Premium
Arbuscular mycorrhizal colonization on carbon economy in perennial ryegrass: quantification by 13 CO 2 / 12 CO 2 steady‐state labelling and gas exchange
Author(s) -
Grimoldi Agustín A.,
Kavanová Monika,
Lattanzi Fernando A.,
Schäufele Rudi,
Schnyder Hans
Publication year - 2006
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2006.01853.x
Subject(s) - respiration , photosynthesis , perennial plant , lolium perenne , biology , carbon dioxide , isotopes of carbon , botany , agronomy , zoology , ecology , total organic carbon
Summary• Effects of the arbuscular mycorrhizal fungus (AMF) Glomus hoi on the carbon economy of perennial ryegrass ( Lolium perenne ) were investigated by comparing nonmycorrhizal and mycorrhizal plants of the same size, morphology and phosphorus status. • Plants were grown in the presence of CO 2 sources with different C isotope composition (δ 13 C −1 or −44). Relative respiration and gross photosynthesis rates, and belowground allocation of C assimilated during one light period (‘new C’), as well as its contribution to respiration, were quantified by the concerted use of 13 CO 2 / 12 CO 2 steady‐state labelling and 13 CO 2 / 12 CO 2 gas‐exchange techniques. • AMF ( G. hoi ) enhanced the relative respiration rate of the root + soil system by 16%, inducing an extra C flow amounting to 3% of daily gross photosynthesis. Total C flow into AMF growth and respiration was estimated at < 8% of daily gross photosynthesis. This was associated with a greater amount of new C allocated belowground and respired in mycorrhizal plants. AMF colonization affected the sources supplying belowground respiration, indicating a greater importance of plant C stores in supplying respiration and/or the participation of storage pools within fungal tissues. • When ontogenetic and nutritional effects were accounted for, AMF increased belowground C costs, which were not compensated by increased photosynthesis rates. Therefore the instantaneous relative growth rate was lower in mycorrhizal plants.