Physiological adaptability of three gramineae plants under various vegetation restoration models in mining area of Qinghai-Tibet Plateau

Abstract

Large-scale coal mining activities on the QTP have affected the natural grassland ecosystem which will take decades to recover. Therefore, looking for an effective vegetation restoration method is the most effective way to restore the ecosystem. In this study, we explored the effects of three vegetation restoration modes (coal mine spoils planting (CK), organic fertilizer planting (OF), and cover soil planting (CS)) on the five cold-resistance related physiological indices of three native Gramineae plants (Elymus nutans, Poa crymophila and Festuca sinensis) growing in three different habitats (shady slope, sunny slope, and flat slope). The higher contents of soluble sugar (SS) in the Elymus nutans (213.46 mg/g) and Festuca sinensis (202.84 mg/g) were recorded under the CS treatment in the sunny slope habitat. The FP contents of Elymus nutans (421.31 μg/g), Poa crymophila (310.06 μg/g), and Festuca sinens (288.45 μg/g) were higher under the CK treatment in the flat ground habitat. The higher (P < 0.05) content of chlorophyll (Chl) was recorded in the Elymus nutans (2.13 mg/g) under the CS treatment in the sunny slope habitat compared to the other two plants. We observed lower MDA contents in the Elymus nutans (3.19 nmol/g) and Festuca sinensis (3.56 nmol/g) under the CK treatment growing in the shady slope habitat. In the shady slope habitat, the H2O2 contents of Elymus nutans (15.86 μmol/g), Poa crymophila (6.78 μmol/g), and Festuca sinensis (8.76 μmol/g) under the CS treatment were significantly lower compared to other treatments. Based on membership function method, the low-temperature adaptability order of the three restoration plants from strong to weak was Elymus nutans > Festuca sinensis > Poa crymophila. While the effectiveness order of the three vegetation restoration models in alpine mining areas from good to bad was CS > OF > CK. This study will provide a theoretical and guiding significance to evaluate the effectiveness of different restoration methods, formulate optimal restoration strategies and guide the sustainable restoration of the damaged ecosystems of the alpine mining areas.