Parasquive, Vlad;
Brisson, Jacques;
Guilbeault-Mayers, Xavier;
Laliberté, Etienne;
Chagnon, Pierre-Luc
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2023-05-15
<p><u><span lang="EN-CA" style="background:white;">Introduction</span></u><span lang="EN-CA" style="background:white;">: Plant nutrient acquisition strategies range along a spectrum from autonomous foraging to investment in cooperative foraging through mycorrhizal associations. However, in temperate ecosystems, </span><span lang="EN-CA">many plant species encounter contrasted levels of symbiont availability in open fields versus closed forests<span style="background:white;">. Little is known about how fungal partner availability may be associated with intraspecific variation in other root foraging traits in natural settings.</span></span></p>
<p><u><span lang="EN-CA" style="background:white;">Methods</span></u><span lang="EN-CA" style="background:white;">: Here, we addressed this issue by sampling saplings from two tree species: the arbuscular mycorrhizal (AM) <em>Acer rubrum</em> and the ectomycorrhizal (ECM) <em>Quercus rubra</em> from open fields (AM-dominated) and adjacent forest plots (ECM-dominated). For each species and environment, we measured morphological, architectural, and symbiotic root traits.</span></p>
<p><u><span lang="EN-CA" style="background:white;">Results</span></u><span lang="EN-CA" style="background:white;">: For the open field, <em>Quercus</em> had greater specific root length (SRL) while <em>Acer</em> had higher AM colonization and root diameter. In the closed forest, the opposite pattern was observed, namely <em>Quercus</em> had higher ECM colonization and <em>Acer</em> greater SRL. </span></p>
<p><u><span lang="EN-CA" style="background:white;">Discussion</span></u><span lang="EN-CA" style="background:white;">: Both species showed evidence of a shift toward autonomous root foraging in the habitat with low expected symbiont abundance (open field for <em>Quercus</em> and forest for <em>Acer</em>). </span><span lang="EN-CA" style="background:white;">Although the confounding effects of site abiotic properties could not be strictly controlled in this study, these results suggest that plants might adjust root foraging traits according to local habitat conditions.</span></p>
<p><u><span lang="EN-CA" style="background:white;">Synthesis</span></u><span lang="EN-CA" style="background:white;">: Our results shed new light on the intraspecific variation in plant position along the so-called “collaboration gradient”, and suggest that mycorrhizal symbiont availability, along with other factors such as competition and site properties, may contribute to this variation.</span></p>
