Additional phosphate stabilises uninterrupted growth of a Dioscorea deltoidea cell culture.

Suspension cells of Dioscorea deltoidea Wall (strain D-1) were maintained in a semicontinuous culture (SCC) in shake flasks at a high growth rate. It was shown that continuous propagation growth of this culture is unstable on Murashige's and Skoog's (MS) medium due to P starvation. On a P-enriched MS-medium the SCC was stable even at mean specific growth rates >0.3 day(-1). Highest volumetric concentrations of furostanol glycosides were obtained, when a P-enriched SCC was not further subcultivated but fed with sucrose. The investigated culture is able to control phosphate uptake and to prevent toxicity on media with excess P. High concentrations of cellular P(i) did not effect the ratio of furostanol to starch.