REGULATION OF ANTHOCYANIN AND LIGNIN SYNTHESIS IN PETUNIA-HYBRIDA CELL-SUSPENSIONS

In Petunia hybrida cv. Violet 30 cell suspensions the phenylpropanoid pathway can be induced to produce lignin and anthocyanins. Orthovanadate addition leads to lignin accumulation, subculturing the cells using small inoculum sizes (< 2 g fresh weight 1(-1)) gives rise to both anthocyanin and lignin production. Orthovanadate has a negative effect on cell growth. By replacing the medium, one day after orthovandate additon, by medium without elicitor, we were able to restore growth without disturbing the lignin accumulation. The activity of phenylalanine ammonia-lyase (PAL) increased immediately after orthovanadate addition; this increase stopped upon medium replacement without affecting the lignin production. Reduction of the NAA concentration from 2 mg 1(-1) to 0.1 mg 1(-1), subsequent to the elicitation by orthovanadate or dilution stress, gave rise to a further increase in the production of lignin and anthocyanins respectively. Decreasing the NAA concentration without a prior elicitation, didn't have any effect on either PAL activity or product formation.