Reddit reviews Quantum Mechanics for Scientists and Engineers

As you're an engineer, Quantum Mechanics for Scientists and Engineers might be of interest. It's written by a EE professor at Stanford.

A potentially nice optional feature of this is that Stanford offers a free online 9-week course based on this book with the author giving the online class. The latest offering of the course started Oct 4 and goes until Dec 16. If you're interested in that, I don't know if you could take it starting on your own now with access to the videos and course materials, or if you'd have to wait for the next offering. Here is a review by someone who took this course a couple years ago.

Disclaimer: I haven't read that book or taken this online class myself; it's just a potential idea that might be a fit or not

>So, I prefer perhaps a longer definition like "plant growth from light."

No, this is photosynthesis. Photomorphogenesis (photo morpho genesis) is how plants react and develop to light. Photosynthesis only has about 60 metabolic steps and I consider it easy to understand compared to photomorphogenesis. There is some interesting quantum mechanics involved with photosynthesis. FRET measurements are vital to my research in determining photosynthesis efficacy by spectra for different leaves. This is a good book to read if you go to that level.

>there is a lot unknown about this

Much, much more than you realize. A plant may have over 1000 light sensitive interacting proteins. There are at least 5 different phytochrome proteins. PHY-E works differently than the other 4. Arabidopsis thaliana, a model plant and "lab rat", has about 1400 light sensitive proteins. The function of the vast majority is still unknown.

>ratio of red to far-red goes into determining a plant's stockiness versus tall/thinness

Blue plays a bigger role through the phototropin proteins in every plant I've worked with.

>more blue light = more leaf expansion

Depends on the plant. You often end up with crinkled leaves since the leaf vein cells may not expand as much as other leaf cells. I got basil leaves to grow 4 times larger than normal using a minus blue light source (warm white 24 watt LED with a filter). I have generally found the opposite to be true- blue creates smaller leaves.

http://imgur.com/HzXKreR

Normally, sweet basil will not grow without some blue light. In this case I used blue light only on the stems. This is known as Selective Light Training.

In photomorphogenesis there's what's known as the "blue wall" and the "3 finger action response" (google them). 470nm greatly affects most blue sensitive proteins. 490nm does not- at least the phototropin proteins.

You're overlooking green/yellow/orange. Look at the front page of the lighting guide. This spectra also boosts auxin levels and important in the biosynthesis of ethylene, another plant hormone. There's a good reason that the spectra of HPS does so well in flowering.

>what is the "best" ratio of red | far-red | blue lighting? How are the different per plant type?

Hate to say this but it depends on the individual strain. Purple basil can react differently than lettuce leaf basil or sweet basil. Short answer- I don't know, there's hundreds of thousands of different strains of plants. I've seen testing at the local research university plant growth lab where white light beat color LEDs with sweet basil.

100 watt per square foot for CFLs for flowering. I always encourage people to use a light meter. I never give watts per plant, only watts per square foot. Veging takes about half the light as flowering.

>How much should the light be dispersed? Is there a chart or something that gives more detail on the amount of lighting and lighting dispersion?

Use your light meter. The reflector/lens/etc makes a big difference. In the lighting guide I talk about reflectors for CFLs.

>Are these good questions?

Quite good.

> What other questions should I ask with the goal of better understanding a practical grow light setup to optimize photomorphogenesis?

Try different combos of wavelengths.

>Do you have any recommendations for the setup of these experiments?

Stick with small plants and use 7 for the experiment and 7 for the control.

Micro Tom tomato

Lettuce including dwarf lettuce

Dwarf sugar peas

Keep in mind that a lux sensor/meter works great with white LEDs, would not trust them with color LEDs. The cheapest meter that can come somewhat close for good measurements with color LEDs is this $200 quantum light meter. It will not reliably work with 660nm LEDs. For that you need a $800 Licor meter. This Licor meter will not work with far red LEDs. For that you need a spectrometer. Mine cost about $2700 including fiber optic cable, two sensor heads and NIST traceable calibration.

You can always use any light sensor for relative measurements as long as the light source is the same. But keep in mind that with a true lux sensor, 620nm will give 3 times higher readings than 660nm although the radiant flux may be the same. Never get luminous and radiant flux confused.

You can also buy quantum light sensors in the $150 range. These "low" cost sensors will also not reliably read 660nm and far red LEDs. Multiple places sell them.

http://solarlight.com/product/par-quantum-light-sensor-pma-1132/

I have well over a hundred research papers/pdf files on plant lighting. I'm going to try to dig up a particularly good one. Forgot the name.

Good book:

http://www.amazon.com/Introduction-Radiometry-Photometry-Optoelectronics-library/dp/0890066787

Do you by chance have an Andriod smart phone or tablet? There's a lot of good apps that would be of use to you.

edit- a little bit here and there

That paper I wanted you to read- google "The Guiding Force of Photons"

Double slit experiment for the most basic explanation:

https://www.youtube.com/watch?v=DfPeprQ7oGc

And then, just get this book. Everything that I learned from the internet informally was covered in chapter 1 of this book:

Quantum Mechanics for Scientists and Engineers: