Effects of Co2 and O3 on the interaction between root of woody plants and ectomycorrhizae

Abstract

The increase of atmospheric carbon dioxide (CO2) and tropospheric ozone (O3) concentrations has affected forest ecosystems both above and below ground. A high dose of O3 alters stomatal function and accelerates foliar senescence, which lead to changes in assimilation and water use efficiency. Consequently, biomass production and plant growth are suppressed by elevated levels of O3. In contrast, elevated CO2 ameliorates these responses of plants to high O3 via stomatal closure. The harmful effect of O3 on above ground is indirectly linked with below-ground. Importantly, the fine root dynamics and the relationship with symbiotic fungi are significantly influenced. However, the effects of such a changing environment on forest rhizosphere are still poorly understood. The aim of this study is to analyze the combination effect of CO2 and O3 on tree roots and ectomycorrhizae. In particular, we summarize and discuss 1) the response of ectomycorrhizal symbionts (colonization rate, community composition, richness, and diversity) under these environmental stresses; and 2) the root dynamics under elevated CO2 and O3 concentrations, along with current methodologies used for root sampling.