Abstract
The present study was carried out to clarify the effect of sodium molybdate on changing the flower color of balloon flowers, Platycodon grandiflorum A. DC. cv. Samidare.
When the cut flowers were held in the Mo solutions (0, 2.5, 5 and 10mM), the flower color change from blue-violet to blue was enhanced with increase of Mo concentration. Spraying of Mo solutions (0, 2.5, 5, 10 and 20mM) to the flowers of potted plants had bluing effect similar to the case of Mo uptake by the cut flowers. Damage of the plants from Mo treatments appeared at the concentrations of 10mM in the former and 20mM in the latter.
Main absorption maximum of the fresh petals of cut flowers held in the Mo solution shifted toward a longer wavelength and increased in absorbance. Similar spectral change was exhibited upon in vitro addition of molybdate ions to anthocyanin solution. This bluing effect due to Mo addition decreased with subsequent addition of a chelate agent, EDTA.
The bluing of balloon flowers caused by Mo uptake seems to be due to the formation of metallo-anthocyanin in pigment cells.
