Associations among leaf developmental stability, canalization and
phenotypic plasticity in response to population density in Abutilon
theophrasti under contrasting soil conditions at different growth stages
Abstract
Most studies on animals have conducted comparative studies to deduce the
possible relationships among developmental stability, canalization and
phenotypic plasticity, there is a lack of direct evidence in plants,
which should be better study materials. To investigate the correlations
among developmental stability, canalization and plasticity in plants, we
conducted a field experiment with Abutilon theophrasti, by subjected
plants to three densities under infertile vs. fertile soil conditions,
and measured leaf size, leaf fluctuating asymmetry (FA), and calculated
coefficient of variation among leaves within individuals (CVleaf) and
among individuals (CVin) and relative plasticity (PIrel) and its degree
in leaf size at three growth stages, to analyze the responses of their
correlations to density and how they may vary with soil conditions or
growth stages. Results showed a decrease of FA, CVleaf and PIrel and an
increase of CVin in leaf size, with increased density. In most cases,
there were no correlations among these variables, but negative
correlations between CVin and PIrel, positive correlations between FA
and PIrel at high density and/or in fertile soil, in infertile soil. It
suggested that higher FA may indicate the state of faster growth rather
than an indicator of environmental stresses; there are correlations
among developmental stability, canalization and plasticity, which may be
complex, affected by other factors. The loss of developmental stability
may be beneficial for plant response to environmental stresses, while
decreased canalization can be either disadvantageous or advantageous,
depending on that the size variation results from an increase or
decrease of smaller individuals, and whether its correlations with other
variables reflect beneficial or adverse environmental effects.