What's in a flower?
Specifically hydrangea flowers. In this post I pointed out that anthocyanin (a family of plant pigments) appears blue at high pH, red at low pH and is responsible for the wide variety of colours in hydrangea flowers. Ilona pointed out that , "in hydrangeas you lower the ph for blue flowers (more acid) and raise it for pink (more alkaline)." I did a bit of checking and found that this is the case . At lower soil pH hydrangea flowers do appear blue and at higher soil pH they appear red. But soil pH is not the only thing that affects the colour of hydrangea flowers. It appears that pH inside the plant cell has an affect as well: Sepal Color Variation of Hydrangea macrophylla and Vacuolar pH Measured with a Proton-Selective Microelectrode Anthocyanin changes its color depending on pH (Goto 1987, Brouillard 1988, Goto and Kondo 1991). In strong acidic conditions it shows red, in neutral, purple and in alkaline, blue. But generally the vacuolar pH of plant cells is weakly aci
Beautiful version of a wonderful song! Thanks for getting my Ash Wednesday off to a good start. :)
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