Red/Purple veins on my plants

[Bobby86]

Hello everyone I noticed my plants are getting these colors again this year. While they look healthy overall I don't know why these colors are coming in.

Side shot.
 
Happy growing this year everyone I can't wait to see what everyone brings in on 2015.

 

[harry]

The plant produces anthocyanin to protect the stems and veins from various wavelengths of light.

This is a useful trait that I plan on selecting for in a future grow out of an unstable strain here.

 

[Bobby86]

Thanks Harry for this info. I was reading into anthocyanin and not only does it protect as you say but it also gives you a rough estimate on the plants PH.

 

[mikeg]

Thanks Harry for this info. I was reading into anthocyanin and not only does it protect as you say but it also gives you a rough estimate on the plants PH.

What degrees of pigmentation correspond to what ranges of pH? This is very interesting.

The plant produces anthocyanin to protect the stems and veins from various wavelengths of light.

This is a useful trait that I plan on selecting for in a future grow out of an unstable strain here.

Are there similar advantages to more-pigmented phenotypes, such as purple-leaved ornamental C. annuums? Do purple-leaved land-race C. chinense strains like CGN 21500 or Mata Frade have any other advantages?

Would the darker color of purple foliage absorb more heat, causing increased leaf burn under some circumstances? I know it helps protect against UV, outdoors, but i also wonder if it has the same PAR requirements with respect to indoor light.

@Bobby86: Purple streaking of stems and leaves can be a symptom of phosphorus deficiency, but is also a trait that occurs naturally in some specimens of many plant species.
Similarly, pale yellow-green color of apical foliage (young branch-tip leaves) is usually a symptom of "trace-mike" (a.k.a. "trace micronutrients" -- iron, zinc and/or manganese) deficiency... but many strains of Capsicum chinense also feature yellow-tinted apical foliage when healthy.

The plant looks healthy, althought it's coloration could be interpreted as symptoms of both deficiencies. I'd guess that it's perfectly healthy. I may not have enough experience with peppers yet to be 100% certain, but that's my guess.

 

[Bobby86]

@mikeg from the wiki. Anthocyanins can be used as pH indicators because their color changes with pH; they are pink in acidic solutions (pH < 7), purple in neutral solutions (pH ~ 7), greenish-yellow in alkaline solutions (pH > 7), and colourless in very alkaline solutions, where the pigment is completely reduced.[5]

 

[harry]

What degrees of pigmentation correspond to what ranges of pH? This is very interesting.

There is the odd plant that has produced less pigment on the stems and veins than in previous seasons despite exposure to direct sunlight. I hadn't thought much of the fertiliser rotation supplying little by the way of Calcium nutrient since the tap water is hard. In the past I observed too much of white salt precipitating out of solution and forming a layer of scum in the plant saucers.

After noticing that the residue was insoluble in water and unaffected by vinegar I figured it was Calcium sulfate. I took the precipitation of Calcium sulfate as a hint the pH of the mix in various plant pots was on the acidic side due to its increased solubility in acidic solutions. After a couple applications of a teaspon of Calcitic lime one of my red Rocoto plants improved in vigour and now has fresh stems and veins with a hint of purple. This is not a colour shift that you would expect after looking at the photo of pH indicator created from red cabbage on the wikipedia page Bobby linked to (Anthocyanin - Use as pH indicator).
 

Are there similar advantages to more-pigmented phenotypes, such as purple-leaved ornamental C. annuums? Do purple-leaved land-race C. chinense strains like CGN 21500 or Mata Frade have any other advantages?

Would the darker color of purple foliage absorb more heat, causing increased leaf burn under some circumstances? I know it helps protect against UV, outdoors, but i also wonder if it has the same PAR requirements with respect to indoor light.

I have a couple of ornamental Capsicum annuum varieties that produce purple leaves in sunlight. The darkest of the two is the dwarf Ebony Fire chilli cultivar that was bred in Australia. I have seen plants of this variety stand up to >35 °C in direct sunlight.

I had considered obtaining and growing CGN 21500 and Mata Frade to see if it would stand up to the harsh summer conditions here. The most prolific Capsicum chinense varieties here do have some ability to produce anthocyanin that is visible on the stems.
 

@Bobby86: Purple streaking of stems and leaves can be a symptom of phosphorus deficiency, but is also a trait that occurs naturally in some specimens of many plant species.
Similarly, pale yellow-green color of apical foliage (young branch-tip leaves) is usually a symptom of "trace-mike" (a.k.a. "trace micronutrients" -- iron, zinc and/or manganese) deficiency... but many strains of Capsicum chinense also feature yellow-tinted apical foliage when healthy.

The plant looks healthy, althought it's coloration could be interpreted as symptoms of both deficiencies. I'd guess that it's perfectly healthy. I may not have enough experience with peppers yet to be 100% certain, but that's my guess.

I agree that the plant does for the most part appear healthy. The patterned texture of the leaves does hint at the hunger some Capsicum chinense varieties have for Calcium.
 

@mikeg from the wiki. Anthocyanins can be used as pH indicators because their color changes with pH; they are pink in acidic solutions (pH < 7), purple in neutral solutions (pH ~ 7), greenish-yellow in alkaline solutions (pH > 7), and colourless in very alkaline solutions, where the pigment is completely reduced.%5B5%5D

An idea that came to mind is one of us could grow one of the varieties that produces dark purple leaeves and then apply the process used to create pH indicator from the leaves of cabbage but using dark chilli plant leaves. This would require the sacrifice of much of the foliage of an ornamental chilli plant.

 

[mikeg]

Thanks again, Harry. You are very informative.