Abstract: In the experiment, Caragana sinica and Sophora moorcroftiana were used as test materials, and PEG solutions of different concentrations were used to simulate water stress to study the effects of water stress on seed germination and seedling growth of Caragana sinica and Sophora moorcroftiana. The results showed that in the range of PEG concentration of 0~100 g/L, with the intensification of water stress, the germination rate, germination vigor, germination index, vigor index and the length of radicle and embryo of germinating seedlings of Caragana sinica and Sophora moorcroftiana shows an overall downward trend, and the inhibition of physiological responses of Sophora moorcroftiana under sustained water stress conditions is more prominent, indicating that water stress has a greater impact on Sophora moorcroftiana; when the stress concentration reaches 150 g/L, the two plants seeds were unable to germinate, indicating that the critical PEG water stress value for the germination of Caragana sinica and Sophora moorcroftiana seeds was less than 150 g/L. From an overall point of view, Caragana sinica has stronger drought resistance ability compared with Sophora moorcroftiana, and is more suitable for growing in arid environment.

Key words: Caragana sinica, Sophora moorcroftiana, water stress, seed germination, seedling growth