How light spectrum affects nutrient use in plant tissue...

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SpiderK

SpiderK

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As the transpiration process breaks down it can flash nutrient deficiency but it's not, so it's not a result of the soil but the plant uptake issues that play out together because of the heat, humidity, root oxygen ect play a part but some times it not a fix in the soil but in the environment itself. that started the cascade and is the root of the real problem ....

and a nute fix might help short term but the issue snowball and peeps do not know whats going on at that point adjusting this or that off visuals .... as it breaks down further, new issues pop up ....

can it be something else, yep but it is one of the things that happen indoor.
 
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tromak

tromak

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It's pretty simple, cannabis grows different under different light spectrums. Even when not in flowering. Of course the nutrient uptake is different. You should rotate the lights or the plant and see if that changes anything.
 
FlyinJStable

FlyinJStable

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I have been hangin out about a year on the Forum but more than that I have had my eye on advanced lighting no not so much om plants but cars, You may say well what the F does this have to do with lights on our beloved babies well Little but the same Large Industry that build and invent or manufacture automotive lighting for the big 3 or the overseas Market has one hell of a lot more RnD than some of the Ag researchers.
This is Sad but true well here is just some great info Good for Larger scale growers who follow the LED stuff too.
A Company Called Nikkiso has a very user friendly Invention for purification of water.

Nikkiso has developed a module that can be fitted to food machinery to sterilize water on the move.

TOKYO -- It took a decade of work and the help of two Nobel laureates, but industrial pump manufacturer Nikkiso is finally gearing up for the mass production of deep ultraviolet light-emitting diodes.

1


This module uses the light from deep UV LEDs to disinfect running water.

These deep UV LEDs emit even shorter wavelengths of light than blue LEDs, and they have promising applications. Nikkiso envisions applications for its deep UV LEDs in three broad fields.
First is the environmental field, where the sterilizing effects of deep UV radiation can be put to use disinfecting water and sewage. This is already done using mercury lamps, but the new LEDs have many advantages: They are smaller and can run on lower voltage, around 5-7 volts. They are far more durable, lasting more than 10,000 hours, compared to around 3,000 to 5,000 hours for mercury lamps. Finally, they do not use toxic mercury.
The second field is medicine, where Nikkiso anticipates a wide range of applications in addition to the sterilization of medical instrumentation.
One example is dermatology, where selective dosing with different wavelengths of deep UV radiation can be used as a form of light therapy to treat skin disorders.
Another example is the measurement of the purity and density of proteins and DNA by combining the LEDs with photodetectors.
And Nikkiso has already incorporated the LEDs into its kidney dialysis machines as a way to check for the elimination of waste materials from the blood.
Industrial applications are the third promising field. Used with UV-hardening resins for bonding and coating processes, the LEDs can improve the efficiency of the production line because they can reach stable output much faster than mercury lamps, which take more time to warm up.
But even as the company works to propose applications in these fields, it also intends to utilize the deep UV LEDs in its own products.
Together with its pump technologies, Nikkiso has developed a module that can be fitted to food machinery to sterilize water on the move.
The hard road
It was clear from the start -- Nikkiso first began developing deep UV LEDs in 2006 -- that it would be difficult to grow crystals of uniform properties in order to mass-produce high-quality versions of the elements

For help and guidance, the company turned to Isamu Akasaki of Meijo University and Hiroshi Amano of Nagoya University, both of whom shared the 2014 Nobel Prize in physics for their work on blue LEDs with Shuji Nakamura of University of California, Santa Barbara.
"We doggedly pursued the research, just like these pioneers," recalled Shigeo Maruo, who heads the company's R&D subsidiary Nikkiso Giken.
With the guidance of the two future Nobel laureates, Maruo and the staff at Nikkiso Giken fine-tuned their mass-production technologies and began selling samples of their deep UV LEDs in 2012.
Nikkiso completed a 2.2 billion yen ($18.5 million) production facility in Ishikawa Prefecture this past June that is now in trial operation. Full-scale mass production of the LEDs is expected to start in April.
"We're confident of the performance of these LEDs," Maruo said, "and the next step now is to ascertain customer needs."
With rivals like Asahi Kasei also developing deep UV LEDs, this nascent market is likely to see intense competition in the years ahead.
For Nikkiso, that means continuing to boost performance and explore new fields for its deep UV LEDs.
"To lead a market," Maruo said, "you always need to be thinking about the next move."

The reason I put this here is because IMHO looking outside the normal sources for help in a growing industry like MMJ or fledgling recreational markets in the Large scale will must Rely on Clean Clean Clean growing environmental standards..
ISO DANK . . . .
isnt that what were after . . .
just my thoughts I hope it was cool to share Cap.
FlyJ
 
MGRox

MGRox

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I'm a bit late to this original question; but got compelled to do some sniffing around. I hope this ends up being on point and informative. I do not want to butt in or state things that are commonly known. Hopefully as well this doesn't get too long. I've been down several "rabbit holes" recently and like this; they can seem to keep expanding as you go down, but some are connecting now.

This is presented as data and possible rationalizations or theorizations for things related to light and nutrient use.

Okay, so this cannot be covered without bringing you all in to the rabbit hole some; though many of you I'm sure will know some, much or possibly all. Hopefully I can put this together so things make sense for those that may not know all these aspects (I did not).
First we need to look at "light-dependent reactions" (wiki) and "light-independent reactions" (wiki).
-Of particular note here is Photosystem I and Photosystem II (PSI / PSII) along with Cytochrome for dependent reactions and Calvin cycle for independent.
There is a good You Tube video that explains really well how PSI and PSII were discovered and also explains their interconnection fairly well. (Video)
Finally here with, sort of, the primer section. Another good paper (.doc) that explains PSI and PSII and their differences (Paper)
-From these last 2 links (video / paper) there are a few things to take note of. With the video, the Emerson Enhancement Effect (EEE) and points of "heat" noted. With the paper, the non-linear (cyclic) electron flow and its' involvement with ferrodoxin. (This also is an area where the Cytochrome is useful from wiki links.) As well, that these PSI / PSII reactions occur in the thylakoid membrane. The last thing to note with the paper is PSII Light Harvesting complex (LHC).

that's the end of the "primer" section:
Now looking at ion uptake in regards to spectrum (as per the OP title); I did find one good paper (though they didn't cover all elements). (Paper)

"...the most complete action spectrum for inorganic ion uptake by green plant is that of van Lookeren Campagne (1957). He found that net Cl influx in Vallisneria spiralis was light-stimulated with an action spectrum identical to that of photosynthesis in this organism." Simonis and Mechler (1963) showed that the incorporation of exogenous Pi into TCA-solubule compounds had and action spectrum similar to that of photosynthesis and of total Pi uptake, in Ankistrodesmus braunii."
....."These data would strongly suggest that these active anion influx processes are light-stimulated via the photosynthetic pigments. No data seems to be available in the literature for teh action spectrum of cation transport processes"


The paper goes on to look at CO2 fixation in relation to specific spectrums and intensities.
"Fig 1. showes the effect of intensity of light of 448 nm on CO2 fixation in Hydrodictyon africanum. It will be seen that there is a wide range of light intensities at which the rate of photosynthesis is proportional to light intensity, and that there is a fairly abrupt transition to the light-saturated rate."
......
"Similar linear relations between light intensity and rate of photosynthesis have been found in experiment with light of 680 nm and 539 nm. The light-saturated rate of photosynthesis is the same for 680 nm light as for the 448 nm light, anf for flourescent ('white') light. The highest intensity available with the 539 nm light (14,800 erg /cm2 /sec) was insufficient to saturate photosynthesis. "

Figure 1
CO2 fixation vs light intenstiy 448 fig 1
Of note here is that (with CO2 fixation) the saturation was the same for 448, 680 and white light, but that 539 was able to saturate higher. Saturation point shown @ 10,000 erg/cm2/sec . This equals 10 Watts/m2 of that individual spectrum (range).

"Fig. 2 shows the pooled results of a number of experiments in which the effect on photosynthesis of an incident intensity of 500 erg/cm2/sec of light of various wavelenghts was determined...........It will be seen that the resulting action spectrum is typical of absorption by chlorophyll, with a peak in the blue and another in the red at about 675 nm."
Figure 2
CO2 fixation vs spectrum fig 2

The paper goes on then, to cover influx saturation intensities and influx over various wavelengths for K, Cl and Na (including some also on efflux).
Regarding K influx;
"It will be seen that light saturation occurs at about 2,000 erg/cm2/sec of 448 nm light, and that the influx is linearly related to light intensity below 1,000 erg/cm2/sec. Similar results have been obtained at other wavelengths: light-saturated rates of K influx are identical at 448, 539, 680 and 710 nm, and in fluorescent light.
......"Fig 4 shows the action spectrum for K influx, expressed in the same way as Fig 2 for photosynthesis. The red and blue peaks, and the green trough in the action spectrum are quantitatively similar to those in the photosynthetic action spectrum"


Regarding Cl influx;
"Fig 5 shows the intensity dependence of Cl influx supported by 448 nm light. It will be seen that the process saturates at about 1,000 erg/cm2/sec of 448 nm light, and that below this intensity the Cl influx is linearly dependent on light intensity. ...... Light saturated rates of Cl influx are identical at 448, 539 and 680 nm and under fluorescent illumination."
......"Fig 6 shows the action spectrum for Cl influx, expressed in the same way as the results in Figs. 2 and 4. The red and blue peaks, the green trough and the rapid decline on the long wavelength side of red peak, are all quantitatively similar to these features of the photosynthetic action spectrum shown in Fig 2. "

The above paper was also attempting to make correlations with these ions (influx/efflux) and their dependency on PSI and PSII systems; however the tests they ran are very specific to the question asked in the op. From what was shown or referenced (P, K, Cl); all the elements had influx saturation equal regardless of wavelength. As well, in all cases the influx percentages (over wavelengths) matched photosynthetic actions spectrum. Smaller but noteworthy is that saturation intensities for each of these ions (related to influx) was much lower than the total CO2 saturation intensity (@448,680) wavelengths.

Though not all elements have been done in this way; one could conjecture that other ions would follow similar suit if they are easily translocated / moved / uptaken. I.E. it does not appear that spectrum "in itself" can "alter" (per se) certain ions over others; nor that spectrum may even play a role directly. The evidence presented there would tend to lead to the assumption that the typical chlorophyll action spectrum would also compare with relative influx amounts of these ions too.
Thinking about this, I suppose it does seem rather logical as action spectrum is already so limited in terms of high productivity bands and that further limiting certain ions in specific nm ranges would also require more intricacy of internal design.

So, now we are still left with obvious variations seen with MH / HPS bulbs and that in certain circumstances (HPS / LED) Mg and Ca may be needed in higher quantities along with "possibly" P. How the heck can we resolve these issues then, right? If in fact spectrum isn't playing the role, what is?

Well if you've read up until now, at least the variation in MH/HPS can reach some level of theorization. If we consider that HPS has a higher level of both 680 and 700 nm than MH; then part of this difference could very well be related to "emerson enhancement effect" (EEE) above. The HPS could "Drive" PSI specifically along with PSII more effectively than an MH bulb. As a result of this there should be proportionally higher ATP and NADP synthesis in HPS lamps. As well the higher overall PPD of HPS in these spectra will also be likely to introduce "cyclic flow" via PSI while waiting on further NADP (calvin cycle not related to light). Both of these components would serve to possibly increase the demand for P vs MH bulbs. Most decidedly at least HPS will have a greater effect with PSI / PSII and likely EEE.

In order to look at increasing requirements of Ca and Mg; we must look into the realm of "photoinhibition" (wiki)
Yup. a response from too much light (though again consider saturations and wavelengths from the paper above). Now this is not necessarily what you might think, e.g. bleaching or burning etc. It seems that some level of photoinhibition is quite common and plants have several means of adapting to various levels of "excess" intensities.
Note from the wiki that "Photosystem II is damaged by light irrespective of light intensity."

Also at this point there is another component that needs to be known / considered too; That is the "Xanthophyll Cycle" (Wiki)
Xanthophylls are accessory or antennae pigments (along with carontenes), that most notably are utilized in the "non-photochemical quenching" (NPQ). (Wiki)
Here is another paper. (Paper) It does a good job at showing visualizations of energy transfer from xanthophylls, action spectrum of these antennae along with a good final representation of the "Z scheme"
(with that paper also notice the structure of chlorophyll a/b and that the both contain Mg in their centers.)

There are several stages of plant responses to excess photons (including total or specific wavelengths) that become increasing larger or more dramatic, with respect to the amount of excess.
Here is a simple image that does well at showing various steps;
Photoinhibition pathway
Also a quick quote from the paper (doesn't need linked really)
"Plants can try to protect the photosystems from too much light and avoid photoinhibition, by dissipating energy in form of heat. If heat dissipation can’t cope with protecting the photosynthetic apparatus and, toxic species, like superoxide (O2-), singlet oxygen (1O2*) and hydrogen peroxide(H2O2), start to be produced through the joint of excited chlorophyll and molecules of oxygen, other protective mechanisms are needed. Carotenoids suppress the excited state of chlorophyll and releases energy as heat. Xanthophylls (violaxanthin, antheraxanthin and zeaxanthin), which are, as well, carotenoids, have a protective role when the photosynthetic apparatus is exposed to too much light. This cycle converts violaxanthin into zeaxanthin under high light, and large amounts of zeaxanthin retards the damage of the D1 protein (Alves et. al , 2002)."

The first and weakest method of dealing with excess photon influx is via Heat production (video at the top also pointed to heat generation points). This is also where we begin to see Ca come in to play.
(Paper)
"TRANSTHYLAKOID ApH. The most rapid response to excess light is the increase in the rate constant for thermal energy dissipation from the PSII antenna and/or reaction center (kheat) associated with the development of the transthylakoid ApH gradient (141). The mechanismof this affect of increasing ApH is uncertain, but may involve aggregation of LHCI~ particles, facilitating increased kheat in the antenna (61) Alternatively, or in addition, the pH change may cause a reversible inactivation of the PSII reaction center involving loss of Ca and increasing kheat at the reaction center (142)."

The next process triggered to avert production of "reactive oxygen species" (ROS) from excess photons, comes about from the Xanthophyll Cycle.
"A more profound change in PSII can be inferred from changes in fluorescence yields and q~ associated with the epoxidation state of xanthophyll cycle intermediates in both higher plants (28, 29) and algae(100, 101). The xanthophyll cycle in higher plants and green algae consists of conversion of the diepoxide violaxanthin to the epoxide-free zeaxanthin, via the monoepoxide antheroxanthin, when light absorption exceeds photochemical utilization. Epoxidation back to violaxanthin through antheroxanthin occurs in darkness or when light absorption is no longer in excess."

Also from this paper we can relate when damage does occur to PSII systems; where it is likely to occur or what area it will act upon.
"Early research into mechanisms of photoinhibition noted an associated loss of the D1 32kDa-PSII reaction center polypeptide............ Subsequent studies associated damage and loss of D1 with slowly reversible photoinhibition, and there is now consensus that when photoinhibition involves damage, D1 is the first site to be affected (105). Among the chloroplast-encoded polypeptides, D1 shows the most rapid turnover, even in low light (73), with an estimated tl/2 of approximately 2h (134). Photoinhibitory loss of D1 should only inhibit photosynthesis if the rate of repair fails to keep pace with the rate of damage."
.......
"The extent of photoinhibition will not only depend on the rate of D1 damage, but also on the rates of migration of the damaged and repaired PSII within the membrane, degradation of the damage D1, and synthesis of new D1. All these factors can contribute to the extent and rate of recovery from photoinhibition and may explain part of the interaction between photoinhibition and other environmental variables, particularly with respect to recovery where replacement of D1 is necessary to restore the pool of PSII."
......
"It therefore seems likely that the xanthophyll cycle is a, or the, major initial mechanism of decrease in PSII efficiency in sun leaves, and a first line of defense against PSII over-excitation during absorption of light in excess of photochemical utilization (29). Evidence of increased capacity for both D1 synthesis and xanthophyll cycle activity during acclimation to high light, indicates that both are probably critical to surviving excess light.
Shade plants appear to have a much lower capacity for xanthophyll cycle-related thermal energy dissipation (29) and for D1 repair (102, 138). observation is paralleled by the situation at low temperatures, where enzyme activities within both the xanthophyll and Dl-repair cycles will be limited (55, 106).

With the above we can see that heat production (resulting in Ca loss) and the xanthophyll cycle, though initial, are not able (nor designed) to eliminate destruction and repair of the D1. Also, that the overall negative photoihibitory effect (since D1 cycling is always occurring) is related to a plants' ability to both restore D1 and to prevent it's initial degradation. I read so much and I'm not sure if one of these links will contain it; however it should be noted that, plants are always trying to achieve a 1:1 equilibrium with destruction and repair of this D1 in PSII.

So then what are contributors to help reduce this destruction and repair?
This brings us to another paper. (Paper)
"Overcoming photodamage to PSII for photosynthetic organisms is the rapid and efficient repair of the damage, which requires the synthesis of these proteins de novo. Thus, identifying mechanisms to accelerate the repair rate of thylakoid proteins under excess light conditions is of great importance."
........
"It has been reported that Ca2+ improvement of photosynthesis is related to enhancing the activity of antioxidant enzymes to alleviate reactive oxygen species (ROS) accumulation ( Zhao and Tan 2005; Tan et al.2011). The decrease in intracellular ROS contributes to the protection of PSII proteins to alleviate the photodamage under light and salt stress ( Al‐Taweel et al. 2007) because high ROS levels could suppress the synthesis of the D1 protein and almost other proteins (Nishiyama et al. 2001, 2004; Allakhverdiev and Murata 2004). Thus, the protein‐synthetic machinery may be a specific target of inactivation by ROS during photoinhibition. It can be speculated that exogenous Ca2+ may play a role in protecting the subunits of PSII reaction centers from photoinhibition by reducing the generation of ROS. Additionally, it has been reported that the Ca2+ could stimulate the rate of electron transports on the acceptor side in PSII (Seminet al.1998);"
......
Ca+ treatments contribute to the increase of the xanthophyll cycle‐dependent energy dissipation (NPQ) (Figure 2) and attenuate PSII photoinhibition (Yang et al. 2013). The decrease in qP was accompanied by marked increases in NPQ, and the increases in NPQ may accelerate the repair of PSII without significant effects on photodamage to PSII (Sarvikaset al. 2006; Takahashi et al. 2009).
....
The efficient ROS scavenging could reduce the damage to membrane lipids, enhance the repair of PSII, and sustain the photosynthetic properties. The increase of antioxidant enzyme activity can be considered as an essential mechanism in the cellular defense strategy against oxidative stress (Shi et al. 2006). In the present study, Ca2+ treatments could have helped to scavenge ROS by inducing the increase of activity of some antioxidant enzymes, for example, APX, SOD, and CAT (Table 1). The lower ROS accumulation resulted in slight damage to cell membranes of Ca2+ ‐treated seedlings (Figure 3) reflected by MDA and ion leakage, which are commonly considered as indexes of membrane damage or deterioration (Kwon et al. 2002; Yabuta et al. 2002). Therefore, exogenous Ca2+ seems to play an important role in alleviation of oxidative stress and damages to cellular components such as membrane lipids.
...
Under heat and HI stress, the more PSII dimers and monomers in the Ca2+ ‐treated seedlings suggested that Ca2+ may provide stability to these protein complexes. That is to say, Ca2+ may play an important role in the maintenance of PSII activity under heat and HI stress (Figure 4).
...
When ROS were eliminated by AsA, the lower portion was concluded to be caused by Ca2+ deficiency, and it could be indicated that Ca was involved in the protein repair process of PSII photo-inhibition.
....
As a second messenger in plants, Ca2+ plays a pivotal role in thesignal transduction pathway under abiotic stress.


Further information about Ca and PSII photoinhibition is included here: (Paper)
(pg. 405)
"In the thylakoid, calcium ions are necessary for the function and structural assembly of the oxygen-evolving complex (OEC) of phototsystem II (PSII). The PSII OEC is a multimeric complex in the thylakoid lumen responsible for light-dependent oxygen evolution in plants. Functional assembly of PSII and OEC requires that all essential polypeptides and cofactors are present in the stroma, thylakoid membrane or thylakoid lumen. "
"Therefore, both the initial assembly of PSII and its subsequent reassembly after photoinhibition require calcium availability in the thylakoid lumen. Furthermore, Ca++ in the thlyakoid lumen has been implicated in the stabilization of the high redox potential form of cytocrhrome b-599 (McNamera and Gounaris, 1995). All of these processes require the availability of Ca++ in the thylakoid lumen.

As can be seen from the previous section along with the above, that calcium is involved at many levels of photoinhibition with PSII. This includes the heat stage, xanthophyll cycle, ROS NPQ; as well as its' role in reducing D1 decay along with expediting recovery. It would seem reasonable to surmise that seemingly higher calcium requirements of plants, upon exposure of certain light sources (HPS LED) above saturation levels; could very well be related to the "level" of destructive photoinhibition being higher with these sources versus daylight. E.G. at the very least from higher levels of NPQ in the xanthophyll cycle, but more probably and increase in the D1 "cycling" of PSII resulting in increasing Cystolic Calcium demand.

Now we have theorized about P (some) and Ca, but this still leaves the evidence (specifically with LED's) of increased Mg demand. To discern where and how increased Mg might come into play, we have to look now at Photosystem I (PSI).

A good starting point is here (Paper)
"Considering the factors to induce the inhibition of PSI, i.e., light, oxygen, and the input of electrons from PSII, it is natural to assume that the reactive oxygen species brought about by the reduction of oxygen is the direct cause of inhibition. One-electron reduction of oxygen produces the superoxide anion radical, which could dismutate and be converted into hydrogen peroxide. In the presence of reduced metal ions, hydrogen peroxide is converted to hydroxyl radical, which is highly reactive and destroys biological components within the diffusion limit (Asada, 1999).
......
"The addition of hydrogen peroxide during illumination of thylakoid membranes, however, caused the complete loss of the photooxidation of P700 (Sonoike et al., 1997). These results suggest that the photoreduction of the iron-sulfur centers on acceptor side of PSI by light illumination is the key to the problem. Hydroxyl radical, a most reactive species of active oxygen, is usually generated by a reaction between hydrogen peroxide and a reduced metal ion in a process called the Fenton reaction. It is plausible to assume that the hydroxyl radical, which is generated by the reaction between hydrogen peroxide and photoreduced iron-sulfur senters, destroys PSI at the site of production of hydroxyl radicals. "

--A note here to help, remember the beginning papers talking about PSI cycling and its' containing compound Ferrodoxin (an Iron- sulfate compond).

"P700, the reaction center chlorophyll of PSI, could be destroyed under high photon flux densities (Terashima et al., 1994)."
...
"Light-dependent fragmentation was also reported in wheat chloroplasts for the large subunit of Rubisco (Ishida et al., 1997,1998). .......... The degradation of Rubisco is also observed in the exposure of the protein to a hydroxl radical generating system (Ishida et al.,1999), and the site of cleavage was around the active site of they enzyme (Luo et al., 2002). These results indicate that Rubisco is inactivated by hydroxyl radical produced by the Fenton reaction between hydrogen peroxide and a reduced metal ion, both produced by photosynthetic electron transfer through PSI."
......
"Furthermore, fragmentation of Rubisco was also reported upon the light / chilling treatment of cucumber leaves in vivo, a condition in which PSI is photoinhibited (Nakano et al., 2006). .........Rubisco itself does not contain iron, but several divalent cations including iron could bind they enzyme to activate it in place of magnesium (Christeller 1981) forming a metal-substrate complex at the active site of the enzyme (Branden et al. 1984). Since the site of cleavage of Rubisco in vivo was also very specific and might be near the active site of the enzyme (Nakano et al. 2006), it is tempting to assume that the iron, which is released from iron-sulfur centers of PSI to stroma upon photoinhibtion of PSI, binds to Rubisco in the place of magnesium and triggers the degradation of the enzyme"

From this we can see that damage to the PSI photosystem via destructive photoinhibition, likely leads to a significant decomposition of Rubisco. As well, that iron can take the place of Mg where otherwise needed (though leads to destruction too). So then we need to consider what role Mg may play with Rubisco.
It may help here to again refer to the "calvin cycle" (Wikibooks)
"- Rubisco: For activity, it requires a bound divalent metal ion, commonly magnesium ion. By stabilizing a negative charge, the magnesium ion serves to activate a bound substrate molecule. It requires a carbon dioxide molecule other than the substrate to conclude the assembly of the magnesium ion binding site in rubisco. This carbon dioxide molecule is added to the uncharged ε-amino group of lysine 201 which forms a carbamate. Then, the negatively charged adduct binds to the magnesium ion. Although the formation of the carbamate will form spontaneously at a lower rate, it is enabled by the enzyme rubisco activase. Magnesium ion plays an important role in binding ribulose 1,5-bisphosphate and activating it to react with carbon dioxide. Magnesium ion and ribulose 1,5-bisphosphate bind together through its keto and adjacent hydroxyl group. The complex forms an enediolate intermediate through deprotonation. This reactive species couples with carbon dioxide and forms a new carbon-carbon bond. Including the newly formed carboxylate, the product is coordinated to the magnesium ion through three groups."
Activation of calvin cycle
"Regulation occurs when the stromal environment alters by the light reactions. pH increases in the light reactions and concentrations of magnesium ion, NADPH, and reduced ferredoxin. These changes help couple the Calvin cycle to the light reactions. Specifically, rubisco gets activated when the concentration of these molecules increases and the pH increases. Activity of rubisco increases because light creates the carbamate formation which is a necessity in enzyme activities. In the stroma, when the concentration of magnesium ion increases, the pH also increases from 7 to 8. From the thylakoid space, the magnesium ions are released in order to create the influx of protons into the stroma. Carbon dioxide is added to the rubisco’s deprotonated form of lysine 201 while magnesium ion is bound to the carbamate in order to generate enzyme’s active form. Therefore, the light generates the regulatory signals, ATP, and NADPH."


Another paper talks further about Rubisco (Paper)
"To be functional, Rubisco requires prior activation by carbamylation of the ε-amino group of active-site Lys201 (Lorimer and Miziorko, 1980) by a CO2 molecule, which is distinct from the substrate-CO2. The carbamylated Lys201 is stabilized by the binding of magnesium ion to the carbamate."

"One of the key players in the reaction catalysed by Rubisco is the magnesium ion. Apart from the carbamylated Lys201 which provides a monodentate ligand, the magnesium ion is liganded by two (monodentate) carboxylate ligands provided by Asp203 and Glu204 (Fig. 3) and three water molecules (Andersson et al., 1989). RuBP replaces two of these water molecules. For the reaction to proceed, a tight control of the charge distribution around the metal ion is crucial (Taylor and Andersson, 1997a) and this presumably also includes residues outside the immediate co-ordination sphere."
......
"CO2 replaces the last Mg2+-co-ordinated water molecule and adds to the enediol directly without forming a Michaelis complex (Pierce et al., 1986; Mauser et al., 2001). The resulting six-carbon compound, 3-keto-2′-carboxyarabinitol-1,5-bisphosphate is relatively stable and can be isolated (Lorimer et al., 1986)."


Other information (not all specifically related) about Mg can be found also and is of some note for awareness. (wiki)

"For example, ATP (adenosine triphosphate), the main source of energy in cells, must be bound to a magnesium ion in order to be biologically active. What is called ATP is often actually Mg-ATP.[4] As such, magnesium plays a role in the stability of all polyphosphate compounds in the cells, including those associated with the synthesis of DNA and RNA."
........
"Within individual plant cells, the Mg2+ requirements are largely the same as for all cellular life; Mg2+ is used to stabilise membranes, is vital to the utilisation of ATP, is extensively involved in the nucleic acid biochemistry, and is a cofactor for many enzymes (including the ribosome). Also, Mg2+ is the coordinating ion in the chlorophyll molecule."
........
"Thylakoid stacking is stabilised by Mg2+ and is important for the efficiency of photosynthesis, allowing phase transitions to occur.[69]"

It can be seen then, that Mg plays a critical role with Rubisco activation / catalysis; along with the requirement of Mg thylakoid levels as well as stabilizing intermediary products. From this we could theorize that destructive photoinhibition of PSI, leading to a destruction of Rubisco; would increase Mg utilization and probably necessitate higher concentration levels in these localized membranes. With the last set of quotes, it is also seen that Mg is required for ATP to become active. Further (though not specifically covered) "thylakoid stacking" is one possible response of plants to reduce photoinhibtion and, as well, is shown to require Mg for stabilization.

---------------

In conclusion, it would seem very practical and probable that;

- Efficient activation and optimization of both PSI and PSII systems can optimize photosynthetic processes (at levels lower than destructive photoinhibition) and thus indirectly increase P utilization; required for ATP and NADP along with ATP cycling. This effect would be most notable with PPD's at or near saturation levels and inclusive of red and far-red (680 & 700). (e.g. HPS vs MH)

- Photoinhibition and more specifically destructive photoinhibition of PSII via exceeding saturation levels of PPD (relative to photosynthetic activity rate) are likely to cause an increase in Ca utilization in efforts to avert or expedite destructive damage to D1 in PSII. This effect would be most notable with overall high PPD levels above saturation below 700nm. (e.g. HPS > Ca than MH)

- Photoinhibition and more specifically destructive photoinhibition of PSI via exceeding saturation levels (relative to photosynthetic activity rate) are likely to cause an increase, probably large, in Mg utilization as a result of damage to Rubisco, requirement for subsequent synthesis, possible damage to ATP or chlorophyll as well as an effect of Thylakoid stacking in efforts to reduce photoinhibition. This effect would be most notable with high PPD levels above saturation and above 680 nm (e.g. LED)

Just mah 2 cents here I guess xD
 
Joe Fresh

Joe Fresh

1,036
263
shit. :facepalm:

Were you running multiple lights as well (hps, MH)?

Here is pikchurz...

HPS: Leaves only doing this that are closer to light.

View attachment 342956

MH: Same distance leaves. You can see some symptoms but not nearly as bad.

View attachment 342957

I think I am not feeding enough. I am flushing now and gonna hit them with 1.8EC to be sure. Ill know if I made them worse in a couple days. Plants and flowers look healthy. Coco much better than MPB with no signs of bad health whatsoever but coco has been getting lots of food... MPB I've kept around 1.2 EC.
looks like clear salt build up to me cap.....im seeing calcuim deficiency, and lockout....check you rrun off please? i would like to know what the ph and EC is on that run off...and ill let you know for sure if thats your issue
in my experience, hps pushes the plant more, and sympoms show up first under hps



edit....sorry just seen im a bit late to this thread:(
 
Joe Fresh

Joe Fresh

1,036
263
Yeah you know what tripped me out.

Quantrill said under higher light intensities you actually need to feed less. I thought I was wring and asked him to clarify. He clarified.

I need to get at that guy and ask him why, because I have always heard the exact opposite. I figured maybe it was something to do with salt evaporation and leaf scorch.
higher light intensity will have the plant drinking more because it is perspiring more water through transpiration, higher the heat, the more water thats in the plant will be evaporated in the air...higher transpiration rate means the plant will grow faster...wich also correlates to faster transpiration....so your plant will be drinking more water than it will be eating...this means if you keep feeding at the same rate, the plant will eventually not be able to take up everything, leads to salt build up, and that causes a reverse osmotic effect within the plant....it will then use the water moisture within its self, and instead of relocating it towards the leaves, it sends to to the roots to keep them hydrated...leaving your leaves looking like shit(K def, Ca def, leaves taco...ect....).....
 
Junk

Junk

1,754
263
If it is the light, if you swap some lights out, (I think you said you were running a chain of HPS on one side & MH on the other?) or change a couple of the plant orientations to the lights (not sure if it's scrog) given enough time, the problem should repeat itself, but on the other side, no? If someone already mentioned it, I'm sorry, I only read about 5 of the 7 pages.

Then you know it's the light & can narrow it down from there. Or since you already did the measurements, make the intensity the same on both sides & see if that remedies it.

The other thing it looks like to me was mentioned...I think in the first thread you posted about it a while back. Aphids or larvae of some sort. That's the only other time I've seen something that most closely resembled that. If it's strictly on one side of the plants in the whole room, most would rule it out as a mathematical impossibility.

But that's making an assumption that the "possible" invader, isn't just reacting to the light, just like the idea that the nutrients are reacting to it. Perhaps the possible pest likes the hotter side. In my vegetable garden, pests like to be, for the most part, in specific places on specific plants. There is an environmental reason for that. But you could possibly be creating an environmental factor that is causing SOMETHING to gravitate to that side. I don't know if I'm making sense or not.

But you know way more than I ever will, so I'm sure you know if you have aphids or other larva in there. Aphids are pretty easy to find, or at least find traces of. But I've seen that happen where they hang out under the leaves. They don't always leave holes. On my cherry tree the leaves even become yellowish like that, I assume because aphid is sucking nutrition from the leaf. If I get home in time & there are still any aphids left on it, (I'm on vacation at the moment) I will even take a photo so you can see how similar the phenomenon is. It's pretty close. They also seem to prefer the hottest leaves outside here in New England summers, which averages about 80-85 & slightly humid when we got our intruders. Only moving down as the top ones died off.

As I said, I'm sure you know if it's a pest or not, but keep an eye out for ants. Any ants at all. Ants treat aphids like dairy cattle. They will actually herd & farm them because they like to eat the sweet secretions (ugh, tell me that didn't sound gross) of the aphids. It's actually interesting to watch. Just not on my plants. If that happens, first u gotta get rid of the ants, then the aphids. If you are trying to do it organically, it can be a royal pain. Plus, you gotta get rid of them both in certain time frame. Otherwise the ants just come back for the aphids again. I gave up & put sticky traps all over it which was seeming to be effective.

To the original question; I simply added stuff to think about/try. I think you are on to the real problem. I think once you have satisfied that the type of light is the causation, or intensity, I would love to know if you narrow down exactly what deficiency, surplus, disease or pest is causing that. Absolutely fascinated with this one.
 
click80

click80

747
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FWIW.....

Light intensity affects photosynthetic carbon (C) fixation and the supply of carbon to roots. To evaluate interactions between carbon supply and phosphorus (P) supply, effects of light intensity on sucrose accumulation, root growth, cluster root formation, carboxylate exudation, and P uptake capacity were studied in white lupin (Lupinus albus L.) grown hydroponically with either 200 µmol m –2 s –1 or 600 µmol m –2 s –1 light and a sufficient (50 µM P) or deficient (1 µM P) P supply. Plant biomass and root:shoot ratio increased with increasing light intensity, particularly when plants were supplied with sufficient P. Both low P supply and increasing light intensity increased the production of cluster roots and citrate exudation. Transcripts of a phosphoenol pyruvate carboxylase gene (LaPEPC3) in cluster roots (which is related to the exudation of citrate), transcripts of a phosphate transporter gene (LaPT1), and P uptake all increased with increasing light intensity, under both P-sufficient and P-deficient conditions. Across all four experimental treatments, increased cluster root formation and carboxylate exudation were associated with lower P concentration in the shoot and greater sucrose concentration in the roots. It is suggested that C in excess of shoot growth capabilities is translocated to the roots as sucrose, which serves as both a nutritional signal and a C-substrate for carboxylate exudation and cluster root formation.
 
click80

click80

747
63
Im about to do an experiment comparing various LED fixtures, and one of the things I'm interested in learning is how the various spectrums effect cannabinoid profiles. According to some of the LED companies, their profiles are leading to better profiles by allowing the plants to better absorb their required nutrients. I'm supposed to have access to testing labs for my samples, and I'm going compare the profiles from the lab analysis with their spectrum maps and see what can be learned. Its possible we may learn some solid information about how light spectrum effects cannabinoid levels and nutrient absorption.

You might want to go to Pubmed or just google and look into research on this being done with Hops. No measurable difference.
 
EyeC

EyeC

37
18
Throwing my own experiences with light spectrum in i must say that i and others have independently ascertained that, cultivar dependent, ganja is affected in both quantitative and qualitative ways that are light intensity and spectrum dependent. @altitudefarmer having run the same cutting under different light conditions i am convinced that mixing spectrum is the way to turn on as many epigenetic switches as possible. That is at least one reason i don't run glass either. Not blocking UV seems to have a positive effect on terpene formation.

Hortilux Eye Blue and S-HPS are my bulbs of choice and i have been running a 11/13 flowering cycle with very adequate results. No experience with "flow" lighting, but it makes sense intuitively, although i choose 11/13 as i think it strikes a happy medium. Vegetative phase has been either a modified gas lamp schedule most of the time.
Great hearing about others success or failure with different systems. The Gavita's appear to be doing a great job as well i hear.
 
Colossus

Colossus

91
18
shit. :facepalm:

Were you running multiple lights as well (hps, MH)?

Here is pikchurz...

HPS: Leaves only doing this that are closer to light.

View attachment 342956

MH: Same distance leaves. You can see some symptoms but not nearly as bad.

View attachment 342957

I think I am not feeding enough. I am flushing now and gonna hit them with 1.8EC to be sure. Ill know if I made them worse in a couple days. Plants and flowers look healthy. Coco much better than MPB with no signs of bad health whatsoever but coco has been getting lots of food... MPB I've kept around 1.2 EC.


Very similar to how mine looked, throughout, flushing and pHing the water did the job (i also starved them for a day after the flush - Not sure if this is a maximum prison sentence) but they seemed to have loved that and they did react really well to that..... Although i was only using 1x1000w and not many......

Are these Seeds or Clones?
As mine reappeared again during Flower - Im starting to think its a genetic sickness (as mine were clones) and may have been unable to shake that off as generations progress? Just smoked a fat one so obviously give me a minute to resettle! :D
 
Gingergrow

Gingergrow

17
3
I'm a huge fan of simplicity, but I fi had to guess that looks more like a burn than a deficiency on the leaves and that might also explain why it doesn't look so destroyed in the shaded area, or it could be your RH in the tent and veg time usually likes higher temps but in bloom the red light of HPS makes for a fall simulation but that's common sense I've never tried mixing MH with HPS, what are the benefits of that?
 
J

JahLaw

19
3
Plants are autotrophs, creating food through photosynthesis, so to address one comment above, yes...you probably want to feed less at higher light intensities. Remember also, overfeeding can create lock out/nutrient deficiencies! Simple is better, less is more! I have seen great results from blue (FL light) added into a flowering room. A wider spectrum might be beneficial, not enough research on this. You would have to run a controlled test, carefully monitored, and a/b the results. There is so much more research and knowledge for us to do as breeding/seed/nursery companies are jumping the gun. More science, less marketing!
 
jumpincactus

jumpincactus

Premium Member
Supporter
11,609
438
Yeah you know what tripped me out.

Quantrill said under higher light intensities you actually need to feed less. I thought I was wring and asked him to clarify. He clarified.

I need to get at that guy and ask him why, because I have always heard the exact opposite. I figured maybe it was something to do with salt evaporation and leaf scorch.
Cap did this ever get resolved? I realise this thread is a few years ago. Thew reason I ask is when you used your light meter what was the total lux at leaf/canopy surfaces? Keeping in mind that anything over 10,000 lux actually inhibits the process of photosynthesis which in my mind would lend itself to over fertilization due to the inhibited photosynthetic process. Or am I all kinds of way off here. Would seem based on distance from tree with 4000 w of mh/hps you may be blasting the plant with levels in excess of 10,000 lux. Just my 2 cents.

Light Intensity

The intensity of light is important for maximizing the rate of photosynthesis. The optimal light level for photosynthesis is 10,000 lux. Lux is a unit for measuring light intensity. Low light intensity lowers the rate of photosynthesis. However, after reaching an intensity of 10,000 lux, there is no increase in the rate. The rate of photosynthesis may in fact be lowered as chlorophyll is bleached from the chloroplast and the plant’s stomas are closed to slow down water lost through respiration.
 
J

JahLaw

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3
Agree with jumping cactus. You may be well above 10k lux, which would halt photosynthesis dramatically. Great reference.
 
J Bleezy

J Bleezy

8
3
Phosphorus is mobile. So, I'd assume that it would start all around the bottom of the plant, no matter what was causing a phosphorus def.
Sorry if that has already been mentioned, I didn't read everything.
 
Legallyflying

Legallyflying

159
28
Back to the original question..

Cap, I have been doing a bunch of research about light spectrum with the thought of maybe introducing some interior led lights in our vert cages.

We have 2 vert flower rooms (40k) each and will have 4 rooms total in a month or two.

Anywho... from.my research the importance of blie light seems to involve the control.of stomata. It appears that in some species, increased blue light results in increased nutrient uptake and eventual increase in plant biomass.

It seems intuitive that this increase could be attributed to greater transpiration rates due to increased stomata activity... increased water and nute uptake, co2 fixation, etc.

What I am trying to figure out is how much blue light to add....
 

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