Effects of arbuscular mycorrhizal fungi on plant growth depend on root system: a meta-analysis

Our aim was to explore the way that root system type affects mycorrhizal growth response of plants. An extensive meta-analysis with 943 peer-review publications was conducted to test the difference in mycorrhizal responses between taproot plants and plants with a fibrous root system. We found that taproot plants showed greater growth response (biomass, P and N uptake) to colonization by arbuscular mycorrhizal fungi (AMF) than do plant species with fibrous root systems. This response pattern was dependent on stress types, AMF identity and species richness, and particularly the type of stress (abiotic vs. biotic). Taproot plants respond more to AMF than plants with a fibrous root system; but no difference was shown under biotic stress. The interaction effect seen for AMF and biotic stress was significantly higher for plants with fibrous root system, but was not significant between taproot plants and abiotic stress. Difference in biomass response was only found for Glomeraceae and Gigasporaceae between the two types of plants, while difference was found in P uptake response for Glomeraceae and Claroideoglomeraceae. However, plants with fibrous root system showed higher growth response than taproot plants under nematode stress. Taproot plants might be more dependent on mycorrhiza than plants with fibrous root system. This indicates that environmental conditions can modify the relative abundance of taproot plants and plants with fibrous root system through mycorrhizal functioning, which will regulate plant community dynamics and processes.