Quantum Dots Shift Sunlight's Spectrum to Speed Plant Growth | Hacker News Reader

Quantum Dots Shift Sunlight's Spectrum to Speed Plant Growth

spectrum.ieee.org

95 pointsjonbaer24 comments

This isn't too surprising. It's the same improvements people have been expecting from using solar panels and LEDs to grow plants.

Since numbers and mechanisms aren't really explained I'll drop some numbers here: ~50% of incoming sunlight energy is lost to plants just by falling outside of the range that chlorophyll can absorb (400-700nm). ~25% of the light energy that is absorbed, is lost by dropping the higher energy wavelength light (the 400nm/blueish end) to the 700nm level needed for the rest of the process.

Just from these two losses you're at 37.5% efficiency, so converting to better wavelength light either by quantum dot or solar panels/LEDs has a massive impact on crops grown per area, particularly in higher latitudes.

Just for reference, the most efficient plants (heavily bred/modified crops) are in the range of 1-2% efficient for the whole photosynthetic process.

https://en.wikipedia.org/wiki/Photosynthetic_efficiency

now I am wondering, why more efficient plants have not evolved by natural selection ?

There must be a pressure some pressure that gives enough advantage/disadvantage. Evolution isn’t about improvement just who survives to reproduce. Most improvements also come at some cost.

I’ve always wondered that too. Maybe evolution is stuck in a local optimum there.

1200sq ft is currently $3600. https://www.ubiqd.shop/collections/frontpage/products/ubigro...

Also, whitepaper/case studies: https://img1.wsimg.com/blobby/go/e91a4987-3726-410f-8e4a-95c...

White paper tldr: between +5% (cannabis) and +20% yield (tomatoes).

This is huge.

A long time ago I was looking at artificial chlorophyll. About all I remember is that in comparison to inorganics, that stuff's already super wideband and detuned.

(OP is definitely a cool approach, anyone know anything about last year's progress in artificial chlorophylls?)

Edit: as to the effects of speeding up plant growth, we've already had several instances in history where more intensive agricultual techniques have improved crop yields, some of which were by increasing number of harvests/season.

This is pretty awesome. A lot of vegetables are grown in greenhouses, but traditional greenhouses are quite energy intensive. Anything that reduces the need for greenhouse area could save quite a bit of carbon. Paired with techniques [1] to reduce the amount of heating needed, this could be a real game changer.

[1] https://www.lowtechmagazine.com/2015/12/reinventing-the-gree...

Maybe. The question is: Are QDs building energy efficient? Or does it require high-energy chemical reaction.

I wonder what would be the side-effects of speeding up plant growth.

You could probably distribute the light among a larger number of plants (think plants stacked on a shelf, or on a tilted surface), so you grow more instead of faster.

IIRC there were some studies saying that higher CO2 in the atmosphere leads to better growth but lower nutritional value so that's one possible side-effect.

I think you have a point. There's no free lunch in evolution based systems, at least that's my perception.

No evolution needs to happen in a controlled environment.

Plants have evolved to adapt to a certain environment, and if we change those parameters to promote a certain behaviour (e.g. higher yield) then most likely it comes at a cost (e.g. is the produce less nutritious?)

I'm curious to know if there's a limit to selecting plants cultivars. What should we optimize for? Vitamins, minerals, proteins, glucids, lipids, fibers or other macromolecules? Should we allow some sacrifice in taste, appearance, yield, resistance, conservation?

Why does the change have to be negative for humans? The products could just as well become more nutritious.

Evolution does not optimize to global maxima, it prefers local maximas. The path it has taken so far is also pretty convoluted.

It's pretty clear that sunlight isn't the absolute best spectrum for growing plants, so we know plants haven't evolved optimally to make use of the sun's spectrum as-is. I think a local max is the right idea. this tech is shortcutting that evolution and providing a better spectrum without using electricity, like LEDs would.

Would this make up the difference for the dimmer light on Mars?

The white paper shows an increase of 20%, but solar irradiance on Mars is about 60% of what you can get on Earth (below the atmosphere). So it would be equivalent to 60% * 120% = 72%.

60% is the total flux hitting the planet. Due to dust, the amount of light hitting the surface is generally much lower. During a dust storm, it can be as dark as an earth night.

apparently the company is working with NASA for crop growth in Lunar/Martian subterranean grow modules https://www.prnewswire.com/news-releases/nasa-awards-ubiqd-s...

I think it's important to measure the plants entire molecular composition because uncertainty about what adaptations are skipped from growing across a broader spectrum of light?

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