Purple stems, Anthrocyanins

[Kingrow1]

Just thought id do a small thread on this subject, although confusion for most i think this describes the process for most plants and why we see purple in our plants.



Anthocyanin is the glucoside of anthocyanidin -

https://en.wikipedia.org/wiki/Anthocyanidin

When anthocyanidin combines with sugar it forms the purple pigment anthocyanin. Anthocyanin is increased in plants that are fed high sugar diets.

Leaves of plants can be considered the 'source' of sugar production and roots could be considered the 'sink' as they consume the sugar. A sink can also become a source as its resources/stores are called upon.

The primary job of anthocyanin is to bond with these sugars in a reversible reaction so the sink is not overloaded by the source.

We see seedlings develop purple leaf undersides and stems as the leaves (source) produce more sugar than is needed by the roots. Photosynthesis is often limited by Co2 and not the need for sugar by the roots hence overload can occur.

Anthocyanin is not thought to scavange free radicles and oxygen species.

Increase light will increase photosynthesis past the need of the roots and the link between photoinhibition and root sugar levels.

A general sink to source relationship problem can occur with cold roots as they will not grow as fast as the rest of the plants leaving an excess of sugar that is not used by the root.

We see purple stems from a variety of reasons but im quite sure it corresponds to the sink/source relationship of sugar production within the plant.

When peeps talk about purple in genetics it is more often that a mutant with a weaker sink to source transportation system was selected for breeding and hence the tendency to show more purple colours from this sugar relationship.

Open to discussion or knowledge....

 

[Kingrow1]

Phosphorus deficiency -

So to complete the cycle it is vital to understand the relationship between phosphorus and anthocyanins or purple stems and leaves as it also induces sugar problems within the plant.

The production of sugars during photosynthesis and the conversion of these sugars into energy during respiration enable the plant to perform all other life-functions. When respiration is restricted due to a P shortage, sugars are not converted into energy and they accumulate within the plant tissue. The accumulation of unused sugars leads to the purple coloration often seen with P deficiency. The low energy level within the plants is the underlying cause of the stunted growth typically seen with P deficiency. When energy is low, all plant processes suffer. Flowering and reproduction place a high demand for energy on plants (not to mention the need for DNA in seed production after fertilization). Therefore, adequate P is essential to the process. A plants ability to generate abundant energy becomes more important when it is put under additional stress, such as cold soil and air temperatures.


So we see purple from a P deficiency because sugar cannot be converted to energy and thus builds up in plant material.

 

[DankaDank]

How do cold temps potentiate anthocyanin ?

 

[Kingrow1]

How do cold temps potentiate anthocyanin ?

This is the basic version because its quite complex and the word 'sugar' is a generalization but as ive tried to explain above you have a source of sugar i.e. the leaves where Co2 is split and sugar is made and the you have a sink where the sugar is required i.e. the roots. Should the roots be constricted in growth by lets say the cold we would have a situation whereby the leaves are producing more sugar than the roots can use and hence anthcyanidin joins with sugar as its glucoside producing anthocyanin or that purple colour.

It would be great if the leaves could work in harmony with the roots and im sure that would happen in certain environments but cold seriously impacts that and thus the source to sink relationship becomes imbalanced.

This is all quite new to me so im not trying to perpetuate a certain way of growing but more the processes a plant uses in response to certain positive or negative enviromental factors.

There may be a lot i still dont understand but this my posts above came from the scientific studies available through google search and i have only seen the odd post where someone takes a shot at explaining purple stems etc in its entirety. Hopefully others will validate or potentiate futher understanding as the subject seems to cause quite the confusion and argument.

If you require your own citation on what ive wrote google'ing 'Sink to Source in plants' would get you started.

 

[DankaDank]

Its very interesting topic ,i was visiting a friend in Botrivier (South Africa) and he had a random weed plant growing at the bottom of his garden where there was a sewage pipe with a visible leak (gross i know) the plant was growing in a sewage soil mix ,it looked like any other vegging plant about two feet tall perfectly healthy except the entire plant was dark purple almost black. leaves stem every thing,not a tone of green on it. As for the strain all he ever smokes is swazi (malawi gold grown in swaziland) he often throws his seeds in the garden and the strain is not known for purple qualities ,had a picture but lost my dam sd card.it was truly remarkable never seen any thing like it and its not cold there either. strange strange strange

 

[jarvild]

Okay so lets do discuses this more. So by you're explanation if I were to add Co2 extra lighting and a dialed in grow area I could eliminate purpling in my Purple strains? Never experienced a color change in my purple strains with running co2 and plenty of lighting.

 

[jarvild]

And by their explanation that would mean that purple strains would test higher in brix content than a non purple strain, if as they suggestion of a higher sugar content ?

 

[Kingrow1]

And by their explanation that would mean that purple strains would test higher in brix content than a non purple strain, if as they suggestion of a higher sugar content ?

I dont know if testing for brix would show this, plant sugars come in different forms and i use the word sugar as a generalization as it is by far more complex than my simple write up.

The sugar is joined to the anthocyanidin (of which there is very little info on) as its glucoside so barring a chemist i would be unsure if the brix test would show this or not but guess that if you tested the source (not the sink) yes.

Okay so lets do discuses this more. So by you're explanation if I were to add Co2 extra lighting and a dialed in grow area I could eliminate purpling in my Purple strains? Never experienced a color change in my purple strains with running co2 and plenty of lighting.

No not necessarialy, the extra light could be the cause for source sink sugar build up as could other environmental factors.

Im not here to tell you how to grow better plants dude just discuss the factors that relate to anthocyanin. The application of this knowledge is up to each individual grower and what they deem best. It has already been said a million times to KISS 'Keep It Simple Stupid' and that would be what i advise, however fundamental understanding might allow us to better read our plants situation and that is all.

 

[Kingrow1]

Its very interesting topic ,i was visiting a friend in Botrivier (South Africa) and he had a random weed plant growing at the bottom of his garden where there was a sewage pipe with a visible leak (gross i know) the plant was growing in a sewage soil mix ,it looked like any other vegging plant about two feet tall perfectly healthy except the entire plant was dark purple almost black. leaves stem every thing,not a tone of green on it. As for the strain all he ever smokes is swazi (malawi gold grown in swaziland) he often throws his seeds in the garden and the strain is not known for purple qualities ,had a picture but lost my dam sd card.it was truly remarkable never seen any thing like it and its not cold there either. strange strange strange

Mutations to the genetics of plants can be inbred to give this purple reaction, say we took a plant that had a mutation where its Phot 1 and Phot 2 systems were inactive then blue light sensing would be inaffective in subsequent generations and so forth. Finding these mutations can lead to a whole host of genetic diversity.

A while back scientists found the genes for photoperiod in tomato plants and through certain mutations have now produced a plant that dosent need a dark period as tomatos are very sensitive to photoperiods.

The link below details this -

http://www.latimes.com/science/sciencenow/la-sci-sn-continuous-light-tolerant-tomato-plants-20140805-story.html

 

[jarvild]

I never said you were telling me how to grow. I've been doing it for 40+ years.
But by reading that it seems to sound as if the plant are producing excess sugars when in actuality the plants are producing excess anthocyanin's.
I'M all open for a discussions on plant biology

 

[Kingrow1]

I never said you were telling me how to grow. I've been doing it for 40+ years.
But by reading that it seems to sound as if the plant are producing excess sugars when in actuality the plants are producing excess anthocyanin's.
I'M all open for a discussions on plant biology

No, anthrocyanin is not produced by the plant but anthocyanidin is, the more sugar the more anthocyanidin that joins with the sugar to form anthocyanin.

The same is true to an extent in sugar shortage times some of that anthocyanin can be split to regain the sugar back for plant growth. Quite often those purple stems can be transient or move to wheres needed in the plant.

I can find little in on the study of anthocyanidins so i cannot say much until i have found the relevant studies and papers but this would seem to be how the plant deals with its sugar levels when they surpass the needs.

A leaf will photosynthesise in light wether the plants need the sugar or not as photosynthesis is a light reaction and happens reguardless of plant needs.


I have to put the disclaimer in because some feel like i am trying to tell them how to grow and i do apologise for that confusion.

Realistically its quite a simple system and i will add more to the subject when i get round to it.

 

[Kingrow1]

I would assum anthocyanidin is colourless untill it joins with sugar to produce a purple pigment.

It has also been documented that most higher plants show a certain level of anthocyanin even in peak healthy conditions but it is not visable due to it being masked out by the much stronger and brighter green chlorophyll.

Only in times of imbalance or stress does the anthocyanin show through or cover the chlorophyll in large enough amounts making it visable.

Its quite a delicate system.

 

[jarvild]

Thanks and I appreciate the research. I'm very interested in this because I have a few strain crosses that are to the point of turning almost black by harvest time.

 

[Kingrow1]

Thanks and I appreciate the research. I'm very interested in this because I have a few strain crosses that are to the point of turning almost black by harvest time.View attachment 3627603

Everything i researched was aimed at the veg and seedling stage, flowering is a complex subject and nailing problems down are more complex because sinks become sources and visa versa plus some plant processes are slowing or changing etc etc.

I hope you make some progress and keep working at it till susequent crops do better, it dosent look genetic but more enviromental/nutrient related although it could easily be a combination of the both.

Good luck dude

 

[jarvild]

Not environmental, strain runs great in production just as good as any of my others. Genetics are a cross of Cherry Pie.

 

[Kingrow1]

Not environmental, strain runs great in production just as good as any of my others. Genetics are a cross of Cherry Pie.

Some purple in the genetics combined with the nutes maybe plus them big lights we all use and ph but im sure after a few grows and tweaks somthing might present itself.

I did cover genetics above but your leaves look like more than this, we live and learn dude.

 

[MisterBlah]

Thanks and I appreciate the research. I'm very interested in this because I have a few strain crosses that are to the point of turning almost black by harvest time.View attachment 3627603

Ever since @Kingrow1 posted the thread in the general forum, I started reading more and more on this.

I've found a few things written by a guy named David Hershey(read his koalafications here: http://www.angelfire.com/ab6/hershey/bio.htm)

"In the fall when leaves senesce, they often produce more anthocyanins, which often function to protect the leaves from high light or ultraviolet light.

A similar mechanism might be operating for a nitrogen deficient leaf which is also exporting large amounts of nitrogen. Fall leaf senescence is similar to a leaf nitrogen deficiency because the chlorophyll is no longer being synthesized and mineral nutrients, such as nitrogen, are being exported from the leaf. An older leaf dying from lack of nitrogen is undergoing a similar process. Chlorophyll cannot be synthesized due to lack of nitrogen so the leaf becomes chlorotic, meaning it turns yellow or white as chlorophyll is degraded and the yellow carotenoids are revealed. The nitrogen in the leaf is transported to growing points such as shoot tips, which have a higher demand for nitrogen.

Anthocyanin formation occurs with some other deficiencies, particularly phosphorus and sulfur. Tomato plants often show purpling of their leaf undersides as a phosphorus deficiency symptom. Remember that one thing that may complicate the appearance of leaf anthocyanins in nutrient deficient leaves is whether they are being synthesized in response to a nutrient deficiency or if preexisting anthocyanins are simply becoming visible because of the loss of chlorophyll from the leaves."

So, my understanding is that you are seeing a purple color at the end of the flowering period because the plant in reaching end of life and is no longer producing chlorophyll.

 

[Kingrow1]

Ever since @Kingrow1 posted the thread in the general forum, I started reading more and more on this.

I've found a few things written by a guy named David Hershey(read his koalafications here: http://www.angelfire.com/ab6/hershey/bio.htm)

"In the fall when leaves senesce, they often produce more anthocyanins, which often function to protect the leaves from high light or ultraviolet light.

A similar mechanism might be operating for a nitrogen deficient leaf which is also exporting large amounts of nitrogen. Fall leaf senescence is similar to a leaf nitrogen deficiency because the chlorophyll is no longer being synthesized and mineral nutrients, such as nitrogen, are being exported from the leaf. An older leaf dying from lack of nitrogen is undergoing a similar process. Chlorophyll cannot be synthesized due to lack of nitrogen so the leaf becomes chlorotic, meaning it turns yellow or white as chlorophyll is degraded and the yellow carotenoids are revealed. The nitrogen in the leaf is transported to growing points such as shoot tips, which have a higher demand for nitrogen.

Anthocyanin formation occurs with some other deficiencies, particularly phosphorus and sulfur. Tomato plants often show purpling of their leaf undersides as a phosphorus deficiency symptom. Remember that one thing that may complicate the appearance of leaf anthocyanins in nutrient deficient leaves is whether they are being synthesized in response to a nutrient deficiency or if preexisting anthocyanins are simply becoming visible because of the loss of chlorophyll from the leaves."

So, my understanding is that you are seeing a purple color at the end of the flowering period because the plant in reaching end of life and is no longer producing chlorophyll.

The end of life anthocyanin is somthing ive looked into but havent written about, certain nutrient deficiencies stop the plant converting the sugars to energy or ATP and hence we have a build up of sugar again.

As i said its a vast subject and i will try and cover these points tomorrow when i next get computer access because doing it on my phone is an absolute nightmare (Damn tiny touchscreen keyboard).

 

[jafro daweedhound]

This is the basic version because its quite complex and the word 'sugar' is a generalization but as ive tried to explain above you have a source of sugar i.e. the leaves where Co2 is split and sugar is made and the you have a sink where the sugar is required i.e. the roots. Should the roots be constricted in growth by lets say the cold we would have a situation whereby the leaves are producing more sugar than the roots can use and hence anthcyanidin joins with sugar as its glucoside producing anthocyanin or that purple colour.

It would be great if the leaves could work in harmony with the roots and im sure that would happen in certain environments but cold seriously impacts that and thus the source to sink relationship becomes imbalanced.

This is all quite new to me so im not trying to perpetuate a certain way of growing but more the processes a plant uses in response to certain positive or negative enviromental factors.

There may be a lot i still dont understand but this my posts above came from the scientific studies available through google search and i have only seen the odd post where someone takes a shot at explaining purple stems etc in its entirety. Hopefully others will validate or potentiate futher understanding as the subject seems to cause quite the confusion and argument.

If you require your own citation on what ive wrote google'ing 'Sink to Source in plants' would get you started.

Thanks,
Very well written, you have answered some long standing questions that I have had.

 

[Kingrow1]

Thanks,
Very well written, you have answered some long standing questions that I have had.

Its a complex issue but this is just the process behind it, many factors come into play.

What questions did it answer?