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Schnitzler, J.-P. ; Jungblut, T.P. ; Heller, W. ; Köfferlein, M. ; Hutzler, P. ; Heinzmann, U. ; Schmelzer, E.* ; Ernst, D. ; Langebartels, C. ; Sandermann, H.

Tissue localization of UV-B-screening pigments and of chalcone synthase mRNA in needles of Scots pine seedlings.

New Phytol. 132, 247-258 (1996)
DOI
Open Access Green as soon as Postprint is submitted to ZB.
Epidermal tissue was isolated from Scots pine (Pinus sylvestris L.) needles by enzymatic digestion in order to study tissue distribution of u.v.-B-screening pigments. Up to 90% of the needle content of a group of diacylated flavonol glycosides that were structurally closely related was found in the epidermal layer. Among these metabolites, 3 '',6 ''-di-para-coumaroyl-isoquercitrin and 3 '',6 ''-di-para-coumaroyl-astragalin were the main u.v.-B-induced compounds in cotyledons and primary needles, respectively. However, catechin and astragalin (kaempferol 3-glucoside), two non-acylated flavonoid metabolites, were only observed in total needle extracts, and at levels independent of u.v.-B treatment. According to this metabolite distribution, the mRNA of chalcone synthase, the key enzyme to flavonoids, was found in epidermal and mesophyll as well as vascular tissues. The major alkali-extractable wall-bound phenolic metabolites, astragalin, 4-coumaric acid, and ferulic acid, a minor component of the cell wall, were also found exclusively in the epidermal layer. These compounds were not stimulated by u.v.-B irradiation within the experimental period. Staining of needle cross sections and epidermal layer preparations with Naturstoffreagenz A confirmed the specific localization of wall-bound astragalin in the outer wall of the epidermal layer. Model calculations of u.v.-B absorptions at 300 nm of soluble and cell-wall-bound metabolites of the epidermal layer revealed an almost complete shielding of the mesophyll tissue from u.v.-B radiation.
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Publication type Article: Journal article
Document type Scientific Article
Keywords Pinus sylvestris (Scots pine) seedlings; epidermal layer; uv-B irradiation and flavonoid localization; chalcone synthase; in situ hybridization; ULTRAVIOLET-B; HIGHER-PLANTS; RADIATION; BIOSYNTHESIS; LIGHT; PHOTOSYNTHESIS; PENETRATION; SYLVESTRIS; RESPONSES; ELICITOR
ISSN (print) / ISBN 0028-646X
e-ISSN 1469-8137
Journal New Phytologist
Quellenangaben Volume: 132, Issue: 2, Pages: 247-258 Article Number: , Supplement: ,
Publisher Wiley
Reviewing status Peer reviewed
Institute(s) Institute of Biochemical Plant Pathology (BIOP)
Institute of Pathology (PATH)