Photosynthesis and Nitrogen Fixation in Soybean Exposed to Nitrogen Dioxide and Carbon Dioxide
- Gian Gupta *,
- Yuncong Li and
- Ravinder Sandhu
‘Williams-82’ Soybean [Glycine max (L.) Merr.] plants, at the flowering stage, were exposed to NO2 (0.1 µmol mol−1, 7 h d−1) and CO2 (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 NO2 (with 350 µmol mol−1 CO2) 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 CO2 (in the absence of NO2). 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 NO2 was reduced by the inhibitory impact of CO2 on the parameters studied.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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