Enhancement of Anthocyanin Accumulation by High Osmotic Stress and Low pH in Grape Cells ( Vitis hybrids)

Abstract

A cell suspension of grape (Vitis hybrids) was cultured under various osmotic stresses and various pH values of the medium. When cells were cultured under osmotic stress, total anthocyanin accumulation increased with increasing concentrations of D-mannitol, up to 0.4 M. Anthocyanin content per cell was also enhanced with increased osmotic stress as was the proportion of pigmented cells to non-pigmented cells. Cell growth was repressed with increased media osmolarity. Anthocyanin production was also affected by pH in the medium. Low pH (PH 4.5) in the media caused more anthocyanin production than neutral pH (PH 7.0). Both cell growth and anthocyanin content were decreased according to increasing pH. This result is in contrast to the case of osmotic stress. The mechanism of induction of anthocyanin synthesis might be different between the case of various pH values and the case of osmotic stress.