Effect of root exudates of Eucalyptus urophylla and Acacia mearnsii on soil microbes under simulated warming climate conditions

Abstract

Background Recent studies demonstrated that warming and elevated carbon dioxide (CO2) indirectly affect the soil microbial community structure via plant root exudates. However, there is no direct evidence for how the root exudates affect soil microbes and how the compositions of root exudates respond to climate change. Results The results showed that warming directly decreased biomass of soil-borne bacteria and fungi for Acacia mearnsii De Willd but it did not impact soil microbial community for Eucalyptus urophylla S.T. Blake. In contrast, elevated CO2 had strong direct effect on increasing soil microbial biomass for both plant species. However, plant roots could significantly increase the secretion of antibacterial chemicals (most probable organic acids), which inhibited the growth of bacteria and fungi in elevated CO2 environment. This inhibitory effect neutralized the facilitation from increasing CO2 concentration on microbial growth. Conclusions We concluded that climate change can directly affect microorganisms, and indirectly affect the soil microbial community structure by changes in composition and content of plant root exudates.

Effects of long-term nitrogen addition on soil respiration and its components in a boreal forest

“…The positive response of Rs to soil temperature change may be related to the variations of soil matrix availability and microbial abundance (Noh et al 2017;Sun et al 2019). Previous studies have shown that warming may increase FRB, root exudates or litter decomposition (Gong et al 2015;Liu et al 2017b;Wu and Yu 2019). In our study, FRB in July was signi cantly higher than that in May (Fig.…”

Tree mycorrhizal type and tree diversity shape the forest soil microbiota

“…Tree species (host) can select the soil microbiota, for instance, by the effects of tree species identity (Wubet et al ., 2009; Weißbecker et al ., 2018) and the genotype (Karliński et al ., 2020). These effects can be mediated through modulating the soil chemistry resources (Urbanová et al ., 2015; Wu and Yu, 2019). Assuming that each tree species to some extent can have species‐specific and generalist soil microbial communities, one would expect an increasing number of microbial species with increasing tree diversity covering more and more taxa of the local microbial species pool.…”

Effects of Elevated Temperature and High and Low Rainfall on the Germination and Growth of the Invasive Alien Plant Acacia mearnsii

“…The ability of A. mearnsii to adapt rapidly to future climate change implies that it can easily overcome invasion barriers and constraints caused by climate change, thus, becoming more invasive in future [ 42 ]. For example, Wu and Yu [ 45 ] showed that although soil microorganisms underneath A. mearnsii soils are sensitive to increased warming and elevated CO 2 , A. mearnsii tends to respond by increasing root exudates and root length, which subsequently increases its growth through increased nutrient uptake and photosynthetic capacity. Based on the above-mentioned study, the positive effect of increased warming and elevated CO 2 on A. mearnsii root exudates and root length can be viewed as an environmental adaptation strategy.…”