Carbon cost of the fungal symbiont relative to net leaf P accumulation in a split-root VA mycorrhizal symbiosis. [Poncirus trifoliata L. Raf. x Citrus sinensis L. Osbeck; Glomus intraradices Schenk and Smith]

Journal Article · Mon Feb 01 00:00:00 EST 1988 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.86.2.491· OSTI ID:7194625

Douds, Jr, D D; Johnson, C R; Koch, K E ^[1]

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1. Univ. of Florida, Gainesville (USA)

Translocation of {sup 14}C-photosynthates to mycorrhizal (++), half mycorrhizal (0+), and nonmycorrhizal (00) split-root systems was compared to P accumulation in leaves of the host plant. Carrizo citrange seedlings (Poncirus trifoliata (L.) Raf. {times} Citrus sinensis (L.) Osbeck) were inoculated with the vesicular-arbuscular mycorrhizal fungus Glomus intraradices Schenck and Smith. Plants were exposed to {sup 14}CO{sub 2} for 10 minutes and ambient air for 2 hours. Three to 4% of recently labeled photosynthate was allocated to metabolism of the mycorrhiza in each inoculated root half independent of shoot P concentration, growth response, and whether one or both root halves were colonized. Nonmycorrhizal roots respired more of the label translocated to them than did mycorrhizal roots. Label recovered in the potting medium due to exudation or transport into extraradical hyphae was 5 to 6 times greater for (++) versus (00) plants. In low nutrient media, roots of (0+) and (++) plants transported more P to leaves per root weight than roots of (00) plants. However, when C translocated to roots utilized for respiration, exudation, etc., as well as growth is considered, (00) plant roots were at least as efficient at P uptake (benefit) per C utilized (cost) as (0+) and (++) plants. Root systems of (++) plants did not supply more P to leaves than (0+) plants in higher nutrient media, yet they still allocated twice the {sup 14}C-photosynthate to the mycorrhiza as did (0+) root systems.

• OSTI ID: 7194625
• Journal Information: Plant Physiology; (USA), Vol. 86:2; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PHYSIOLOGY
CARBON 14 COMPOUNDS
CARBON DIOXIDE
FUNGI
LEAVES
METABOLISM
PHOSPHORUS
PLANT GROWTH
RESPIRATION
ROOTS
SYMBIOSIS
TRACER TECHNIQUES
TRANSLOCATION
UPTAKE
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
ELEMENTS
GROWTH
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PLANTS
551001* - Physiological Systems- Tracer Techniques