to perform well as a fuel cell’s cathode — one of its two electrodes — a material needs to have both qualities. 

The close proximity of the two materials in this superlattice causes them to “borrow” one another’s attributes, the MIT team found. The result is a material whose reactivity exceeds that of the best materials currently used in fuel cells, Yildiz says: “It’s the best of the two worlds.”

Now that the MIT team has analyzed LSC113/214, it may be possible to discover even better materials by conducting systematic searches, Yildiz says; the team is now working on that. “If we can crack this problem, then we can make great strides in improving the performance,” adds Tuller, a professor of ceramics and electronic materials in MIT’s Department of Materials Science and Engineering.

Unique tool enables observations

The finding was made possible by instrumentation developed in Yildiz’s laboratory at MIT for observation of electron-transfer properties on surfaces: The instrument, a modified scanning tunneling microscope (STM), can observe materials at high temperatures and in an oxygen-rich environment — “representative of the operating conditions of a fuel-cell cathode,” Yildiz says. This high-temperature phenomenon would not have been detectable with conventional methods.

Tuller describes the superlattice as a “layer cake” of the two different oxides. But these layers are vanishingly thin. To overcome this, the team “sliced” the layers on an extreme angle, exposing much wider surfaces of each. “That magnifies the layers by a hundredfold,” Tuller says.

That slicing is done using a focused ion beam, Chen explains, to expose the interface in a way that the STM can observe more easily at high temperature.

The researchers hope that with this new knowledge, it will be possible to make rapid progress in the search for better electrode materials, helping make fuel cells practical for a wide range of energy applications, from powering homes to powering mobile devices. 

John Kilner, a professor of energy materials at Imperial College, London, who was not involved in this project, calls this “a very elegant set of experiments that contributes a great deal toward our understanding of the very complex problem of oxygen surface exchange.”

Kilner adds, “It waits to be seen if we can capitalize on this knowledge to aid in the construction of practical devices, but it opens up the possibility of engineering new structures with enhanced performance at low temperatures.”

The work was supported by the U.S. Department of Energy’s Basic Energy Sciences Program.

MIT's 2013 Top 10 Breakthrough Technologies - 2: Ultra-Efficient Solar Power

ORIGINAL: Tech Review

By Mike Orcutt

April 23, 2013

Doubling the efficiency of solar devices would completely change the economics of renewable energy. Here is a design that just might make it possible.

Harry Atwater thinks his lab can make an affordable device that produces more than twice the solar power generated by today’s panels. The feat is possible, says the Caltech professor of materials science and applied physics, because of recent advances in the ability to manipulate light at a very small scale.

Solar panels on the market today consist of cells made from a single semiconducting material, usually silicon. Since the material absorbs only a narrow band of the solar spectrum, much of sunlight’s energy is lost as heat: these panels typically convert less than 20 percent of that energy into electricity. But the device that ­Atwater and his colleagues have in mind would have an efficiency of at least 50 percent. It would use a design that efficiently splits sunlight, as a prism does, into six to eight component wavelengths—each one of which produces a different color of light. Each color would then be dispersed to a cell made of a semiconductor that can absorb it.

Atwater’s team is working on three designs. In one (see illustration), for which the group has made a prototype, sunlight is collected by a reflective metal trough and directed at a specific angle into a structure made of a transparent insulating material. Coating the outside of the transparent structure are multiple solar cells, each made from one of six to eight different semiconductors. Once light enters the material, it encounters a series of thin optical filters. Each one allows a single color to pass through to illuminate a cell that can absorb it; the remaining colors are reflected toward other filters designed to let them through.

Another design would employ nanoscale optical filters that could filter light coming from all angles. And a third would use a hologram instead of filters to split the spectrum. While the designs are different, the basic idea is the same: combine conventionally designed cells with optical techniques to efficiently harness sunlight’s broad spectrum and waste much less of its energy.

It’s not yet clear which design will offer the best performance, says Atwater. But the devices envisioned would be less complex than many electronics on the market today, he says, which makes him confident that once a compelling prototype is fabricated and optimized, it could be commercialized in a practical way.

Achieving ultrahigh efficiency in solar designs should be a primary goal of the industry, argues Atwater, since it’s now “the best lever we have” for reducing the cost of solar power. That’s because prices for solar panels have plummeted over the past few years, so continuing to focus on making them less expensive would have little impact on the overall cost of a solar power system; expenses related to things like wiring, land, permitting, and labor now make up the vast majority of that cost. Making modules more efficient would mean that fewer panels would be needed to produce the same amount of power, so the costs of hardware and installation could be greatly reduced. “Within a few years,” Atwater says, “there won’t be any point to working on technology that has efficiency that’s less than 20 percent.”