Mutant Corn Could Be The Future Of Agriculture

In America, corn syrup is king, and real sugar hovers somewhere around prince status. We’re addicted to corn, and corn, in turn, is addicted to nitrogen. A long time ago, people figured out that by rotating crops, the soil will stay nutrient-rich, which helps to an extent by retaining nitrogen. Then we figured out how to make nitrogen fertilizer, and through its use we essentially doubled the average crop yield over the last hundred years or so.

The aerial roots of the Sierra Mixe corn stalk help the plant produce its own nitrogen. Image via Wikimedia Commons

Not all plants need extra nitrogen. Legumes like beans and soybeans are able to make their own. But corn definitely needs nitrogen. In the 1980s, the now-chief of agriculture for Mars, Inc. Howard-Yana Shapiro went to Mexico, corn capital of the world, looking for new kinds of corn. He found one in southern Mexico, in the Mixes District of Oaxaca. Not only was this corn taller than American corn by several feet, it somehow grew to these dizzying heights in terrible soil.

Shapiro thought the corn’s success might have something to do with the aerial, finger-like roots protruding from the cornstalk. Decades later, it turns out he was right. Researchers at UC Davis have proven that those aerial roots allow the plant to grab nitrogen out of the air through a symbiotic relationship with bacteria in that clear, syrupy mucus. The process is called nitrogen fixation.

Nitrogen Fixing is a Bit Broken

So if we already have nitrogen fertilizer, why even look for plants that do it themselves? The Haber-Bosch fertilizer-making process, which is an artificial form of nitrogen fixation, does make barren soil less of a factor. But that extra nitrogen in ammonia-based fertilizer tends to run off into nearby streams and lakes, making its use an environmental hazard. And the process of creating ammonia for fertilizer involves fossil fuels, uses a lot of energy, and produces greenhouse gases to boot. All in all, it’s a horrible thing to do to the environment for the sake of agriculture. But with so many people to feed, what else is there to do?

The Haber-Bosch process illustrated. Image via Wikimedia Commons

Over the last decade, the UC Davis researchers use DNA sequencing to determine that the mucus on the Sierra Mixe variety of the plant provides microbes to the corn, which give it both sugars to eat and a layer of protection from oxygen. They believe that the plants get 30-80% of their nitrogen this way. The researchers also proved that the microbes do in fact belong to nitrogen-fixing families and are similar to those found in legumes. Most impressively, they were able to transplant Sierra Mixe corn to both Davis, California and Madison, Wisconsin, and have it grow successfully, proving that the nitrogen-fixing trick isn’t limited to the corn’s home turf. Now they are working to identify the genes that produce the aerial roots.

One Step in a Longer Journey of Progress

We probably won’t be switching over to Sierra Mixe corn anytime soon, however. It takes eight months to mature, which is much too slow for American appetites used to a three-month maturation period. If we can figure out how to make other plants do their own nitrogen fixation, who knows how far we could go? It seems likely that more people would accept a superpower grafted from a corn cousin instead of trying to use CRISPR to grant self-nitrogen fixation, as studies have shown a distrust of genetically modified foods.

The issue of intellectual property rights could be a problem, but the researchers started on the right foot with the Mexican government by putting legal agreements in place that ensure the Sierra Mixe community benefits from research and possible commercialization. We can’t wait to see what they’re able to do. If they’re unable to transplant the power of self-fixation to other plants, then perhaps there’s hope for improving the Haber-Bosch process.

First Light: The Story Of The Laser

Lasers are such a fundamental piece of technology today that we hardly notice them. So cheap that they can be given away as toys and so versatile that they make everything from DVD players to corneal surgery a reality, lasers are one of the building blocks of the modern world. Yet lasers were once the exclusive province of physicists, laboring over expansive and expensive experimental setups that seemed more the stuff of science fiction than workhouse tool of communications and so many other fields. The laser has been wildly successful, and the story of its development is an intriguing tale of observation, perseverance, and the importance of keeping good notes.

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Cheap And Easy Magnetic DNA Separation Method Needs Your Help

When you consider that almost every single cell in your body has more than a meter of DNA coiled up inside its nucleus, it seems like it should be pretty easy to get some to study. But with all the other cellular gunk in a crude preparation, DNA can be quite hard to isolate. That’s where this cheap and easy magnetic DNA separation method comes in. If it can be optimized and tested with some help from the citizen science community.

Commercial DNA separation methods generally involve mixing silica beads into crude cell fractions; the DNA preferentially binds to the silica, making it possible to mechanically separate it from the rest of the cellular junk. But rather than using a centrifuge to isolate the DNA, [Justin] from The Thought Emporium figured that magnets might do a better job. It’s not a new idea — biotech companies offer magnetic separation beads commercially, but at too steep a price for [Justin]’s budget. His hack comes from making magnetite particles from common iron compounds like PCB etchant and moss killer, and household ammonia cleaner. The magnetite particles are then coated with sodium silicate solution, also known as waterglass. The silica coating should allow the beads to bind to DNA, with the magnetic core taking care of separation.

[Justin] was in the process of testing his method when he lost access to the needed instruments, so he’s appealing to the larger science community for help optimizing his technique. Based on his track record of success in fields ranging from satellite tracking to graphene production, we’ll bet he’ll nail this one too.

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Using Vacuum Tubes As Immersion Heaters

Fellow Hackaday writer [Ethan Zonca] was doing a little bit of woodworking recently and decided to test ammonia fuming on a small piece of oak. Yes, this means discoloring wood with ammonia vapor, and it’s a real technique. [Ethan] wanted to increase the rate of evaporation of his ammonia solution and decided to make an immersion heater. Out of a vacuum tube.

This is a non-optimal solution to the problem of heating a solution of ammonia – already a bad idea unless you have a fume hood – but it gets better. The vacuum tube was slightly cracked, something easily fixed with a bit of silicone sealant. This was then immersed in an ammonia solution, wired up to a driver board and controlled by a homebrew PID controller. If it’s stupid and it works, it’s not stupid.

After getting the ammonia solution up to 30° C, a noxious cloud of ammonia seeped into a piece of oak. This was left overnight, and the result is something that looks like old barn wood, and looks great after some linseed oil is rubbed into it. This is only a test run for fuming an entire desktop this spring, and while that’s a project that will require a real heater (and doing it outside), it’s still a great demonstration of lateral thinking and great woodworking techniques.

Gas Sensor Suite Built With Gadgeteer Modules


[Blake] just finished a gas sensor suite built from Gadgeteer parts. The three sensors are the cylindrical towers along the left hand side of the assembly. The one at the top (with the orange ring) is an alcohol sensor. The middle one senses ammonia and the lower sensor measures air quality. Also rolled into the mix are temperature and humidity sensors.

You can collect a lot of data with this type of setup. To keep it organized [Blake] used the ThingSpeak interface. Using the NIC in the upper right he uploads the measurements for real-time graphing. The setup is explained in detail in the video after the break, including a test with some cleaning ammonia.

We haven’t tried out the Gadgeteer system for ourselves yet. But you’ve got to admit that the ribbon cable connector system the family of parts uses really helps to keep a rather complicated setup like this one nice and tidy.

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