Effects of sucrose concentration on the accumulation of anthocyanins in grape (Vitis vinifera) cell suspension

A cell suspension of Vitis vinifera L. cv. Gamay Frédaux var. teinturier composed of 50% pigmented cells was grown in Gamborg B5 medium supplemented with (per litre) 250 mg casein hydrolysate, 0.1 mg α-naphthalenacetic acid, 0.2 mg kinetin, and either 20, 30, 50, or 60 g sucrose. In the presence of 20 and 30 g sucrose/L, growth of cells was characterized by a typical sigmoid pattern and maximum cell density was obtained in 30 g sucrose/L. In both media, the anthocyanin content of pigmented cells did not change significantly throughout the growth cycle. In the presence of 50 g sucrose/L, cell growth was characterized by an extended lag phase. During this period, there was a significant (P < 0.05) accumulation of anthocyanins in the pigmented cells. Browning of the medium and premature cell death was observed in medium with 60 g sucrose/L. Microscopic observation of the suspension revealed the occurrence of anthocyanoplasts, especially in anthocyanin-containing cells cultured in 50 g sucrose/L. In some instances anthocyanoplasts were observed in cells with nonpigmented vacuoles, thus supporting the thesis according to which anthocyanoplasts would be the site of anthocyanin synthesis.