In vitro-cultured plantlets of Vitis vinifera L. Cv malbec respond to UV-B radiation by increasing membrane â-sitosterol

GIL M; PONTIN M; BOTTINI R; PICCOLI P

BIOCELL

INST HISTOL EMBRIOL-CONICET

Lugar: Mendoza, Argentina; Año: 2010 vol. 34 p. 48 - 48

0327-9545

The scientific literature reports that the ultraviolet-B (UV-B, 280- 320 nm) radiation affects plant secondary metabolism differently according to fluence rate, dose, and wavelength of the UV-B treatment. Plant membranes possess complex sterol profiles that reinforce the membrane cohesion, dominated by sitosterol and stigmasterol. This work studied the UV-B effect on sterol composition in grape leaf tissues. Plantlets of 45 days-old grown under a photosynthetic active radiation (PAR) of 100 ìmol m-2 s-1 without UV-B were exposed during 16 h to the same PAR with two UV-B dosis: 0 (control), and 4.75 kJ m-2 d-1; the UV-B dose was administered at two intensities: low UV-B (8.25 ìW cm-2 during the 16h photoperiod) or high UV-B (33 ìW cm-2 during the 4 final h of the period). Methanol: chloroform (1:1) extracts were analyzed by gas chromatography coupled to mass spectrometry. â-sitosterol content was significantly increased under both UV-B treatments, although this effect was more noticeable under low UV-B. These results suggest that UV-B-induced sitosterol synthesis is dependent from both, the UV-B intensity and the UV-B dose.ìmol m-2 s-1 without UV-B were exposed during 16 h to the same PAR with two UV-B dosis: 0 (control), and 4.75 kJ m-2 d-1; the UV-B dose was administered at two intensities: low UV-B (8.25 ìW cm-2 during the 16h photoperiod) or high UV-B (33 ìW cm-2 during the 4 final h of the period). Methanol: chloroform (1:1) extracts were analyzed by gas chromatography coupled to mass spectrometry. â-sitosterol content was significantly increased under both UV-B treatments, although this effect was more noticeable under low UV-B. These results suggest that UV-B-induced sitosterol synthesis is dependent from both, the UV-B intensity and the UV-B dose.-2 d-1; the UV-B dose was administered at two intensities: low UV-B (8.25 ìW cm-2 during the 16h photoperiod) or high UV-B (33 ìW cm-2 during the 4 final h of the period). Methanol: chloroform (1:1) extracts were analyzed by gas chromatography coupled to mass spectrometry. â-sitosterol content was significantly increased under both UV-B treatments, although this effect was more noticeable under low UV-B. These results suggest that UV-B-induced sitosterol synthesis is dependent from both, the UV-B intensity and the UV-B dose.ìW cm-2 during the 16h photoperiod) or high UV-B (33 ìW cm-2 during the 4 final h of the period). Methanol: chloroform (1:1) extracts were analyzed by gas chromatography coupled to mass spectrometry. â-sitosterol content was significantly increased under both UV-B treatments, although this effect was more noticeable under low UV-B. These results suggest that UV-B-induced sitosterol synthesis is dependent from both, the UV-B intensity and the UV-B dose.ìW cm-2 during the 4 final h of the period). Methanol: chloroform (1:1) extracts were analyzed by gas chromatography coupled to mass spectrometry. â-sitosterol content was significantly increased under both UV-B treatments, although this effect was more noticeable under low UV-B. These results suggest that UV-B-induced sitosterol synthesis is dependent from both, the UV-B intensity and the UV-B dose.â-sitosterol content was significantly increased under both UV-B treatments, although this effect was more noticeable under low UV-B. These results suggest that UV-B-induced sitosterol synthesis is dependent from both, the UV-B intensity and the UV-B dose.