ASSESSING THE ROLE OF MYCORRHIZAL FUNGI IN ENHANCING DROUGHT TOLERANCE IN NATIVE PLANTS: IMPLICATIONS FOR ECOLOGICAL RESTORATION

Abstract

Drought stress poses a significant challenge to the establishment and persistence of native plant communities in degraded, semi‐arid landscapes. In this study, we evaluated the role of arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF) in enhancing drought tolerance of three ecologically important native species under field conditions. Randomized plots were inoculated with AMF, EMF, or left uninoculated (control) and subjected to well‐watered (80% field capacity) or drought (30% field capacity) regimes for eight weeks. We monitored above‐ground biomass, leaf water potential, stomatal conductance, chlorophyll fluorescence, and soil moisture dynamics, and quantified root colonization via staining and qPCR. AMF‐inoculated plants maintained 25 g biomass under well‐watered and 15 g under drought conditions—significantly higher than EMF (23 g; 14 g) and controls (20 g; 10 g). AMF treatments also exhibited less negative water potentials (–0.40 MPa vs. –0.80 MPa under drought), higher stomatal conductance (160 vs. 120 mmol m⁻² s⁻¹), and improved photosystem II efficiency (Fv/Fm = 0.82 vs. 0.75) compared to controls. Soil moisture in AMF‐drought plots averaged 30.5%, exceeding both control (28.3%) and EMF (29.0%) plots. Root colonization surpassed 70% for AMF and ~60% for EMF, confirming symbiont establishment. Moreover, AMF treatments achieved the highest water‐use efficiency (0.50 g biomass per % water), underscoring their capacity to optimize resource use under water limitation. These findings demonstrate that targeted mycorrhizal inoculation—especially with AMF—can significantly improve plant performance, water relations, and biomass production in drought‐prone restoration sites. Incorporating such biotic amendments into restoration protocols offers a practical strategy to bolster ecosystem resilience amid escalating climate stress.