Carbon Cost of the Fungal Symbiont Relative to Net Leaf P Accumulation in a Split-Root VA Mycorrhizal Symbiosis.

摘要: Translocation of 14C-photosynthates to mycorrhizal (+ +), half (0+), and nonmycorrhizal (00) split-root systems was compared P accumulation in leaves the host plant. Carrizo citrange seedlings (Poncirus trifoliata [L.] Raf. × Citrus sinensis Osbeck) were inoculated with vesicular-arbuscular fungus Glomus intraradices Schenck Smith. Plants exposed 14 CO2 for 10 minutes ambient air 2 hours. Three 4% recently labeled photosynthate allocated metabolism mycorrhiza each root independent shoot concentration, growth response, whether one or both halves colonized. Nonmycorrhizal roots respired more label translocated them than did roots. Label recovered potting medium due exudation transport into extraradical hyphae 5 6 times greater +) versus plants. In low nutrient media, (0+) plants transported per weight However, when C utilized respiration, exudation, etc., as well is considered, plant at least efficient uptake (benefit) (cost) Root not supply higher yet they still twice 14C-photosynthate systems. This indicates there an optimal level colonization above which receives no enhanced continues partition photosynthates mycorrhiza.