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Journal of Environmental Quality Abstract -

Nitrogen Dioxide Effects on Photosynthesis in Soybean


This article in JEQ

  1. Vol. 17 No. 1, p. 143-146
    Received: June 25, 1987

    * Corresponding author(s):
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  1. Sashikala Sabaratnam,
  2. Gian Gupta * and
  3. Charles Mulchi
  1. Dep. of Agronomy, Univ. of Maryland, College Park, MD 20742.



Very little information is available on the effects of nitrogen dioxide (NO2) on photosynthesis in soybean [Glycine max (L.) Merr.]. This investigation was undertaken to study the effects of NO2 (0.0, 0.1, 0.2, 0.3, and 0.5 µL/L) on net photosynthetic rate (PN), stomatal resistance (SR), and dark respiration rate (DR) of soybean cultivar Williams treated 7 h/d, for 5 d in a controlled environment. Measurements of PN, SR, and DR were made both immediately and 24 h after the termination of exposure, using a LICOR 6000 Portable Photosynthesis system. Treatment effects on PN and DR were statistically significant. Increases of 18 and 23% in PN were observed immediately following exposure to 0.2 µL/L NO2 and after a 24-h recovery period. With the 0.5 µL/L NO2 treatment reductions in the PN of 23 and 50% were observed immediately after exposure and following the 24-h recovery period. Dark respiration rates of leaves treated with NO2, 0.2 µL/L, were 13 and 46% higher than the control immediately after the exposure and after the 24 h recovery. Exposure to 0.2 µL/L of NO2 had a stimulating effect whereas 0.5 µL/L of NO2 inhibited photosynthesis in soybean.

Contribution from the Dep. of Agric. Sci., Univ. of Maryland Eastern Shore, Princess Anne, MD.

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