Abstract:

【Objective】 To investigate the effects of riboflavin on phenylpropanoid metabolism in tobacco cells. The activity of phenylalanine ammonia-lyase (PAL) and peroxidase (POD), accumulation of phenolic compounds and lignin were determined. 【Method】 Tobacco suspension cells treated with 1 mmol?L-1 riboflavin were used to investigate the effect of the phenylpropanoid metabolism by biochemical, cytochemical and HPLC (high performance liquid chromatography) analysis. 【Result】 The activity of PAL and POD increased and reached the highest level at 12 h and 24 h after treatment with riboflavin, respectively. The observation of bright blue fluorescence indicated that more phenolic compounds accumulated in the cells under UV light, extracts from tobacco cells and their culture filtrate showed strong accumulation of scopoletin within 48 h after treatment, and reached a peak at 12 h after treatment. Lignin deposition strongly increased by 1.5 and 1.8 times respectively at 24 and 48 h after elicitation when compared with the control. 【Conclusion】 These results suggest that the increase in related enzymes, phenolic compounds and lignin was induced by riboflavin in tobacco suspension cells.

Key words: tobacco')">tobacco, riboflavin, phenylpropanoid metabolism, scopoletin, lignin