The experimental growth microcosmic device.

The experimental device consists of three compartments, two planting compartments (one for the native E. adenophorum and one for the invasive A. annua) on opposite sides flanking one competition compartment in the center. The size of each of the three compartments was about 10 cm × 10 cm × 10 cm (length × width × height). Five circular holes were drilled on a baffle plate separating the planting compartments and the competition compartment. 20μm or 0.45μm nylon meshes were attached to both sides of the baffle plate to form an air gap to prevent the flow of nutrients among compartments. The 20μm nylon mesh allows mycelium to pass through, but the plant roots cannot; the 0.45μm nylon mesh does not allow either mycelium nor plant roots to pass through. More detailed description in the text. Pc = planting compartment; Cc = competition compartment.