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New Phytol

Title:		Carbohydrate translocation determines the phenolic content of Populus foliage: a test of the sink-source model of plant defense
Author(s):		Arnold T; Appel H; Patel V; Stocum E; Kavalier A; Schultz J;
Address:		"Department of Biology, Dickinson College, Carlisle, PA 17013, USA. Pesticide Research Laboratory, Department of Entomology, Penn State University, State College PA 19958, USA. Department of Biology, College of Charleston, Charleston SC 29404, USA"
Journal Title:		New Phytol
Year:		2004
Volume:		164
Issue:		1
Page Number:		157 - 164
DOI:		10.1111/j.1469-8137.2004.01157.x
ISSN/ISBN:		1469-8137 (Electronic) 0028-646X (Linking)
Abstract:		"* Here, we examine the influence of source-to-sink carbohydrate (CHO) flow on the development of constitutive and inducible levels of phenylpropenoids in hybrid poplar (Populus nigra x P. deltoides) foliage to determine if secondary metabolic processes in plant modules can be inhibited in a predictable manner by events such as herbivory and the development of new leaves and reproductive structures, which alter the path of phloem-borne resources. * Phenylpropenoid concentrations were determined for developing foliage after CHO flow, measured as the translocation of (13) C from labeled sources was manipulated. * Phenylpropenoid metabolism in both unwounded and induced sink leaves was directly and positively linked to rates of CHO import. Alterations in rates of translocation yielded different results, depending on how CHO import was affected: the removal of competing sinks rapidly and dramatically increased leaf phenolic contents, whereas phenolic levels (and their inducibility) tended to be reduced when import was interrupted. * High and inducible sink strength in developing poplar leaves provides resources for phenolic biosynthesis and, as a result, restrictions or re-directions of CHOs affect the foliar quality. Sink strength and the vascular architecture of plants, which confer upon them a modular nature, can determine the direction and magnitude of defense responses in trees"
Keywords:		Populus condensed tannin induced defense invertase phyllotaxy polyphenol sink strength;
Notes:		"PubMed-not-MEDLINEArnold, Tom Appel, Heidi Patel, Vishal Stocum, Eileen Kavalier, Adam Schultz, Jack eng England 2004/10/01 New Phytol. 2004 Oct; 164(1):157-164. doi: 10.1111/j.1469-8137.2004.01157.x"