AMF diversity provides stable benefits for plant growth
Although the positive effects of high AMF diversity on
multifunctionality are no longer significant under multiple GCFs, its
contribution to plant aboveground biomass has become more pronounced.
Several studies suggest that the benefits of AMF diversity become more
pronounced when host plants are subjected to multiple stressors (Crossay
et al., 2019; Gosling et al., 2016; Tang et al., 2023). This aligns with
our findings regarding aboveground biomass, where under single GCF
conditions, plants in the high AMF diversity treatment exhibited 8.36%
greater aboveground biomass than those in the low diversity treatment.
Remarkably, this difference increased to 31.60% under multiple GCFs
condition (Figure 3b). The differential performance may be related to
the selection preferences of host plants in varying environmental
contexts. AMF selection is influenced by both the environment and the
host plant itself. Under single GCF conditions, plants tend to favor
specific AMF taxa that are better equipped to mitigate environmental
stress and enhance carbon resources acquisition (Tang et al., 2023;
Vályi et al., 2016). Although multiple GCFs intensified competition
among AMF, they also strengthened the host plants’ selection for AMF
species, allowing high AMF diversity still exert a positive effect on
plant performance under multiple GCFs.
High AMF diversity consistently enhanced plant net photosynthetic rate
and aboveground biomass under all GCF scenarios, exceeding both the
average effect of individual AMF inoculations and, in most cases, the
effect of the single most effective AMF (Figure 3). This illustrates the
complementarity among AMF species when inoculated as a mixture. These
findings contrast with previous meta-analysis indicating that
multi-species AMF inoculation does not significantly enhance plant
performance compared to single-species inoculation under single GCF
(Tang et al., 2023). However, it has been shown that multi-family AMF
assemblages can boost plant performance indicating that it is not the
number of AMF species that enhances plant performance, but rather the
phylogenetic diversity within the AMF community (Gosling et al., 2016;
Tang et al., 2023). Thus, the functional complementarity among different
AMF families could become increasingly crucial when multiple GCFs occur
simultaneously (Gosling et al., 2016; Horsch et al., 2023; Tang et al.,
2023).