Comprehensive evaluation of cold resistance of four Elymus forage varieties at the seedling stage

To comprehensively compare the cold resistance of four forage grass species of Elymus, we used four Elymus forages (E. breviaristatus ‘Tongde’, E. sibiricus ‘Tongde’, E. excelsus ‘Longzhong No. 1’ and E. nutans ‘Gannan’) as experimental materials. We determined their antioxidant enzyme activity, osmoregulatory substance content, photosynthetic gas exchange parameters, and chlorophyll fluorescence parameters under four forage grass species under different treatments at four temperature gradients of 25, 10, 5, and 0 ℃. The cold resistance of these four forage grass species was evaluated comprehensively using the weighting method of the affiliation function. The results showed that under the four temperature gradients, the following parameters differed significantly (P < 0.05): T_r and G_s of E. breviaristatus ‘Tongde’, P_n, C_i, and ETR values of E. sibiricus ‘Tongde’, qP, Φ_PSⅡ, and free proline accumulation of E. nutans ‘Gannan’, and SS accumulation and REC of E. excelsus ‘Longzhong No. 1’. The combined test results indicate that the comprehensive cold resistance ranking of the four Elymus forages is as follows: E. sibiricus ‘Tongde’ > E. breviaristatus ‘Tongde’ > E. nutans ‘Gannan’ > E. excelsus ‘Longzhong No. 1’. This study provides a reference for planting alpine artificial grassland and for ecological restoration using Elymus.