Effects of temperature and water potential on seed germination of 13 Poa L. species in the Qinghai-Tibetan Plateau

Human activity, combined with climate change, has led to severe degradation of natural grasslands all over the world. As such, artificial grasslands created with species suited to the geographical area present a popular alternative. However, species that are both native and suitable for creating artificial grasslands are rare, especially in the Qinghai-Tibetan Plateau of China. In this study, we performed two experiments respectively with varied temperature and water potential, to evaluate the cold and drought resistance of 13 local Poa L. species in the Qinghai Province of China. Within the range of 0–20 °C, our results showed that increase in temperature increased the germination indices of all 13 species, with some species germinating even at 5 °C, demonstrating relatively cold-resistant species in our study. Similarly, decrease in moisture levels decreased the germination percentages of all species in this experiment, with several species germinating at even −1.2 MPa, which were considered as relatively higher drought-resistant species in this study. Among the 13 species, P. malaca, P. paucifolia, and P. sphondylodes exhibited relatively strong cold-resistance, while P. poophagorum, P. pratensis var. anceps Gaud. cv. Qinghai, and P. pratensis cv. Qinghai showed relatively high drought resistance. Overall, the results indicated that all the 13 native grass species evaluated in the study were suitable for planting and cultivation on the Qinghai-Tibetan Plateau. This study could provide insights into identifying suitable species for plant breeding in Qinghai-Tibetan plateau and establish a protocol for germplasm evaluation of local Poa L. species. Further, these findings can help evaluate and identify more native species suited for the restoration of degraded grasslands, especially under the scenario of climate change.