TITLE:
Leaf morphological variation among paper birch (Betula papyrifera Marsh.) genotypes across Canada
AUTHORS:
Anjala Pyakurel, Jian R. Wang
KEYWORDS:
Morphological Variation; Leaf Size; Leaf Shape; Petiole Size; Leaf Hairiness; Climatic Variables; Paper Birch
JOURNAL NAME:
Open Journal of Ecology,
Vol.3 No.4,
July
23,
2013
ABSTRACT: Variations in leaf morphological characteristics have
been extensively studied at both interand intraspecific levels although not explicitly
on paper birch (Betula papyrifera Marsh).
Paper birch populations might have considerable genotypic and leaf morphological
variations that have allowed them to inhabit wide environmental gradients. In this
study, we analyzed variations in leaf morphological characteristics in 23 paper
birch populations collected across Canada and grown in a greenhouse. Furthermore,
we examined whether the variations in leaf morphological
characteristics observed were related to the climate of the population’s
origin. We found significant genotypic differences in all leaf morphological characteristics
(p five principal components (PC) explaining 84.74% of the total variance
in the original data. PCs accumulated with specific leaf area, petiole and leaf
width were positively related to latitudinal, longitudinal, and elevational gradients
at the population’s origin. Unpredictably, these PCs were significantly negatively
correlated to precipitation and aridity index at the origin. Thus, we analyzed if
correlations within leaf morphological characteristics had supported the birch populations
to acclimate and produce unpredictable relations with the environment of origin.
Our results showed that the populations originated in limited precipitation (during
growing season) had large leaf width and
petiole size but low leaf hairs on adaxial surface. Thus, all these leaf morphological
features provide a basis for the birch to reduce water loss from leaves and balance
water use efficiency in reduced precipitation. Furthermore, the leaf characteristics
measured may also include phenotypic plasticity of the birch as an acclimation to the environment as in the greenhouse.