thank you! I feel much better now! Many thanks!!

I just read about anthocyanin pigment: it changes its color accordingly to PH it gets in contact. It's red when PH is low and goes blue when PH is high. So a purple color should mean a neutral PH, according to the article. Do you think in plants it's related to environment?

Was the article about hydrangea flowers by chance? Because that has to do with uptake of metals from the soil (aluminum) that occurs particularly at lower pH's and turns the flowers blue. Doesn't apply to daylilies. As far as I'm aware the "pink socks" in daylilies occur whatever the soil pH. Cell pH is another question. Can you post a link to the article?

Temperature can also affect anthocyanin pigment. @admmad would be the person to ask about this.

Edit: no I mis-read and am misleading you, hydrangea flowers are blue at low pH and pink at high pH and sort of muddy purply-pink in between so your article obviously was not about hydrangeas. Sorry.

I cannot link the article cause it's in italian!
It was a scientific experiment for children. It was about boiling a red cabbage to extract the anthocyanin pigment, then using this juice adding in different containers different substances such as vinegar, citric acid, or baking soda to see how the color of the pigment changes reacting to different PH values.
I know about hydrangea but it's the opposite. Wondering now what colors hydrangeas.

Google does a pretty good job of translating.

Ok! here it's the article!
http://bressanini-lescienze.bl...

Sounds like we might should be eating purple tinted daylily stems.