Polyphenol synthesis in cell suspension cultures of Paul's Scarlet rose

1. In dark-grown cell suspension cultures of Paul's Scarlet rose (Rosa sp.), polyphenol accumulation is essentially restricted to late- and post-exponential phase cells. The range of polyphenols synthesised is extensive, involving at least fourteen different compounds which show a characteristic pattern of development over the growth cycle. 2. The duration of polyphenol accumulation is largely determined by the availability of carbohydrate, while the initiation and initial rate of synthesis is largely influenced by a complex of factors of which auxin concentration and light are most important. High 2,4-D concentrations (5x10(-5)M) supress accumulation by delaying initiation and reducing the subsequent rate of synthesis. High intensity illumination (6000 Lux) partially reverses the inhibition of polyphenol synthesis at 5x10(-5)M 2,4-D, and enhances accumulation at lower auxin concentrations (5x10(-7)M 2,4-D). 3. Illuminated cultures also accumulate anthocyanin. Initiation of pigment synthesis is insensitive to the auxin concentration of the medium, and higher hormonal levels (5x10(-5)M 2,4-D) increase net anthocyanin accumulation by prolonging the period over which it is synthesised.