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Yellowing is not neccessarily a lack of N.

MrFista

Active member
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Organic Chemistry for the Organic Fanatics

Organic Chemistry for the Organic Fanatics

We know the plant is scavenging chlorophyll. What is chlorophyll - chlorophyll a is the universal primary photosynthetic pigment, it is:

C55H72O5N4Mg

Other forms of chlorophyll have differing carbon, hydrogen and oxygen numbers, but unless they have weaker structures it doesn't matter. The N and Mg are the same.

We can discount the carbon, hydrogen and oxygen as being of any real nutritional worth for scavenging leaves. Why? Leaves are responsible for producing sugars made of these elements. You wouldn't bust up the sugar factory to get more sugar. We'll revisit these soon.

That leaves nitrogen at 6.31% of the mass of chlorophyll a, and magnesium at 2.72% of the mass of chlorophyll a.

So this sounds good right? There's N and Mg for the taking. True. But it's not easy to get at. Surrounded by a network of bonds, the magnesium and nitrogen are at the centre of unsaturated ring structures with lots of double bonds. Double bonds will typically undergo addition reactions (taking new molecules on) rather than elimination (losing bits and thus degrading a bit).

Take a look at the molecules scroll down to half page here http://en.wikipedia.org/wiki/Chlorophyll

It's clear the N is no easy target.

Now take a look at nitrate and the surrounding reactive (charged) oxygen atoms.

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

And ammonia (left hand side at top)

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

And arginine

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

Chlorophyll seems to be a very expensive source of N when looking at molecules it could be sourced from and the loss of a plants photosynthetic ability (and source of energy) that accompanies using it.

I want to read about the strain on the root system after stretch and N transporters diminishing. But alas, it is still in French.
 

VerdantGreen

Genetics Facilitator
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cool stuff mr F. it will take me a while to digest. as you say each strain would have it's own idiosyncrasies when it comes to yellowing/senescence.

i will check the roots of the plant in the photo but i suspect rootbinding will not be a problem (i repotted it as it went to flower) so much as it ran out of N and other nutrients. this would be an example of one that yellowed a little too early.
you can see in this photo taken at around 5 weeks - under halfway through - that the centre area leaves (which of course corresponds to the lower leaves in a straight up plant) are already starting to yellow. it did get fed in addition to that and the yellowing slowed down enough.
the green plant didnt start to yellow at all until a week or two from harvest.
picture.php


as for what is too early and ideal i would agree there is a compromise to be had between yield and quality. i would say that about 75%- 80% of the way through flowering is when i would be 'pleased' that the plant had started to yellow. just a theory, but i suspect that once leaf senescence and the nutrient recycling process is triggered, it can actually have a positive effect on bud growth, giving a nice late swelling that wouldnt otherwise have been so pronounced.

now i need to look at your 'science bit' again and read the links :)

p.s. i say you should approach the hot french girl for help with translation, ya never know, she may even fumez le shit :D or at least you could buy her a coffee.

cheers

VG
 
C

Carl Carlson

Hi all.

I'm on my second run with no fertiliser inputs and the plants are dark green and pumping away. The last run in flower showed senescence - leaves yellowing nearer the base of the plant and some dropping off eventually.

I have read here so many times than yellowing of leaves in flower signifies N is running low and the plant is using the N in the leaves, and not to top the N up as the plant is now in flower....

Ahem. Bullshit.

There is certainly no lack of N in my soil. I pulled those senescing plants out and planted some more 3 weeks later and they vegged really fast and now they're flipped to flower and are deep green.

The plant yellowing happened with plenty of N left in the soil. Senescence is not a symptom of lack of N when in flower, though a shortfall will provide conditions for more severe senescence.

great topic, great thread.

I check it out yesterday and today read some things in Teaming with Microbes that seem go with what you've observed.

However, I have to ask if you in part

I think it would be entertaining to move this thread to the chem growers forum and see what happens.

and you

are referring to the school of chem growers that stop feeding N at the onset of budding and than wonder why a week later the lower leaves are yellow. I could be wrong, but don't think that is senescence.
 

Mr. Greengenes

Re-incarnated Senior Member
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Isn't this a great thread? I keep my mouth shet and cheerlead, sometimes post a pic or two. BTW, sorry if you all have seen this pic before but it's one of my faves! It's a W. Wizard leaf.

album.php
picture.php


Ok then, how about a W.W. bud?
picture.php
 

Microbeman

The Logical Gardener
ICMag Donor
Veteran
great topic, great thread.

I check it out yesterday and today read some things in Teaming with Microbes that seem go with what you've observed.

However, I have to ask if you in part



and you

are referring to the school of chem growers that stop feeding N at the onset of budding and than wonder why a week later the lower leaves are yellow. I could be wrong, but don't think that is senescence.

Why would it not be? Before I wisened up I followed all the myths regarding pH and fertilizer manipulation, thinking myself a master grower blah blah and all that BS. It was not until I 'really' observed plants growing naturally that I realized I was just spinning my wheels and although I was providing ionic nutrients to the plants and mostly screwing them up, they were growing, following their genetic/environmental pattern DESPITE what I was doing to them.
 

MrFista

Active member
Veteran
I like the leaf photo best! When the chlorophylls are used up the other pigments, already in the leaves, begin to show through.

I have since determined the chlorphyll MUST be broken down in their own cells as they are simply too big a molecule to be soluble. Anything more than 5 carbons is hard to move unless there is an ionic polar bond in the functional group. Although this does exist in the centre as Mg-Cl-Mg... 55 carbons is well oversized. Even the arginine seems a little big (6 carbons), though only just so, and with polarity at both ends of the molecule may well be soluble. The interesting thing about arginine is that it increases the solubility of some other compounds including those with aromatic (think rings with double bonds like you see in the chlorophyll) structures (perhaps chunks of that big chlorophyll molecule for instance).

I have senescing just beginning on the first five leaves at the base of my plants. 2 weeks into flower. The plants are still deep green, suggesting there is no shortage of N. These leaves are 3 foot below the canopy, completely shaded, and are juvenile organs*. I had to get in under and peer around to find them. Watching closely.

I need to N test this soil now to prove it doesn't lack N. I can check for ammonia nitrite and nitrate, but will miss loads of it that is tied up in the microherd. Still, I only need to find some. I hope the testing works I'll be using water test kits on runoff. I'll sit the soil in with some neutral water, shake the crap out of it, let it settle, then take some runoff. If anyone knows a nitrogenous compound test for soils that is cheap, speak up now please.

*Plants undergo juvenile vegetative, adult vegetative, and adult flowering, sometimes all three on the same plant at the same time (not heard of this in MJ, yet). The leaves at the base of a plant remain juvenile throughout their lives.

Farewell my first wee 5 leaves, you've served me well.
 
S

schwagg

MM, is there a way to see organic N? or total N(organic and available)?
 

nukklehead

Active member
Dont know much about the science/chemistry part but I have always grown organic soil with minimal nutes. Different strains seemed to yellow at different times. I use to worry about it but back in the day of OG there was a knowledgeable dude named mello yello and all of his yields/grows were extremely yellow during mid late flower/harvest.
Therefore, know your genetics, know your soil, dont worry about yellowing in the long run:good:
 

MrFista

Active member
Veteran
Your simple N test will likely not reveal organic N; just available N

That's OK. I don't expect any accuracy, just hope some N can be detected in the soil with this method. The ions are all soluble so in theory I should be able to get a yes no answer on N being present.

Method. A 1/2 inch interior diameter pipe was inserted into soil to 12 inches depth in four seperate positions on bed to gain soil core samples. It only collected about 4 inches per attempt, this was plenty. I took the first two samples from the surface (mulch removed) and burrowed down a bit in two spots to get a centre and base sample as well.

All soil samples mixed in same jar, 50 ml water added, contents then shaken for 3 minutes. Left to sit in dark for 1 hour to settle. Excess liquid drained off carefully and tested for ammonia, nitrite, and nitrate.

More in next post.
 

MrFista

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Veteran
The results are in.

The results are in.

All three forms of nitrogen tested for gained a positive result. Very clear results in the tests with the control of the water testing 7.0 pH; and 0, 0 and 0 for ammonia nitrite and nitrate respectively.

Runoff was filtered though a lemon squeezer with a cheesecloth then coffee filter layered insert.

Tests:

Ammonia/Ammonium (NH3/NH4+) ~ 4 ppm

Nitrite (NO2-) < 0.50 ppm

Nitrate (NO3-) > 160 ppm.

Only had enough runoff for one round of tests so the numbers aint great. Wasn't going to do more. I hated coring into my 'no till' bed. Stressed me out. :gaga:

Worth it though. Considering all I wanted was a yes/no answer I found all three species easily. I'll do it again near end of flower when senescence is obvious.

:jump:
 

MrFista

Active member
Veteran
I'll keep watching the plants close for more obvious senescence. Last run of this strain showed orange, red purple and yellow combos of hues throughout the canopy as it finished - lovely, hope it performs for me again. At the moment from viewing the plants they look like they got loads of N. Funny, cos I haven't put any in.

Wee bit of light bleaching though - oops! So easy to look after (water once per week) they sneak up on ya.

Now I'll wait for flowers and put nothin but a worm castings tea in to help them. There's a billon workers in the Rhizocity, the N cyclers are just some of them.


Proof to me, how about you?

A deficiency of N is not responsible for senescence. N is there in the soil after one run that senesced in it and is now into the flowering of a second run. Please do this test for yourself on an organic bed or outdoor plot of your own when your plants are senescing and you too will see that available ionic N is present in the soil in several forms. All you need is an aquarium test kit for pH, ammonia, nitrite and nitrate; a 1/2 inch pipe; a stick to jam in the pipe and get the dirt out; a jar; 50 ml water, another jar, cheesecloth and coffee filter. And a shaking arm.

Adding N to soil is a waste of nutrients after a certain point, where is that point?

Imagine if I put more N in an entire grow ago, the yellowing comes early so I hone in on the bullshit mantra - more N in (1st two weeks of) early flowering if yellowing starts as it's in short supply.
 

MrFista

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Did a bunch of math. I figure that's (very) roughly 7.5 grams N available at that snapshot in time in the bed entire. Sounds like a shortage? Err, no. That's just the ionic forms the microbes are releasing after eating other microbes. I don't put ionic nutes in this soil, the critters are key to what's going on and they'll keep doing the things they do including cycling forms of N.

The N's gotta come from somewhere. Are there symbionts fixing N with only weed growing there? Is the 3 years recycled soil with char and mulch now supporting a microherd with members that fix N? How much of these soil cycles do we disconnect when we till? I'll continue to add mulch only, no blood n bone or lime or anything at all till yield suffers or deficiencies show up.

I do add minimalist type teas. 3 per grow, veg, transition, flower.

4 gallons pond water, 2 cups worm castings, 2 tsp molasses, 10 ml kelp, 5 ml fulvic, 5 ml humic, pinch sea solids.

Transition add 1/4 tsp high p guano. Flower do the same. ==>>> Heavy nute regime.
 

Microbeman

The Logical Gardener
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Nice work Mr Fista. I've been away for a couple days fighting a war against Roundup.
 

guest2012y

Living with the soil
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I should say I'm out here paying attention and find this pretty interesting Fista..cool stuff as usual.
(MM...How many parts per million does every living human being on Earth have of Roundup in their bodies?....I forgot.)
 

MrFista

Active member
Veteran
Thanks MM I appreciate the feedback. I am so sick of my lecturers banging on about fertilisers and chemical solutions and GE... I sometimes feel like I'm wasting my time at university but being able to do something like this shows it is definately helping me in my understanding and exploration of many things.

I always did love Mythbusters and I got to do a bit of mythbusting myself. Thoroughly enjoyable. Do you get the mythbusters show in US? Two science geeks examining old wives tales for the truth in them. Great show.

Off to do some fungi reading now. The arginine supplied by the fungi has been implicated as a precursor for polyamines involved in organ development and cell expansion. A lot of cell expansion takes place in stretch...

Only certain plants possess the enzyme arginase. Methinks it might be plants associated to a specific fungi... Arginase breaks arginine into urea and ornithine. Other plants produce ornithine to make polyamines, the arginine pathway is special and the products it supplies are useful for boosting mitochondrial numbers. When those leaves get broken down there's a lot of sugar reducing to be done. The mitochondria will have plenty to do.
 

hash head

Member
Nice work Mr Fista. I've been away for a couple days fighting a war against Roundup.
monsanto is evil..


agent orange... roundup gmo, suicide genes.. fucking with third world countries and everyone..


they want to own the rights to seeds all food seeds, they also like making resistant strains of weeds to roundup, and instead of farming smart.. they just make people use more water and more and more fucking roundup..

I hate them with a passion.. they are one of the true evils in this world.
 

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