43 research outputs found
Soil fungal networks maintain local dominance of ectomycorrhizal trees
The mechanisms regulating community composition and local dominance of trees in species-rich forests are poorly resolved, but the importance of interactions with soil microbes is increasingly acknowledged. Here, we show that tree seedlings that interact via root-associated fungal hyphae with soils beneath neighbouring adult trees grow faster and have greater survival than seedlings that are isolated from external fungal mycelia, but these effects are observed for species possessing ectomycorrhizas (ECM) and not arbuscular mycorrhizal (AM) fungi. Moreover, survival of naturally-regenerating AM seedlings over ten years is negatively related to the density of surrounding conspecific plants, while survival of ECM tree seedlings displays positive density dependence over this interval, and AM seedling roots contain greater abundance of pathogenic fungi than roots of ECM seedlings. Our findings show that neighbourhood interactions mediated by beneficial and pathogenic soil fungi regulate plant demography and community structure in hyperdiverse forests
Defoliation of interior Douglas-fir elicits carbon transfer and stress signalling to ponderosa pine neighbors through ectomycorrhizal networks
How belowground interactions contribute to the coexistence of mycorrhizal and non-mycorrhizal species in severely phosphorus-impoverished hyperdiverse ecosystems
Resilience of Rhizopogon-Douglas-fir mycorrhizal networks 25Â years after selective logging
Native and non-native trees can find compatible mycorrhizal partners in each otherâs dominated areas
The potential for phosphorus benefits through root placement in the rhizosphere of phosphorus-mobilising neighbours
Root dynamics and survival in a nutrient-poor and species-rich woodland under a drying climate
Background and aims In Australiaâs Mediterranean hyperdiverse vegetation, species that produce cluster roots to mobilise poorly-available nutrients (e.g. Banksia spp.) are an important functional and structural component. Cluster roots are only active during the wet season, indicating a strong dependence on suitable surface soil moisture conditions. Winter rainfall in this region is declining due to global climate change, with a delayed commencement of rains and a decline in precipitation. It is unknown how lower soil moisture levels will affect the root dynamics of these globally-significant plant communities. Methods We determined the root dynamics and root lifespan with minirhizotrons with or without irrigation to simulate reduced rainfall scenarios. Results We found a major effect of irrigation on the early production (0.24 m m-2 d-1 increase), occurrence (97% increase) of cluster roots and only slight effects on lifespan (~10 days less) of all root types. With irrigation, the resultant greater soil moisture levels increased the deployment of cluster roots. Apart from cluster roots, the dynamics of other roots did not decline at lower soil moisture levels, suggesting that this system shows some resilience to decreased rainfall. Conclusions Future research should focus on assessing if climate-altered cluster-root activity may be promoting compositional shifts in plant communities with additional restraining effects on root trait diversity
Calculating the uncertainty associated with log response ratios in plantâsoil feedback studies
The roles of arbuscular mycorrhizal fungi (AMF) in phytoremediation and tree-herb interactions in Pb contaminated soil
Understanding the roles of arbuscular mycorrhizal fungi (AMF) in plant interaction is essential for optimizing plant distribution to restore degraded ecosystems. This study investigated the effects of AMF and the presence of legume or grass herbs on phytoremediation with a legume tree, Robinia pseudoacacia, in Pb polluted soil. In monoculture, mycorrhizal dependency of legumes was higher than that of grass, and AMF benefited the plant biomass of legumes but had no effect on grass. Mycorrhizal colonization of plant was enhanced by legume neighbors but inhibited by grass neighbor in co-culture system. N, P, S and Mg concentrations of mycorrhizal legumes were larger than these of non-mycorrhizal legumes. Legume herbs decreased soil pH and thereby increased the Pb concentrations of plants. The neighbor effects of legumes shifted from negative to positive with increasing Pb stress levels, whereas grass provided a negative effect on the growth of legume tree. AMF enhanced the competition but equalized growth of legume-legume under unpolluted and Pb stress conditions, respectively. In conclusion, (1) AMF mediate plant interaction through directly influencing plant biomass, and/or indirectly influencing plant photosynthesis, macronutrient acquisition, (2) legume tree inoculated with AMF and co-planted with legume herbs provides an effective way for Pb phytoremediation