Figure captions
Fig 1 . The changes of total, shoot, root biomass and their ratio with gravel content for different plant species. Error bars refer to standard deviation. Different lowercase letters indicate significant differences among different gravel soils; different capital letters indicate significant differences among all treatments (p<0.05). Fe, Festuca elata ; Ed, Elymus dahuricus ; Ms, Medicago sativa ; Fe+Ed, Festuca elata plus Elymus dahuricus ; Fe+Ms, Festuca elata plus Medicago sativa ; Ms+Ed, Medicago sativa plus Elymus dahuricus ;Fe+Ms+Ed,Festuca elata plus Medicago sativa plus Elymus dahuricus .
Fig. 2 The changes of plant height and coverage with gravel content for different plant species. (a), Total coverage; (b), Plant height; (c), Coverage of different plant species; (d), Height of different plant species. Error bars refer to standard deviation. Different lowercase letters indicate significant differences among different gravel soils (p<0.05). Fe, Festuca elata ; Ed,Elymus dahuricus ; Ms, Medicago sativa ; Fe+Ed,Festuca elata plus Elymus dahuricus ; Fe+Ms, Festuca elata plus Medicago sativa ; Ms+Ed, Medicago sativa plus Elymus dahuricus ;Fe+Ms+Ed, Festuca elata plus Medicago sativa plus Elymus dahuricus .
Fig. 3 Content and stoichiometric characteristics of organic carbon, total nitrogen, and total phosphorus in plant root and shoot fractions and rhizosphere soils with different gravel contents. Error bars refer to standard deviation Different lowercase letters indicate significant differences among different gravel soils (p<0.05).
Fig. 4. Content and stoichiometric characteristics of organic carbon, total nitrogen, and total phosphorus in plant root and aboveground fractions and rhizosphere soils for different plant species. Error bars refer to standard deviation; respectively. Different lowercase letters indicate significant differences among different plant species (p<0.05). Fe, Festuca elata ; Ed, Elymus dahuricus ; Ms, Medicago sativa ; Fe+Ed, Festuca elata plus Elymus dahuricus ; Fe+Ms, Festuca elata plus Medicago sativa ; Ms+Ed, Medicago sativa plus Elymus dahuricus ;Fe+Ms+Ed,Festuca elata plus Medicago sativa plus Elymus dahuricus .
Fig. 5 RDA of the relationships among plant traits, soil properties, and their stoichiometric characteristics for different plant species. TN, soil total nitrogen; TP, soil total phosphorus; SOC, soil organic carbon;S-C/N, soil C/N ratio; S-C/P, soil C/P ratio; S-N/P, soil N/P ratio; PH, soil pH; BD, bulk density; e , total porosity; PTN, plant total nitrogen; PTP, plant total phosphorus; POC, plant organic carbon; P-C/N, plant C/N ratio; P-C/P, plant C/P ratio; P-N/P, plant N/P ratio; RTN, root total nitrogen; RTP, root total phosphorus; ROC, root organic carbon; R-C/N, root C/N ratio; R-C/P, root C/P ratio; R-N/P, root N/P ratio; H, Plant height; Tc, total coverage; Ab, aboveground biomass; Rb, root biomass; B, total biomass.
Fig 1 . The changes of total, shoot, root biomass and their ratio with gravel content for different plant species. Error bars refer to standard deviation. Different lowercase letters indicate significant differences among different gravel soils; different capital letters indicate significant differences among all treatments (p<0.05). Fe, Festuca elata ; Ed, Elymus dahuricus ; Ms, Medicago sativa ; Fe+Ed, Festuca elata plus Elymus dahuricus ; Fe+Ms, Festuca elata plus Medicago sativa ; Ms+Ed, Medicago sativa plus Elymus dahuricus ;Fe+Ms+Ed,Festuca elata plus Medicago sativa plus Elymus dahuricus .