Germination test for 14 plants under different temperature and water potential conditions on the Qinghai–Tibet Plateau

With the continuous warming of the global climate, the ecological environment of the Qinghai–Tibet Plateau is highly fragile. Studying the effects of temperature and water conditions on the germination activities of wild herbage species in this region and selecting suitable grass species for ecological restoration based on these conditions is vital for stabilizing and restoring ecological barrier function. The PEG-6000 osmotic potential was used to simulate soil drought conditions, and the spring and summer temperature conditions were simulated at 10 ℃ and 20 ℃, respectively. The germination behavior of 14 native herbs on the Tibetan Plateau was studied under different temperature and water potentials. The results showed that the germination strategies of the plants tested were diversified. Most of the plants under different temperature and water potential showed that the germination rate increased or decreased along with the germination time and germination rate. 50% of the plants, comprising seven species, had significant germination time and weak responses in terms of their germination rate at the 0.05 level. 28.6% of the plants, comprising four species, showed considerable variation in the three. The germination rate index and germination time of Anaphalis xylorhiza were significantly different in individual plants. Astragalus strictus showed a weak response and Silene moorcroftiana had an increased germination rate index. Overall, the germination rate and germination rate of plant seeds increased significantly at 20 ℃, and increased with increasing water potential. The effect of temperature on germination rate was more significant than that of water potential. The germination time of 12 plant seeds at 20 ℃ was significantly shortened by 8～10 d. The plants of different families had different responses to the change in water and heat, and the plants from Compositae and Dianthus had a higher germination rate. Most of the plants could be used as established grasses for ecological restoration on the Qinghai-Tibet Plateau in summer when the moisture conditions are more suitable. Tibetan Artemisia wellbyi can also be established in summer, and S. moorcroftiana, Leontopodium nanum, and A. xylorhiza can be used as established grasses in spring.