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COMPARATIVE WATER RELATIONS AND PHOTOSYNTHESIS OF MYCORRHIZAL AND NON‐MYCORRHIZAL BOUTELOUA GRACILIS H.B.K. LAG EX STEUD.
Author(s) -
ALLEN MICHAEL F.,
SMITH WILLIAM K.,
MOORE THOMAS S.,
CHRISTENSEN MARTHA
Publication year - 1981
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.1469-8137.1981.tb01745.x
Subject(s) - bouteloua gracilis , biology , photosynthesis , transpiration , xylem , stomatal conductance , mycorrhiza , botany , biomass (ecology) , agronomy , symbiosis , bacteria , genetics , grazing
SUMMARY The rangeland grass, Bouteloua gracilis was inoculated with its mycorrhizal symbiont, Glomus fasciculatus , to determine the influence of vesicular‐arbuscular mycorrhizae on water status, stomatal behaviour and photosynthesis as well as gross plant morphology, biomass and phosphorus content. Mycorrhizal infection increased transpiration rates by over 100% with 50 to 70% lower leaf resistances to water vapour diffusion. Leaf xylem pressure was not different between mycorrhizal and non‐mycorrhizal plants indicating that whole‐plant resistance to water transport was reduced by more than 50%. Photosynthetic rates under saturating light conditions increased 68% with infection as a consequence of a 33% reduction in stomatal resistance and a 67% reduction in mesophyll resistance to CO 2 uptake. Mycorrhizal infection did not affect biomass or gross plant morphology after 30 weeks of growth, but increased chlorophyll and phosphate concentrations by 28% and 70% respectively. These physiological changes indicate that mycorrhizae may substantially alter survival ability of Bouteloua gracilis.