
Quantum Dots Shift Sunlight's Spectrum to Speed Plant Growth - jonbaer
https://spectrum.ieee.org/view-from-the-valley/at-work/start-ups/quantum-dots-shift-sunlights-spectrum-to-speed-plant-growth
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reportingsjr
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](https://en.wikipedia.org/wiki/Photosynthetic_efficiency)

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xdze2
now I am wondering, why more efficient plants have not evolved by natural
selection ?

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colechristensen
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.

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superkuh
1200sq ft is currently $3600.
[https://www.ubiqd.shop/collections/frontpage/products/ubigro...](https://www.ubiqd.shop/collections/frontpage/products/ubigro-600?variant=31115055628382)

Also, whitepaper/case studies:
[https://img1.wsimg.com/blobby/go/e91a4987-3726-410f-8e4a-95c...](https://img1.wsimg.com/blobby/go/e91a4987-3726-410f-8e4a-95cd1495a184/downloads/UbiGro%20White%20Paper_All_FullColor_EB050120.pdf?ver=1589220731742)

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joss82
White paper tldr: between +5% (cannabis) and +20% yield (tomatoes).

This is huge.

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082349872349872
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.

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adrianN
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...](https://www.lowtechmagazine.com/2015/12/reinventing-the-
greenhouse.html)

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

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

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

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TomMarius
No evolution needs to happen in a controlled environment.

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welfare
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?)

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

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spooneyluv
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.

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

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sp332
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%.

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sandworm101
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.

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lymeeducator
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?

