This study investigated the temperature adaptability of three grass species （Elymus nutans， Bromus inermis， and Festuca sinensis） through the controlled experiments simulating diurnal thermal regimes （10℃/5℃， 15℃/5℃， 20℃/5℃， 25℃/10℃） characteristic of their natural habitat during March-November. We systematically analyzed seed germination dynamics （quantified by germination rate， potential， and index）， seedling growth parameters， and physiological stress markers to elucidate species-adaptive responses to temperature gradients in Alpine region. With the increase of temperature， the germination rate， germination potential and germination index of the Elymu snutans seeds all increased first and then decreased. The germination rate， germination potential and germination index of Bromus inermis and Festuca sinensis seeds increased significantly with the increase of temperature. The contents of malondialdehyde （MDA）， soluble sugar （SS） and free proline （Pro） of the three grass seedlings increased with decreasing temperature. The results showed that the optimum temperature was 20℃/5℃ for Elymus nutans， 25℃/10℃ for Bromus inermis and Festuca sinensis. The comprehensive evaluation of the membership function showed that the temperature adaptability of the three grass species was Elymu snutans > Bromus inermis > Festuca sinensis.

Temperature change  /  Elymus nutans  /  Bromus inermis  /  Festucas inensis  /  Seed germination  /  Physiological characteristics