Tracking carbon from the atmosphere to the rhizosphere

Abstract

AbstractTurnover rates of arbuscular mycorrhizal (AM) fungi may influence storage of soil organic carbon (SOC). We examined the longevity of AM hyphae in monoxenic cultures; and we also used 13C incorporation into signature fatty acids to study C dynamics in a mycorrhizal symbiosis involving Glomus intraradices and Plantago lanceolata. 13C enrichment of signature fatty acids showed rapid transfer of plant assimilates to AM fungi and a gradual release of C from roots to rhizosphere bacteria, but at a much slower rate. Furthermore, most C assimilated by AM fungi remained 32 days after labelling. These findings indicate that 13C labelled fatty acids can be used to track C flux from the atmosphere to the rhizosphere and that retention of C in AM fungal mycelium may contribute significantly to SOC.