Plants self-regulate uptake of ions; they control it, not us, unless we overdo ferts

spurr · Oct 2, 2010

Plants can self-regulate uptake of N, P, Ca, Mg, etc, etc. Thus they control what they absorb by the amounts of certain amino acids in the phloem. For N, plants can not self-regulate uptake of ammoniacal N, which is why ammoniacal N can cause phtyotoxicity (if the plant can't move enough sugar to the roots to convert the ammoniacal N).

The way it works is uptake of nitrate (for example) means increased amino acids in plant because the ions (ex. nitrate) are converted to amino acids inside the plant, thus once a critical level of amino acid is present in phloem the plant will reduce/stop uptake of nitrates. And AFAIK, if one adds too much nitrates to the water they can bypass the plant self-limitation due to osmotic factors, thus causing phytotoxicity.

I am currently study the effects of various mixes of GH flora series ferts upon microbes in aerated compost tea and upon microbes from soil extracts. I am studying the GH mix's of G3h's formula, the Lucas formula and of my own GH formula of 6ml/6ml/6ml (G/M/B) with 5 ml Calmag+, 2.5 ml ProTekt, 5 ml kelp extract and 5 ml hydrolyzed fish. I do not use chem ferts to grow cannabis, but there is much debate about chem ferts effects upon soil biota, thus I hope to get some data and show what is, and is not happening to microbes from application of chem ferts.

Because I use amino acids and proteins from the kelp and hydrolyzed fish (aka fish hydrolysate) I thought I should post some info about how plants can use those sources of DON (Dissolved Organic Nitrogen) directly without microbes breaking them down into ions:

"Nutrient Media for Plant Tissue Cultures"
University of Florida, Horticultural Science Dept.
http://www.hos.ufl.edu/mooreweb/Tiss...Medium%20I.doc

One of the first decisions that must be made when developing a tissue culture system is what medium to use. Nutrient media for plant tissue culture are designed to allow plant tissues to be maintained in a totally artificial environment. Many different tissue culture media have been developed, but only a few have found wide-spread use, e.g. MS (Murashige and Skoog, 1962). SH (Shenck and Hildebrandt), and Gamborg's B5. One of the most successful media, devised by Murashige and Skoog (Murashige and Skoog, 1962) was formulated by analyzing the inorganic components in tobacco plants and then adding them to medium in amounts similar to those found in the plants. Not only did they find that the ions themselves were important, but the forms in which the ions were supplied were critical as well.

In addition to mineral elements, the macro- and micronutrients that are similar to what is found in fertilizers, nutrient media also contain organic compounds such as vitamins, plant growth regulators, and a carbon source.

...

Nitrogen may also be added to medium in an organic form, as amino acids such as proline or glutamine, hydrolysates (such as casein hydrolysate), or, as above, as organic acids. Organic nitrogen is already reduced, i.e. in the form in which most nitrogen exists in the plant, and so may be taken up more readily than inorganic nitrogen. The organic forms are often added to media that do not contain ammonium. However, almost always, some inorganic nitrogen is present.

Guest 18340 · Oct 2, 2010

Per your request I edited the thread, spurr. :tiphat:

ibjamming · Oct 2, 2010

Forgive my ignorance...my botany class was 30+ years ago...

Are ALL essential's picked up that way? By attaching to another molecule? Like hemoglobin for o2 with animals? All amino acids? All different? Does the root hair act like lung avoli (sp)? I need to read more about plants!

spurr · Oct 2, 2010

evlme2 said:
Per your request I edited the thread, spurr.

spurr · Oct 2, 2010

I am not sure what you are asking, I wrote this thread just as a FYI for folks because most ppl do not know plants control uptake of many ions. Many growers think they are in control of what the plant takes in, because they are the ones providing ferts, but that's not the case unless they provide a lot of ions which can bypass the plant regulation and cause phytotoxicity. Many growers think that if they put ions in the water (ex. hydro) the plant will take up the soluble ions no matter what, but that's not the case, plants self-limit uptake via. levels of amino acids in phloem.

Also, of note, is that ammonium (the main type of ammonicial-N ion found in cannabis ferts) will hinder uptake of nitrates. And cannabis, along with many plants, prefer a majority of N to come from nitrates. When ammonium is first taken up by roots it helps uptake of nitrate, but after a few hours the ammonium hinders uptake of nitrates. My hypothesis is that ammonium increases the amino acid level in phloem which triggers the plant to reduce uptake of nitrates.

In general plants, grass and bacteria prefer most N to be nitrate; and trees, shrubs and fungi prefers most N to be ammonium.

Greyskull · Oct 2, 2010

is this why canna suggests using equal parts of their coco A/B thru veg and flower and explain that the plants will take what they need from the nutrient solution?

ive got to look for where i saw it... it was on a site of Canna's i am sure but i dont know if its now a restricted site for me to visit....

spurr · Oct 2, 2010

Greyskull said:
is this why canna suggests using equal parts of their coco A/B thru veg and flower and explain that the plants will take what they need from the nutrient solution?

Not sure, I have not seen that claim, but it sounds like they are referring to what I am writing about. An exception is ammonicial-N, mostly provided by chem ferts as ammonium. Plants can't self-regulate uptake of ammonium. That is why if you add 25 ppm of ammonium and 25 ppm of nitrate to a hydro rez the ammonium will be used to near 0 ppm while nitrates will not (during the same time frame). The plant limits uptake of nitrates but not ammonium. Also, plants can more efficiently/quickly absorb ammonium than nitrates.

Plants must be able to move enough sugar into the roots (from photosynthesis) to convert ammonicial-N (like ammonia NH3- and ammonium NH4-) into useful forms within the roots. If plants can not move enough sugar into the roots fast enough to convert the absorbed ammonicial-N the roots will burn causing phytotoxicity. This is another reason why ammonicial-N makes up only a small fraction of the N in chem ferts. And of that small fraction of ammonicial-N in chem ferts most (if not all) is in the from of ammonium.

ive got to look for where i saw it... it was on a site of Canna's i am sure but i dont know if its now a restricted site for me to visit....

If you find it let us know. :ying:

Greyskull · Oct 2, 2010

i know i read it and i know it was something from Canna ...
it was unique and that why it stick with me... and thats why i was comfortable using a 2 part/1 part food thruout the whole entire grow - becasue the plants ability to pull out what it needs/wants for growth.

I AM ON A MISSION...

spurr · Oct 2, 2010

Greyskull said:
i know i read it and i know it was something from Canna ...
it was unique and that why it stick with me... and thats why i was comfortable using a 2 part/1 part food thruout the whole entire grow - becasue the plants ability to pull out what it needs/wants for growth.

I AM ON A MISSION...

I am looking forward to what you find. You seem to have a very good grasp of this matter, and you and I agree 100%: let the plant take what is wants, don't overfeed :wave:

I wrote a long and very well referenced thread elsewhere a while ago about cannabis tissue assays for nutrients and why less P is needed than is most often used, etc. I could post up some info in a different thread someday if your interested.

Mudita · Oct 2, 2010

interesting to see it stated, but i think i knew it intuitively.
To me that's the whole point of balancing a nutrient solution so that elements are in a proper ratio, and of running lower concentrations. As long as everything is there in ratios that don't cause lockout and within the pH range that doesn't lock anything out, the plant can take what it needs as it needs it.

BTW,I read thru the paper http://www.hos.ufl.edu/mooreweb/TissueCulture/January 22/Media/Medium I.doc
and it does mention that plants can absorb nitrogen in an organic form, but it does not say 'how plants can use them directly without being broken down by microbes first' it only states that they can.

would you please do us the favor of posting up the data concerning precisely how?

spurr · Oct 2, 2010

I promised evlme2 I would not discuss that topic here, I only posted that paper because I wanted to show why I use kelp and hydrolyzed fish for my tests with chem ferts and microbes. Do a search for this thread "Most plants will not die without ions" and check your PMs in a little while, I'll shoot you a message.

Mudita · Oct 2, 2010

I read that other thread, but I was still wondering because it is never said, you two just end up arguing over minute differences in words and it gets boring.

spurr · Oct 2, 2010

Reading the references I uploaded will tell you more than I can in just one post, you will get a much better understanding of the phenomenon and all issues involved by reading the papers. There are a few different routes to absorption. And leafs also absorb organic substances such as dissolved organic nitrogen (from the phyllosphere) as 'food' just like they absorb ions (as 'food') from the phyllosphere through the cuticle layer. I dont want this thread to be about that topic, so here is a post of some of my references that will offer much insight for you, more than I can provide in a single post: https://www.icmag.com/ic/showpost.php?p=3903538&postcount=18

I feel it would be redundant for me to write what those authors already wrote; who probably explain it better than I could too boot because they have a better grasp on it than I do

This is pretty new info, so the science of how it happens is still being worked out.

spurr · Oct 2, 2010

@ Mudita,

Specifically read these papers I uploaded:

"Dissolved Organic Nitrogen and Mechanisms of Its Uptake by Plants in Agricultural Systems"
David L. Jones, John F. Farrar, Andrew J. Macdonald, Sarah J. Kemmitt, and Daniel V. Murphy

"Tansley review: Uptake of organic nitrogen by plants"
Tor gny Nä sholm, Knut Kielland and Ulrika Ganeteg
New Phytologist (2009) 182: 31–48

"Plant Uptake and Utilization of Organic Nitrogen"
Torgny Nasholm
Dept of Forest Ecology and Magagment/Dept of Forest Genetica dn Plant Physuilogy, SLU

"Dissolved organic nitrogen uptake by plants—an important N uptake pathway?"
David L. Jones, John R. Healeya, Victoria B. Willett, John F. Farrar, Angela Hodge
Soil Biology & Biochemistry 37 (2005) 413–423

Mudita · Oct 2, 2010

ok thanks, i was just hoping you'd c&p the info you must already have. I'm not one to do too much digging. I was just curious.

spurr · Oct 2, 2010

I can C&P some info sure, into the other thread in this forum. But I still have to write other posts I promised ppl I would write such as usage of PGRs, etc. I will try to do as you ask by Monday.

Zen Master · Oct 2, 2010

can you put this in doodoo dumb language?

what I'm getting is

"no matter what you feed it, the plant is only gonna take what it wants, not what you force down its gullet"

Greyskull · Oct 3, 2010

found it!!!!

The medium and the plant itself control which nutrients are released to the plant at just the right times.

from Canna's webpage: http://www.cannagardening.com/node/1568?page=0,5
its an "info paper" on their coco product line. unfortunately it doesnt go into detail as to HOW/WHY it works... only that thats whats going on.

heres the whole section from page 6 of article/info paper:

Because CANNA Coco is 100% organic it has a relatively high Cation-Exchange Capacity (CEC). This means the substrate has the ability to hold and retain certain nutrients vigorously thus requiring these nutrients to be supplied in a special form that remains available to the plant.

Due to the special Coco characteristics in combination with the unique pre-buffering process, it is possible to combine vegetative and flowering nutrients in one nutrient mix. The medium and the plant itself control which nutrients are released to the plant at just the right times.
This means the grower doesn’t have to worry about the proper point to convert from grow to bloom nutrients!

discuss....

Carl Carlson · Oct 3, 2010

Greyskull said:
found it!!!!

from Canna's webpage: http://www.cannagardening.com/node/1568?page=0,5
its an "info paper" on their coco product line. unfortunately it doesnt go into detail as to HOW/WHY it works... only that thats whats going on.

heres the whole section from page 6 of article/info paper:

discuss....

Because CANNA Coco is 100% organic it has a relatively high Cation-Exchange Capacity (CEC). This means the substrate has the ability to hold and retain certain nutrients vigorously thus requiring these nutrients to be supplied in a special form that remains available to the plant.

Due to the special Coco characteristics in combination with the unique pre-buffering process, it is possible to combine vegetative and flowering nutrients in one nutrient mix. The medium and the plant itself control which nutrients are released to the plant at just the right times.

According to Argo and Fisher, because of the lack of bulk density, the role of the CEC of soilless media in containers is overblown.

Understanding Plant Nutrition: Nutrient Sources: Media Cation Exchange Capacity

By Bill Argo and Paul Fisher
February 2008

Research has shown that the CEC of soilless media has little effect on resisting change in pH, or in supplying nutrients to the crop. Several experiments were completed at Michigan State University that tested the effect of CEC on long-term pH and nutrition management using impatiens as the test crop. The media tested ranged in buffering capacity from one considered very low (5 meq/liter, a 70 percent rockwool and 30 percent perlite mix) to one that would be considered highly buffered (76 meq/liter, a mix of 70 percent highly degraded consumer grade sphagnum peat and 30 percent perlite).

(Note figure 2 at the link. coir/perlite was also one of the media mixes that was tested)

When shoot-tissue calcium was tested after four, eight, 12 or 17 weeks of growth, there was little difference between plants grown in the media with low CEC (rockwool perlite) or relatively high CEC (consumer grade peat/perlite). The media-CEC therefore did not act as a buffer to nutrient levels available for plant uptake.

Greyskull · Oct 3, 2010

okay.... but what about the plant, itself?

does it eat everything on the plate when we feed it becasue "we are shoving food down its throat"... or does it choose to eat some of the "chicken", some of the "rice", all the "brocolli", and "half the roll, unbuttered" that were made available?

im curious why canna would release to print that "the plant itself control which nutrients are released to the plant at just the right times"... im wondering if theyve tapped into what spurr digging into....

edit: btw nice reference materials Carl Carlson

Plants self-regulate uptake of ions; they control it, not us, unless we overdo ferts

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