Abstract
The sepal color of Hydrangea macrophylla changes easily depending on environmental conditions. The most interesting phenomenon of the color development of hydrangea is that the same components (delphinidin 3-glucoside, 3-acylquinic acid, 5-acylquinic acid, Al3+) develop a variety of sepal colors from red through purple to blue. Recently we found that in purple colored sepals of hydrangea red, purple, and blue colored cells coexist. To clarify the mechanism of cell color variation in purple colored sepals we prepared protoplast mixture of various colored cells. We recorded an absorption spectrum of a cell, vacuolar pH, composition of the anthocyanin and the co-pigments, Al3+ in the each colored cell. Between the color and vacuolar pH no correlation was observed. The bluer the cell, the more the amount of 5-acylqunic acid increased. The sepal color might be affected by many factors, such as pH, somposition of co-pigment and Al3+.
