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Photosynthesis and Nitrogen Fixation in Soybean Exposed to Nitrogen Dioxide and Carbon Dioxide
Author(s) -
Gupta Gian,
Li Yuncong,
Sandhu Ravinder
Publication year - 1992
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1992.00472425002100040016x
Subject(s) - carbon dioxide , photosynthesis , chemistry , nitrogen , nitrogenase , kjeldahl method , acetylene , nitrogen fixation , botany , glycine , horticulture , biology , biochemistry , organic chemistry , amino acid
‘Williams‐82’ Soybean [ Glycine max (L.) Merr.] plants, at the flowering stage, were exposed to NO 2 (0.1 µmol mol −1 , 7 h d −1 ) and CO 2 (450 µmol mol −1 , 12 h d −1 ) for 5 d singly and in combination in open‐top field chambers. The rate of photosynthesis (PN), specific root nodule nitrogenase activity (SNA), and leaf N were measured after exposure using the LICOR 6200 Portable Photosynthesis system, the acetylene‐ethylene reduction method, and the Kjeldahl digestion, respectively. The plants exposed to NO 2 (with 350 µmol mol −1 CO 2 ) showed significantly higher PN, SNA, and N compared with the control plants. The SNA and N were reduced, with no change in PN on exposing the plants to CO 2 (in the absence of NO 2 ). When the plants were exposed to a combination of these two gases, SNA was increased but the PN and N did not change. The stimulatory effect of NO 2 was reduced by the inhibitory impact of CO 2 on the parameters studied.