TITLE:
Leaf Morphological and Stomatal Variations in Paper Birch Populations along Environmental Gradients in Canada
AUTHORS:
Anjala Pyakurel, Jian R. Wang
KEYWORDS:
Leaf Area, Specific Leaf Area, Leaf Adaxial Hair Density, Aspect Ratio, Stomatal Area, Stomatal Density
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.5 No.11,
May
16,
2014
ABSTRACT: Variations in leaf morphology
and stomatal characteristics have been extensively studied at both inter- and intraspecific
levels although not explicitly in the context of paper birch (Betula papyrifera Marsh) populations. The birch populations might have developed
the leaf variations that allowed them to adapt to a wide climatic gradient. Therefore,
in this study we examined variations in the leaf morphological and stomatal characteristics
of sixteen paper birch populations collected across Canada and grown in a common
garden. We also examined the relationship between these leaf characteristics and
the climate of the population’s origin. Significant genotypic differences were found
in the leaf characteristics measured among the birch populations. Thus, we expected
that the observed leaf variations may be partly explained as natural diversity in
the birch due to differences in environment of origin. We noticed that along mean
annual precipitation and aridity gradients, hair density on leaf adaxial surface
had decreased whereas stomatal density increased significantly. Our results showed
that the populations with larger leaf area and specific leaf area had higher hair
density but low stomatal density. These leaf characteristics provided a structural
basis in reducing water loss through leaves and increasing water use efficiency.
A trade-off between stomatal area and density resulted in this study might be a
strategy of the birch to balance stomatal conductance in decreased precipitation.