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Findings Could Lead to High-Yield Crops

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#1 DoctorG0nz0



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Posted 16 April 2012 - 05:05 PM

Thought this was interesting and wanted to share.

Brief Summary : A new understanding of how shade prodces auxins which may lead to an increase in yield from plants grown in agricultural conditions ( Packed in rows close together)


Excerpts from the article :

"We knew how leaves sensed light and that auxins drove growth, but we didn't understand the pathway that connected these two fundamental systems," says Joanne Chory, professor and director of the Salk's Plant Biology Laboratory and a Howard Hughes Medical Institute investigator. "Now that we know PIF7 is the relay, we have a new tool to develop crops that optimize field space and thus produce more food bud or feedstock for biofuels and biorenewable chemicals." (Fixed)

They showed that when a thale cress plant is placed in shade, a cascade of molecular changes occurs in the cells of the leaves: the PHYB photoreceptor causes chemical changes in PIF7, which then activates genes that direct the cell to produce auxin.

"We already knew that auxin is made in the leaves and travels to the stem to stimulate growth," says Chory. "Now we know how shade stimulates the leaves to produce auxin, and it turns out that it's a remarkably simple pathway to control such an important function."

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#2 ObserventOne



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Posted 17 April 2012 - 05:58 PM

Interesting... I could be completely wrong here but I seem to remember learning something in Biology about how Auxins stimulate plant cell elongation.

I think this would translate into the "stretch" we see when a plant is placed too far from its light source. I'm guessing the same thing occurs in nature when trees compete for light by stretching as tall and spindly as they can to escape the canopy of nearby trees.

In an agricultural context, wouldn't this increase a plant's susceptibility to lodging (falling over from being tall and weak)? Unless shading is being used in an intentional application to increase elongated growth in fiber and lumber producing plants like trees/ hemp and bamboo, I don't really see how it could improve the overall yield of fruit/ flower/ bud plants.

Am I way off?

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#3 Organic Gardener

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Posted 18 April 2012 - 07:26 AM

Auxins on Wiki

yeah I know it's wiki but it'll do.

On a cellular level

On the cellular level, auxin is essential for cell growth, affecting both cell division and cellular expansion. Auxin concentration level, together with other local factors, contributes to cell differentiation and specification of the cell fate.

Depending on the specific tissue, auxin may promote axial elongation (as in shoots), lateral expansion (as in root swelling), or isodiametric expansion (as in fruit growth). In some cases (coleoptile growth), auxin-promoted cellular expansion occurs in the absence of cell division. In other cases, auxin-promoted cell division and cell expansion may be closely sequenced within the same tissue (root initiation, fruit growth). In a living plant, auxins and other plant hormones nearly always appear to interact to determine patterns of plant development.

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#4 Haley



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Posted 21 April 2012 - 05:35 AM

Cell elongation = growth.
I think this would translate into the "stretch" we see when a plant is placed too far from its light source.
Same principle, different result.
If the light intensity is too low (or the spectrum is heavy on the red side), the result of auxin production is long internode spaces in an effort to get the apical meristem(s) closer to the light (higher intensity/energy).
As long as the intensity remains adequate, and there is adequate blue light to fuel chlorophyll synthesis, the internode spaces remain short and foliage production is lush.
This is why ordinary HPS bulbs produce lankier plants than MH or horticultural HPS bulbs employing a wider spectrum to provide more blue light.

And there's a genetic component as well, some strains have longer nodal spacing than others.

From the article
She added that the findings may offer new avenues for developing crops with stem architectures better suited to tightly planted field rows, making them less prone to shade avoidance syndrome. If successful, such crops would produce higher yields of foods and biofuels than existing strains.
Isn't that a SOG? I hope she's talking about selectively breeding these strains, not genetically engineering them.

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#5 Harvey_M


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Posted 21 April 2012 - 10:28 AM

I clicked on this thread because I, of course, am always looking to improve yield. However, I don't really see how any of that article is applicable to growing cannabis.

Trying to grow cannabis in a way that would trigger this "shade avoidance syndrome" just means you don't have enough light, and/or your plants are not spaced, pruned, cropped, etc correctly. With cannabis, regardless of genetics, you need to have good light hitting your trichomes, or you'll have a dramatically lower quality result.

However, if it were possible to genetically engineer a plant that produces only about 1/3 of the leaves you would normally expect during flowering, indoors, the yield could actually be improved, depending. Reason being that with any well tuned dwc or aero/nft, especially with co2, you have so many leaves within even 2 weeks of 12/12 that they block almost all of the light at the top layer, and they transpire all over each other to where you can shake water off of them, even with fans blowing. At that point, if you don't remove a significant quantity of leaves, you take a huge hit on yield and quality. I probably remove %80 of the leaves during a typical crop, and the increase in yield is about equivalent to adding co2, while the increase in quality is even more significant.

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