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Localization of Phenolics in Phloem Parenchyma Cells of Norway Spruce ( Picea abies )
Author(s) -
Li ShengHong,
Nagy Nina Elisabeth,
Hammerbacher Almuth,
Krokene Paal,
Niu XueMei,
Gershenzon Jonathan,
Schneider Bernd
Publication year - 2012
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201200547
Subject(s) - phloem , parenchyma , picea abies , bark (sound) , botany , biology , cell wall , sieve tube element , chemistry , biochemistry , ecology
Abstract Norway spruce ( Picea abies ) bark contains specialized phloem parenchyma cells that swell and change their contents upon attack by the bark beetle Ips typographus and its microbial associate, the blue stain fungus Ceratocystis polonica . These cells exhibit bright autofluorescence after treatment with standard aldehyde fixatives, and so have been postulated to contain phenolic compounds. Laser microdissection of spruce bark sections combined with cryogenic NMR spectroscopy demonstrated significantly higher concentrations of the stilbene glucoside astringin in phloem parenchyma cells than in adjacent sieve cells. After infection by C. polonica , the flavonoid (+)‐catechin also appeared in phloem parenchyma cells and there was a decrease in astringin content compared to cells from uninfected trees. Analysis of whole‐bark extracts confirmed the results obtained from the cell extracts and revealed a significant increase in dimeric stilbene glucosides, both astringin and isorhapontin derivatives (piceasides A to H), in fungus‐infected versus uninfected bark that might explain the reduction in stilbene monomers. Phloem parenchyma cells thus appear to be a principal site of phenolic accumulation in spruce bark.