aInstitut
de recherche en biologie végétale, Jardin botanique de Montréal,
Université de Montréal, 4101 Sherbrooke Est, Montréal, QC H1X 2B2,
Canada.
bCentre for
Research in Biotechnology and Biopharmaceuticals, Department of Biology,
University of Ottawa, Ottawa, ON K1N 6N5, Canada.
Published on the web 25 August 2014.
Received December 5, 2013. Accepted August 7, 2014.
Botany, 2014, 92(11): 783-794, 10.1139/cjb-2013-0308
Abstract
The
impact of several environmental factors on the production of phenolic
compounds in a North American medicinal plant, Labrador tea (Rhododendron groenlandicum
(Oeder) Kron & Judd), was studied. Leaves were harvested in 2006
and 2010 over a latitudinal gradient in northern Quebec, and known
phenolic markers were quantified by HPLC-DAD. The concentration of
selected compounds varied geographically where they were higher between
the 51st and 53rd parallel of northern Quebec and lower in the
peripheral northern and southern region. Major variations were observed
in the following marker compounds: (+)-catechin, (–)-epicatechin,
quercetin-3-galactoside, and an undetermined quercetin-glycoside. The
variation in phenolic compounds was best explained by short-term changes
in annual temperature range and long-term estimates of insolation
parameters such as solar radiation and photoperiod in the month of June.
