Abstract
Drought can reduce productivity and resource availability below ground, with lasting effects on biogeochemical function. We hypothesize that mycorrhizal fungi support resilience to drought by facilitating microbial access to recent photosynthate carbon (C). We employed 13CO2 labeling chambers and stable isotope probing to investigate how the common arbuscular mycorrhizal fungus Rhizophagus irregularis influences C dynamics in soils planted with the bioenergy grass model Panicum hallii. After eight weeks, water limitation resulted in an increase in both the total quantity of recent photosynthate C that accrued in the rhizosphere and in the quantity of photosynthate C assimilated by rhizosphere bacteria. Despite robust mycorrhizal colonization of inoculated roots, mycorrhizal effects on net C accrual were small compared to the effects of water limitation. However, distinct microbial communities assimilated photosynthate C in mycorrhizal-inoculated soil and exhibited greater growth potential and efficiency once moisture levels were restored in drought-affected soil. Together, these findings elucidate how mycorrhizal symbioses mediate ecosystem resilience to drought.
Publication Date
10-1-2025
Document Type
Presentation
Recommended Citation
Hestrin, Rachel, "Fall 2025 Environmental Sciences Seminar Series, Rachel Hestrin" (2025). NRESS Seminars. 3.
https://scholars.unh.edu/nress_seminars/3