| Title | Responses of nine Trifolium repens L. populations to ultraviolet-B radiation: Differential flavonol glycoside accumulation and biomass production |
| Publication Type | Journal Article |
| Year of Publication | 2000 |
| Authors | Hofmann, R.W., Swinny E.E., Bloor S.J., Markham K.R., Ryan K.G., Campbell B.D., Jordan B.R., and Fountain D.W. |
| Journal | Annals of Botany |
| Volume | 86 |
| Issue | 3 |
| Pagination | 527 - 537 |
| Date Published | 2000 |
| ISSN | 03057364 (ISSN) |
| Keywords | biomass, growth response, physiological response, phytochemistry, ultraviolet b radiation |
| Abstract | This study aimed to quantify and identify flavonoids involved in the response of nine populations of white clover (Trifolium repens L.) to ultraviolet-B radiation (UV-B). Plants were grown for 12 weeks in controlled environment rooms with or without supplemental UV-B radiation of 13.3 kJ m-2 d-1. Methanol-water extractable flavonoids were quantified using high performance liquid chromatography (HPLC). Two major peaks showed significant enhancement in the HPLC chromatogram in response to supplemental UV-B. The structures of the compounds responsible were identified by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy to be the flavonols quercetin-3-O-β-D-xylopyranosyl-(1 → 2)-β-D-galactopyranoside and kaempferol-3-O-β-D-xylopyranosyl-(1 → 2)-β-D-galactopyranoside. With supplemental UV-B, quercetin glycoside levels increased on average by 200% while the kaempferol glycoside response was much smaller. Significant differences in flavonol accumulation were found among T. repens populations, both constitutively and in response to UV-B. Stress-adapted populations displayed particularly high flavonol levels under UV-B. There was an inverse correlation between plant productivity and quercetin accumulation. Furthermore, higher quercetin accumulation under UV-B was correlated with tolerance against UV-B-induced growth reduction. In conclusion, within-species comparisons in T. repens lend support to a distinct role for ortho-dihydroxylated flavonoids in the adaptation to UV-B stress and suggest particular advantages in this UV-B-induced biochemical adaptation for populations characterized by low habitat and plant productivity. (C) 2000 Annals of Botany Company. |
| URL | http://www.scopus.com/inward/record.url?eid=2-s2.0-0033831616&partnerID=40&md5=18531be84d5d46f60ba8cb7a0db68425 |
| DOI | 10.1006/anbo.2000.1216 |
