Arbuscular mycorrhizal fungi improve the competitive advantage of a native plant relative to a congeneric invasive plant in growth and nutrition

Abstract

Plant invasions severely threaten natural ecosystems, and invasive plants often outcompete native plants across various ecosystems. Arbuscular mycorrhizal (AM) fungi, serving as beneficial microorganisms for host plants, can greatly influence the competitive outcomes of invasive plants against native plants. However, it remains unclear how AM fungi alter the competitive balance between native and invasive species. A competitive experiment was conducted using an invasive Eupatorium adenophorum paired with a native congener Eupatorium lindleyanum. Specifically, both species were inoculated with (M⁺) or without (M^-) the fungus Glomus etunicatum under intraspecific (Intra-) and interspecific (Inter-) competition. Plant traits were measured and analyzed regarding the growth and nutrition of both species. The results exhibited that the AM fungus significantly increased the height, diameter, biomass, C, N, and P acquisition of both the invasive E. adenophorum and the native E. lindleyanum. The root mycorrhizal colonization and the mycorrhizal dependency of native E. lindleyanum were greater than those of invasive E. adenophorum. Under M⁺, the Inter-competition inhibited the growth and nutrition of invasive E. adenophorum compared to the Intra- competition. Further, native E. lindleyanum exhibited higher competitiveness than invasive E. adenophorum in growth and nutrition. Meanwhile, the AM fungus significantly improved the competitiveness of native E. lindleyanum over invasive E. adenophorum. In conclusion, AM fungus improved the competitive advantage of native E. lindleyanum over invasive E. adenophorum in growth and nutrition, potentially contributing to native species competitively resisting the invasion of exotic species. These findings emphasize the importance of AM fungi in helping native plants resist the invasion of exotic plants and further contribute to understanding plant invasion prevention mechanisms.

Keywords: arbuscular mycorrhizal fungi; competition; nutrition acquisition; plant growth; plant invasion.

FIGURE 1

Schematic diagram of the experimental design. Two plant species (invasive plant Eupatorium adenophorum and native plant Eupatorium lindleyanum) were grown in intraspecific (Intra‐) competition or interspecific (Inter‐) competition, and with (M⁺) or without (M⁻) inoculation of AM fungus Glomus etunicatum in autoclaved soil.

FIGURE 2

The height, diameter, biomass, and R/S ratio of invasive plant Eupatorium adenophorum and native plant Eupatorium lindleyanum. Intra‐, intraspecific competition; Inter‐, interspecific competition; M⁺, with AM fungus; M⁻, without AM fungus. The * indicates a significant difference (p < .05), the ** and *** (p < .01 and p < .001) indicate an extremely significant difference, and the ns (p > .05) indicates a non‐significant difference between M⁺ and M⁻ or Intra‐ and Inter‐; the different Greek letters (α, β) indicate significant differences between invasive E. adenophorum and native E. lindleyanum (p < .05) under M⁺ and M⁻ treatments or Intra‐ and Inter‐ conditions. The error bars represent standard error.

FIGURE 3

The C, N, and P acquisition of invasive plant Eupatorium adenophorum and native plant Eupatorium lindleyanum. M⁺ and M⁻; Intra‐ and Inter‐, implications are the same as in Figure 2; the *, **, *** and ns, and the Greek letters α and β above the bars, implications are the same as in Figure 2.

FIGURE 4

The competition intensity and competitive ability of invasive plant Eupatorium adenophorum and native plant Eupatorium lindleyanum. M⁺ and M⁻ implications are the same as in Figure 2; CB, competitive balance index; RY, relative yield. The *, **, ***, and ns implications are the same as in Figure 2.

FIGURE 5

The principal component analysis (PCA) for soil physicochemical properties and plant traits. The PCA involves the relationships between the soil physicochemical properties (soil pH, SOC, TN, AN, TP, AP) and plant traits (root mycorrhizal colonization: %AMF, height, diameter, biomass, C, N and P acquisition) of invasive Eupatorium adenophorum and native Eupatorium lindleyanum.

FIGURE 6

The correlation between plant traits and soil physicochemical properties. AN, alkaline nitrogen; AP, alkaline phosphorus; SOC, soil organic carbon; TN, total nitrogen; TP, total phosphorus.