1. Dynamics of flavonol accumulation in leaf tissues under different UV-B regimes in Centella asiatica (Apiaceae).
- Author
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Bidel LP, Chomicki G, Bonini F, Mondolot L, Soulé J, Coumans M, La Fisca P, Baissac Y, Petit V, Loiseau A, Cerovic ZG, Gould KS, and Jay-Allemand C
- Subjects
- Apiaceae radiation effects, Plant Leaves radiation effects, Apiaceae metabolism, Flavonols metabolism, Plant Leaves metabolism, Ultraviolet Rays
- Abstract
Main Conclusion: A cumulative effect of UV-B doses on epidermal flavonol accumulation was observed during the first week of a time course study in Centella asiatica (Apiaceae). However, once flavonol levels had peaked, additional accumulation was possible only if higher daily UV-B irradiances were applied. We aimed to understand the dynamics of flavonol accumulation in leaf tissues using non-destructive spectroscopy and HPLC-mass spectrometry. When leaves that had grown without UV-B were given brief daily exposures to low-irradiance UV-B, they accumulated flavonols, predominantly kaempferol-3-O-β-D-glucuronopyranoside and quercetin-3-O-β-D-glucuronopyranoside, in their exposed epidermis, reaching a plateau after 7 days. More prolonged UV-B exposures or higher doses eventually augmented flavonol concentrations even in non-exposed tissues. If UV-B irradiance was subsequently reduced, leaves appeared to lose their ability to accumulate further flavonols in their epidermis even if the duration of daily exposure was increased. A higher irradiance level was then necessary to further increase flavonol accumulation. When subsequently acclimated to higher UV-B irradiances, mature leaves accumulated less flavonols than did developing ones. Our study suggests that levels of epidermal flavonols in leaves are governed primarily by UV-B irradiance rather than by duration of exposure.
- Published
- 2015
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