FIGURE LEGENDS
FIGURE 1 The location of the central and edge populations of G. quadriradiata in China.
FIGURE 2 The total mass of the central and edge populations ofG. quadriradiata under different treatments. The invasive plant population types are edge (Edge) and central populations (Central). Three levels of nitrogen treatments are deionized water (Ambient N), 3 g L-1 NH4NO3 solution (Low N), and 6 g L-1NH4NO3 solution (High N). Culture and competitor types: single-culture with no competitor (None), mixed with new competitors (New competitor), and mixed with old competitors (Old competitor). Different letters indicate significant differences atp < 0.05 in each subgraph. Values are means ± SE.
FIGURE 3 Comparison of the relative competition index (RCI) of the central and edge populations of G. quadriradiata under nitrogen treatments and different competitor types. The invasive plant population types: edge population (Edge) and central population (Central). Three levels of nitrogen treatments: deionized water (Ambient N), 3 g L-1 NH4NO3solution (Low N), and 6 g L-1NH4NO3 solution (High N). Competitor types: mixed with new competitors (New competitor), and mixed with old competitors (Old competitor). Different letters indicate significant differences at p < 0.05. Values are means ± SE.
FIGURE 4 Comparison of the number of capitula per plant (NCP) of the central and edge populations of G. quadriradiata under nitrogen treatments, different culture, and different competitor types (nested in Culture). The invasive plant population types: edge population (Edge) and central population (Central). Three levels of nitrogen treatments: deionized water (Ambient N), 3 g L-1 NH4NO3 solution (Low N), and 6 g L-1NH4NO3 solution (High N). Culture and competitor types: single-culture with no competitor (None), mixed with new competitors (New competitor), and mixed with old competitors (Old competitor). Different letters indicate significant differences atp < 0.05 in each subgraph. Values are means ± SE.
FIGURE 5 Comparison of the root mass ratio (RMR) of the central and edge populations of G. quadriradiata under nitrogen treatments, different culture, and different competitor types (nested in Culture). The invasive plant population types: edge population (Edge) and central population (Central). Three levels of nitrogen treatments: deionized water (Ambient N), 3 g L-1NH4NO3 solution (Low N), and 6 g L-1 NH4NO3 solution (High N). Culture and competitor types: single-culture with no competitor (None), mixed with new competitors (New competitor), and mixed with old competitors (Old competitor). Different letters indicate significant differences at p < 0.05. Values are means ± SE.
FIGURE 6 Comparison of the leaf nitrogen concentration (LNC) and leaf phosphorus concentration (LPC) of G. quadriradiata under different treatments. Three levels of nitrogen treatments (NTC): treated with deionized water (Ambient N), 3 g L-1NH4NO3 solution (Low N), or 6 g L-1 NH4NO3 solution (High N). The invasive plant population types: edge population and central population. Competitor types: single-culture with no competitor (None), mixed with new competitors (New competitor), and mixed with old competitors (Old competitor). In the bars of figure a and c, the data of no competitors and different competitors summed together. In the bars of figure b and d, the data of different nitrogen treatments summed together. Different letters indicate significant differences at p< 0.05 in each subgraph. Values are means ± SE.
FIGURE 7 Comparison of the CCmass of the central and edge populations of G. quadriradiata under nitrogen treatments and different competitor types. The invasive plant population types: edge population (Edge) and central population (Central). Three levels of nitrogen treatments: deionized water (Ambient N), 3 g L-1 NH4NO3 solution (Low N), and 6 g L-1NH4NO3 solution (High N). Competitor types: mixed with new competitors (New competitor), and mixed with old competitors (Old competitor). Different letters indicate significant differences at p < 0.05. Values are means ± SE.