Environmental adaptability of the genus Carex-A case study of Carex
heterostachya and Carex breviculmis in northwest China
Abstract
Carex heterostachya (CH) and Carex breviculmis (CB) are easy to develop
lawns in a short period and exhibit high ornamental value in northwest
China. So, what type of plant functional traits has they formed for
long-term survival and adaptation to this environment, which plant is
more adaptable, as well as which leaf functional traits are critical to
photosynthetic characteristics. The result of this study suggests that
(1) CB is a slow investment-return plant with strong environmental
adaptability and plasticity in long-term shaded environments. It is
characterized by its weak photosynthetic capacity, smaller specific leaf
area, low CO2 compensation point, high water utilization rate, high
maximum carboxylation rate, as well as dark breathing rate. Moreover, it
also has a thick cuticle, and epidermal cells make CB resistant to
drought and barrenness. (2) CH is a quick investment-return plant, which
is characterized by its higher photosynthetic rate, transpiration rate,
stomatal conductance, as well as larger specific leaf area. With the
increase of the temperature and photosynthetically active radiation, CH
maintains high photosynthetic capacity by decreasing the transpiration
rate and increasing the utilization rate of light energy. Its conducting
tissue is well developed. CH have lower light saturation points and
light compensation points, and CH was more shade-tolerant than CB. (3)
Carex have strong environmental adaptability, large variation in leaf
structure traits, as well as strong plasticity. Leaf anatomical
characters are stable, whereas there are differences in the
interspecific variability and plasticity. (4) Specific leaf area (SLA)
can serve as the main factor affecting the photosynthetic availability
of Carex, the thickness of the stratum corneum(CUT), the thickness of
the upper(UET) are secondary factors. These finding can provide a
theoretical basis for the cultivation and application of Carex and the
expansion of turfgrass germplasm resources.