2.1 Experimental materials
Stipa krylovii Roshev. is a Gramineae C3bunchgrass, widely distributed in the Inner Mongolia Steppe, including
the meadow grasslands – typical grasslands transition in the east, most
areas of typical grasslands in the center and some areas of desert
grasslands in the west (Liu, 2004). Significant genetic differentiation
of S. krylovii is found among regions or habitats by DNA-based
markers (Wang et al., 2006b), and both local adaptation and phenotypic
plasticity (environmental modification) play important roles in
affecting individual responses to environmental changes (Liu et al.,
2023).
In S. krylovii main distribution areas, seeds of S.
krylovii were collected within 9 populations from three regions (the
eastern, middle and western regions), and the climatic characteristics
of collection sites are shown in Table 1. Among them, the aridity index
was calculated by the ratio of regional precipitation to potential
evapotranspiration. The collected seeds were dried in the laboratory and
stored in envelope bags at -4 ℃. In the spring of 2022, seeds were
germinated and six-month seedlings were used for the following
experiment.