Environmental adaptability of the genus Carex-A case study of Carex heterostachya and Carex breviculmis in northwest China

Carex heterostachya (CH) and Carex breviculmis (CB) are easy to develop lawns in a short period and exhibit high ornamental value in northwest China with high summer temperatures, uneven rainfall, and poor soil. Several questions are raised, including 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. After exploring the leaf functional traits of the two plants by gas exchange technology and field emission electron scanning technology, the following conclusions are drawn: (a) CB is a slow investment-return plant, which exhibits strong environmental adaptability and plasticity, and is resistant to barrenness, drought and shade. CH is a kind of quick investment-return plant, with high photosynthetic efficiency, well-developed transport tissue, and relatively shade-tolerant. The soil with low water content and poorer soil is suitable for CB cultivation, and CH is suitable for cultivation in the environment with sufficient light and rich nutrients. At the same time, both CB and CH can be used to enrich the diversity of understory landscape. (b) 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. (c) 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.