Lighting Hps or LED?

[lax123]

On a whim, I set three of the early flower plants half way between the hps and LED light spreads.. They always grow to the LED side. Always... It's worth noting.

Its the plants photomorphogenic response to the blue light in the spectrum. Cells in blue light expand less -but on the backside, where the blue light does not hit, the cells expand more in comparison, this translates into bending torward that light source. Doesnt necessarily mean it "likes" it more.

 

[F.N.]

photomorphogenic great word what does it mean?

 

[lax123]

actually in this case it´s called phototropism.
plants have light sensitive proteines/sensors

"Photomorphogenesis (light grown) involves the inhibition of stem elongation, the differentiation of chloroplasts and accumulation of chlorophyll, and the expansion of leaves. Thus the same stimulus causes opposite effects on cell elongation in leaves and stems. Photomorphogenesis can be induced by red, far red and blue light."
http://www.public.iastate.edu/~bot.512/lectures/Photo.htm

 

[Corgy]

To me it is all about efficiency; power consumption, running costs(new bulbs), longevity, heat generated(lack of), safety, ease of use and of course quality of harvested product.

The spectrum discussion is a bit moot in my opinion, just look at what reaper Magnamoto, cropper Tang and many others are achieving with Led's at a much lower cost that any other light source. Unless someone can show a controlled side-by-side grow, with say 50 plants in each light setup.....and that ain't gonna happen........and come up with a better total Watt/Time/gram and throw in quality for that matter, for another light source than LED.........

then for me, LED wins hands down.

lax123

actually in this case it´s called phototropism.
plants have light sensitive proteines/sensors

"Photomorphogenesis (light grown) involves the inhibition of stem elongation, the differentiation of chloroplasts and accumulation of chlorophyll, and the expansion of leaves. Thus the same stimulus causes opposite effects on cell elongation in leaves and stems. Photomorphogenesis can be induced by red, far red and blue light."
http://www.public.iastate.edu/~bot.5...ures/Photo.htm​

Since we are now also in the botanical realm too, (and I see the other thread has been locked for an Admin review due to some probing relevant GN questions, me thinks!!!), perhaps we can carry on here

---

Here´s another, slightly different diagram of the same process:

http://en.wikipedia.org/wiki/Phototropism

Phototropism

From Wikipedia, the free encyclopedia

Auxin distribution controls phototropism. 1. This is a normal plant that has the sun positioned almost directly over the plant. During this time, the auxin (pink dots) that lies within the plant is evenly distributed. 2. The sun is now positioned at an angle to the plant. The repositioning of the sun causes the auxin to move the other side of the plant, and becomes more concentrated. This overload of auxin next to these cells causes them to start to grow or elongate. 3. This results in the plant to look like it is growing toward the sun. 4.If the sun moves to the other side of the plant, the auxin would again move to the other side of the plant and become concentrated on the side of the plant that is farthest away from the sun. 5.The same growth or elongation of the cells on this side of plant would continue to grow towards the sun.​

The Thale Cress (Arabidopsis thaliana) is regulated by blue to UV light​

Phycomyces, a fungus, also exhibit phototropism​

Example on a Phalaenopsis​

Example on Azuki beans​

Phototropism is the growth of organisms in response to light. It is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light have a chemical called auxin that reacts when phototropism occurs. This causes the plant to have elongated cells on the farthest side from the light. Phototropism is one of the many plant tropisms or movements which respond to external stimuli. Growth towards a light source is called positive phototropism, while growth away from light is called negative phototropism. Most plant shoots exhibit positive phototropism, and rearrange their chloroplasts in the leaves to maximize photosynthetic energy and promote growth.[SUP][1][/SUP][SUP][2][/SUP] Roots usually exhibit negative phototropism, although gravitropism may play a larger role in root behavior and growth. Some vine shoot tips exhibit negative phototropism, which allows them to grow towards dark, solid objects and climb them. The combination of phototropism and gravitropism allow plants to grow in the correct direction.[SUP][3][/SUP]

Contents

[hide]​

• 1 Mechanism
  • 1.1 Five models of auxin distribution in phototropism
• 2 Effects of wavelength
• 3 See also
• 4 References
• 5 External links

Mechanism[edit]

There are several signaling molecules that help the plant determine where the light source is, and this activates several genes, which change the hormone gradients allowing the plant to grow towards the light. The very tip of the plant known as the coleoptile is necessary in light sensing.[SUP][1][/SUP] The middle portion of the coleoptile is the area where the shoot curvature occurs. The Cholodny-Went hypothesis, developed in the early 20th century, predicts that in the presence of asymmetric light, auxin will move towards the shaded side and promote elongation of the cells on that side to cause the plant to curve towards the light source.[SUP][4][/SUP] Auxins activate proton pumps, decreasing the pH in the cells on the dark side of the plant. This acidification of the cell wall region activates enzymes known as expansins which break bonds in the cell wall structure, making the cell walls less rigid. In addition, the acidic environment causes disruption of hydrogen bonds in the cellulose that makes up the cell wall. The decrease in cell wall strength causes cells to swell, exerting the mechanical pressure that drives phototropic movement.
A second group of genes, PIN genes, have been found to play a major role in phototropism. They are auxin transporters, so it is thought that they are responsible for the polarization of auxin. Specifically PIN3 has been identified as the primary auxin carrier.[SUP][5][/SUP] It is possible that phototropins receive light and inhibit the activity of PINOID kinase (PID), which then promotes the activity of PIN3. This activation of PIN3 leads to asymmetric distribution of auxin, which then leads to asymmetric elongation of cells in the stem.pin3 mutants had shorter hypocotyls and roots than the wild-type, and the same phenotype was seen in plants grown with auxin efflux inhibitors.[SUP][6][/SUP] Using anti-PIN3 immunogold labeling, movement of the PIN3 protein was observed. PIN3 is normally localized to the surface of hypocotyl and stem, but is also internalized in the presence of Brefeldin A (BFA), an exocytosis inhibitor. This mechanism allows PIN3 to be repositioned in response to an environmental stimulus. PIN3 and PIN7 proteins were thought to play a role in pulse-induced phototropism. The curvature responses in the "pin3" mutant were reduced significantly, but only slightly reduced in "pin7" mutants. There is some redundancy among "PIN1", "PIN3", and "PIN7", but it is thought that PIN3 plays a greater role in pulse-induced phototropism.[SUP][7][/SUP]
There are phototropins that are highly expressed in the upper region of coleoptiles. The two main phototropins are phot1 and phot2. phot2 single mutants have phototropic responses like that of the wild-type, but phot1 phot2 double mutants do not show any phototropic responses.[SUP][3][/SUP] The amounts of PHOT1 and PHOT2 present are different depending on the age of the plant and the intensity of the light. There is a high amount of PHOT2 present in mature Arabidopsis leaves and this was also seen in rice orthologs. The expression of PHOT1 and PHOT2 changes depending on the presence of blue or red light. There was a downregulation of PHOT1 mRNA in the presence of light, but upregulation of PHOT2 transcript. The levels of mRNA and protein present in the plant were dependent upon the age of the plant. This suggests that the phototropin expression levels change with the maturation of the leaves.[SUP][8][/SUP] Mature leaves contain chloroplasts that are essential in photosynthesis. Chloroplast rearrangement occurs in different light environments to maximize photosynthesis. There are several genes involved in plant phototropism including the NPH1 and NPL1 gene. They are both involved in chloroplast rearrangement.[SUP][2][/SUP] The nph1 and npl1 double mutants were found to have reduced phototropic responses. In fact, the two genes are both redundant in determining the curvature of the stem.
Five models of auxin distribution in phototropism[edit]

In 2012, Sakai and Haga[SUP][9][/SUP] outlined how different auxin concentrations could be arising on shaded and lighted side of the stem, giving birth to phototropic response. Five models in respect to stem phototropism have been proposed, using Arabidopsis as the study plant.

Five models showing how auxin is transported in the plant Arabidopsis.​

First modelIn the first model incoming light deactivates auxin on the light side of the plant allowing the shaded part to continue growing and eventually bend the plant over towards the light.[SUP][9][/SUP]
Second modelIn the second model light inhibits auxin biosynthesis on the light side of the plant, thus decreasing the concentration of auxin relative to the unaffected side.[SUP][9][/SUP]
Third modelIn the third model there is a horizontal flow of auxin from both the light and dark side of the plant. Incoming light causes more auxin to flow from the exposed side to the shaded side, increasing the concentration of auxin on the shaded side and thus more growth occurring.[SUP][9][/SUP]
Fourth modelIn the fourth model shows receiving light to inhibit auxin basipetal down to the exposed side, causing the auxin to only flow down the shaded side.[SUP][9][/SUP]
Fifth modelModel five encompasses elements of both model 3 and 4. The main auxin flow in this model comes from the top of the plant vertically down towards the base of the plant with some of the auxin travelling horizontally from the main auxin flow to both sides of the plant. Receiving light inhibits the horizontal auxin flow from the main vertical auxin flow to the irradiated exposed side. And according to the study by Sakai and Haga, the observed asymmetric auxin distribution and subsequent phototropic response in hypocotyls is seems most consistent with this fifth scenario.[SUP][9][/SUP]
Effects of wavelength[edit]

Phototropism in plants such as Arabidopsis thaliana is directed by blue light receptors called phototropins.[SUP][10][/SUP] Other photosensitive receptors in plants include phytochromes that sense red light[SUP][11][/SUP] and cryptochromes that sense blue light.[SUP][12][/SUP] Different organs of the plant may exhibit different phototropic reactions to different wavelengths of light. Stem tips exhibit positive phototropic reactions to blue light, while root tips exhibit negative phototropic reactions to blue light. Both root tips and most stem tips exhibit positive phototropism to red light. Cryptochromes are photoreceptors that absorb blue/ UV-A light, and they help control the circadian rhythm in plants and timing of flowering. Phytochromes are photoreceptors that sense red/far-red light, but they also absorb blue light. The combination of responses from phytochromes and cryptochromes allow the plant to respond to various kinds of light.[SUP][13][/SUP] Together phytochromes and cryptochromes inhibit gravitropism in hypocotyls and contribute to phototropism.[SUP][1][/SUP]
























http://en.wikipedia.org/wiki/Photomorphogenesis

Photomorphogenesis

From Wikipedia, the free encyclopedia


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[TD="class: mbox-text"]This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (October 2007)[/TD]
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In developmental biology, photomorphogenesis is light-mediated development. The photomorphogenesis of plants is often studied by using tightly frequency-controlled light sources to grow the plants.

Contents

[hide]​

• 1 Germination
  • 1.1 Comparison of dark-grown (etiolated) and light-grown (de-etiolated) seedlings
• 2 Photoreceptor systems in plants
• 3 Blue light systems
• 4 UV systems
• 5 References
• 6 External links

Germination[edit]

Light has profound effects on the development of plants. The most striking effects of light are observed when a germinating seedling emerges from the soil and is exposed to light for the first time.
Normally the seedling radicle (root) emerges first from the seed, and the shoot appears as the root becomes established. Later, with growth of the shoot (particularly when it emerges into the light) there is increased secondary root formation and branching. In this coordinated progression of developmental responses are early manifestations of correlative growth phenomena where the root affects the growth of the shoot and vice versa. To a large degree, the growth responses are hormone mediated.
In the absence of light, plants develop an etiolated growth pattern. Etiolation of the seedling causes it to become elongated, which may facilitate it emerging from the soil.
Comparison of dark-grown (etiolated) and light-grown (de-etiolated) seedlings[edit]

See also: Etiolation

A dicot seedling emerging from the ground displays an apical hook (in the hypocotyl in this case), a response to dark conditions​

Etiolated characteristics:

• Distinct apical hook (dicot) or coleoptile (monocot)

• No leaf growth

• No chlorophyll

• Rapid stem elongation

• Limited radial expansion of stem

• Limited root elongation

• Limited production of lateral roots

De-etiolated characteristics:

• Apical hook opens or coleoptile splits open

• Leaf growth promoted

• Chlorophyll produced

• Stem elongation suppressed

• Radial expansion of stem

• Root elongation promoted

• Lateral root development accelerated

The developmental changes characteristic of photomorphogenesis shown by de-etiolated seedlings, are induced by light. Typically, plants are responsive to wavelengths of light in the blue, red and far-red regions of the spectrum through the action of several different photosensory systems. The photoreceptors for red and far-red wavelengths are known as phytochromes. There are at least 5 members of the phytochrome family of photoreceptors. There are several blue light photoreceptors.
Photoreceptor systems in plants[edit]

Plants use phytochrome to detect and respond to red and far-red wavelengths.
Phytochromes are proteins with a light absorbing pigment attached (chromophore).
The chromophore is a linear tetrapyrrole called phytochromobilin.
The phytochrome apoprotein is synthesized in the Pr form. Upon binding the chromophore, the holoprotein becomes sensitive to light. If it absorbs red light it will change conformation to the biologically active Pfr form. The Pfr form can absorb far red light and switch back to the Pr form.
Most plants have multiple phytochromes encoded by different genes. The different forms of phytochrome control different responses but there is also a lot of redundancy so that in the absence of one phytochrome, another may take on the missing functions.
Arabidopsis has 5 phytochromes - PHYA, PHYB, PHYC, PHYD, PHYE
Molecular analyses of phytochrome and phytochrome-like genes in higher plants (ferns, mosses, algae) and photosynthetic bacteria have shown that phytochromes evolved from prokaryotic photoreceptors that predated the origin of plants.
Blue light systems[edit]

As for the red/far-red system, plants contain multiple blue light photoreceptors which have different functions.
Based on studies with action spectra, mutants and molecular analyses, it has been determined that higher plants contain at least 4, and probably 5, different blue light photoreceptors.
Cryptochromes were the first blue light receptors to be isolated and characterized from any organism. The proteins use a flavin as a chromophore. The cryptochromes have evolved from microbial DNA-photolyase, an enzyme that carries out light-dependent repair of UV damaged DNA.
Two cryptochromes have been identified in plants.
Cryptochromes control stem elongation, leaf expansion, circadian rhythms and flowering time.
In addition to blue light, cryptochromes also perceive long wavelength UV irradiation (UV-A).
Phototropin is the blue light photoreceptor that controls phototropism. It also uses flavin as chromophore. Only one phototropin has been identified so far (NPH1). Phototropin also perceives long wavelength UV irradiation (UV-A) in addition to blue light.
Recent experiments indicate that a 4th blue light receptor exists that uses a carotenoid as a chromophore. This new photoreceptor controls blue light induction of stomatal opening. However, the gene and protein have not yet been found.
Other blue light responses exist that seem to function in plants that are missing the cryptochrome, phototropin and carotenoid photoreceptors suggesting that at least one more will be found.
Since the cryptochromes were discovered in plants, several labs have identified homologous genes and photoreceptors in a number of other organisms, including humans, mice and flies. It appears that in mammals and flies, the cryptochromes function in entrainment of the biological clock. Indeed, in flies, a cryptochrome may be a functional part of the clock mechanism.
UV systems[edit]

Plants show various responses to UV light. UVR8 has been shown to be a UV-B receptor.

 

[Hapa]

Aloha DrOtto~
This is something I'm looking into right this minute too!
but... ok ok...
I'mma need to spark up this doobie so I can get down on this reading.

I'm looking for a reasonably priced solution to my heat issues in summer so...

 

[xotorazeko]

Here is what I know:

1. CFLs scatter the light all over the place. A lot of this light gets lost UNLESS you use a good reflector right on top to redirect rays back down towards the plants.

2. LEDs are good. They are very efficient and can be even more efficient if you know how to use them. Oh, and they are dirt cheap.

With LEDs:

You can virtually have no heat issue. That means, you can keep the lights as close as you want.

Lumen ratings are extracted (inverse square law) with each feet you get away from light source. So 3 feet down, 16k lumens becomes 2k per square feet.

You don't need to change the bulbs either.

Well everyone I am confused on what route to choose for my upgrade. I'm a small scale grower. I have the room for about 4 to 5 good size plants 3.5x3.5x9 grow space and currently use cfl's. A lot of them too. I'm at around 4000lumens per square ft. I am saving for an upgrade and I'm stuck choosing between hps and LED.
Im well educated when it comes to hps lighting. But I don't know to much about LED!?!?!
How much LED lights would I need for my space? What is the cost comparison between the two? Will LED last longer than HPs? I just don't know what to do!? As much info as possible would help me the most. I'll continue to pick through this site to find more info. But if anyone has experience with the two styles of light and could fil me in it would be great. Again, what kind of LED Would I need? How many? How much? Ect. Thanks guys

 

[MisterHarpy]

I may get crucified for this but in Europe there's huge greenhouses that run 20,000-40,000 1000w hps' made by a company in Holland called gavita. If there was any better light source i would imagine they would be running something other than those.

If the leds were as powerful and really saved that much money , these huge ops running mega watts of lights would easily run leds.

Colorado and Washington have huge legal and medical warehouses that run the same lights as the big greenhouses in Europe.

I personally upgraded to these type of lights from a standard 1000w air cooled.

I figure why not get the best equipment when i want to produce the best medicine.

i have the 600s and they are individually brighter than my old 1kw. When they are both running i need sunglasses in my 5x8 room.

Seriously these lights are the shiznit.
Best thing about them is you dont have to worry about matching bulb to ballast anymore.

Cfls waste a lot of power. (2) 55w & (2)26w cfls use as many amps as one of the 600w gavitas on half power.

Think about it that way maybe. How many watts of cfls are u using? Then check the bulbfor amp rating and you will be surprised how inefficient cfls are.

http://www.dailymail.co.uk/sciencet...ortages-boosting-plant-growth-LED-lights.html its not that companies won't use led because its superior but when you scale that big,imagine the cost of 100 bulbs vs 100 panels then it makes a huge difference specially with companies who used one method there whole life. They look at numbers and with a huge grow yes the HP's will have better coverage but as you can see in the article coverage isn't everything

 

[growbiewon]

Those large green houses will use twenty thousand 1kw lamps. Every year hundreds of thousands of complete fixtures are sold by gavita to these places. Believe me with a few megawatts of juice per month if the benefits of leds were so apparent there would be no issuse spending the same price for a gavita 1000 complete fixture and switching to a mars ll of same price. They would be all over the power savings. mega watt equals one million watts.

These arent even pot plants....lol thats a lot of power for roses..not my garden...lol duh?

Now here's a proper cannabis grow using gavitas, found pic online, not my herb.

 

[oldster]

Cfls waste a lot of power. (2) 55w & (2)26w cfls use as many amps as one of the 600w gavitas on half power.

Think about it that way maybe. How many watts of cfls are u using? Then check the bulbfor amp rating and you will be surprised how inefficient cfls are..

Just to keep things accurate, watts are simply a measure of volts * amps. With CFLs you need to make sure that you are looking at actual watts not equivalent watts which is how they compare to a incandescent bulb. If a bulbs amp rating indicates something else then something about its labeling is not correct unless they are showing the initial startup amps which will always be higher than running amps for both light types

2 55 watt CFLs and 2 26 watt cfls that are correctly labeled will use 162 watts. A 600 watt HPS will at 50% is going to use 300 about watts. It is true that HPS will produce more lumans per watt than CFL.

Many commercial greenhouses are either producing bedding plants or produce during cold/cool weather. The low heat aspect of LEDs does not save them money in that situation since they have to use more energy to produce heat to keep things warm enough.

 

[growbiewon]

Im talking actual watts. Cfls are internally ballasted. A real watt 55w actually draws more power than 55w described as amp draw. On the 55w light its lable states it uses .8a which equates to 96w @120 v . So in reality you're paying for 96w to the power co but only giving the plants 55W. IM not stating compared to watts but actual cfl watts.

My gavita is very efficient. It only takes 630w to produce 600W.

Try out a kill a watt meter they are pretty cool.