Abstract: Aims As human activities continue to intensify, the strength of environmental factors affecting global ecosystems has gradually increased, and multiple factors often change simultaneously within a single ecosystem, collectively influencing plant performance. However, with the increasing number of global change factors, the trend of changes in key functional traits of mycorrhizal plants remains poorly understood. This study aimed to investigate the combined effects of multiple global change factors on the functional traits of ectomycorrhizal and arbuscular mycorrhizal plants. Methods This study employed a pot-controlled experimental approach, using seedlings of six locally common mycorrhizal plant species as subjects to investigate the effects of varying numbers of global change factors on the functional traits of two types of mycorrhizal plants. The experiment included a control treatment (0 factors) and four treatment gradients consisting of combinations of 1, 2, 4, and 8 factors. After one year of treatment, measurements were taken of plant photosynthetic rate, as well as leaf and root trait indicators, to evaluate the impact of the number of global change factors on plant functional traits. Important findings The results showed that, with increasing numbers of global change factors, photosynthetic, aboveground, and belowground functional traits exhibit linear or nonlinear changes depending on mycorrhizal types and plant species. The linear relationship between plant functional traits and the number of global change factors may reflect additive effects of multi-factor interactions, while nonlinear relationships likely result from non-additive interactions (synergistic or antagonistic effects) among the factors. These findings highlight the complex influence of global change factors on plant functional traits, as well as the unique responses of different species to environmental pressures. The results provide valuable experimental insights into the response patterns of plant traits under increasing numbers of global change factors, offering a basis for understanding and mitigating the impacts of intensified global change.

Key words: Richness of Global Change Factors, Plant functional traits, Ecto-mycorrhizal Plants, Arbuscular Mycorrhizal plants