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Inoculation with an enhanced N 2 ‐fixing B radyrhizobium japonicum strain ( USDA 110) does not alter soybean ( G lycine max M err.) response to elevated [ CO 2 ]
Author(s) -
Sanzsáez Álvaro,
Heath Katy D.,
Burke Patricia V.,
Ainsworth Elizabeth A.
Publication year - 2015
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12577
Subject(s) - rhizobia , inoculation , nitrogen fixation , biology , human fertilization , photosynthesis , bradyrhizobium japonicum , competition (biology) , symbiosis , rhizobiaceae , agronomy , horticulture , chemistry , zoology , botany , bacteria , genetics , ecology
This study tested the hypothesis that inoculation of soybean ( G lycine max M err.) with a B radyrhizobium japonicum strain ( USDA 110) with greater N 2 fixation rates would enhance soybean response to elevated [ CO 2 ]. In field experiments at the S oybean F ree A ir CO 2 Enrichment facility, inoculation of soybean with USDA 110 increased nodule occupancy from 5% in native soil to 54% in elevated [ CO 2 ] and 34% at ambient [ CO 2 ]. Despite this success, inoculation with USDA 110 did not result in greater photosynthesis, growth or seed yield at ambient or elevated [ CO 2 ] in the field, presumably due to competition from native rhizobia. In a growth chamber experiment designed to study the effects of inoculation in the absence of competition, inoculation with USDA 110 in sterilized soil resulted in nodule occupation of >90%, significantly greater 15 N 2 fixation, photosynthetic capacity, leaf N and total plant biomass compared with plants grown with native soil bacteria. However, there was no interaction of rhizobium fertilization with elevated [ CO 2 ]; inoculation with USDA 110 was equally beneficial at ambient and elevated [ CO 2 ]. These results suggest that selected rhizobia could potentially stimulate soybean yield in soils with little or no history of prior soybean production, but that better quality rhizobia do not enhance soybean responses to elevated [ CO 2 ].