Abstract
An open‐top field chamber experiment was conducted to evaluate the impact of Molybdenum (Mo) addition to soil on the physiological changes in soybean (Glycine max L. Merrill) exposed to ozone (O3). Plants grown with Mo (0, 1.0, or 2.0 mg kg"1 soil dry weight) were exposed to O3 (O, 0.06, or 0.12 μmol mol‐1) in open‐top field chambers for 12 h d‐1 for 21 d with a N‐free fertilizer, during the sensitive growth stage (R2). The rate of photosynthesis (PN), specific root nodule nitrogenase activity (SNA), leaf nitrogen (N), chlorophyll (chl‐a, chl‐b) and biomass of soybean were measured. The increase in O3 levels significantly reduced PN, SNA, leaf‐N, chl‐a, chl‐b, and biomass. Addition of Mo increased leaf‐N, shoot, root, and nodule dry weights but did not change PN, SNA, or chlorophyll. The addition of Mo (2 mg kg ‐1) helped in significantly increasing PN and chlorophyll in the presence of 0.06 umol mol‐1 O3 but no change was observed in the presence of 0.12 μmol mol‐1 O3.
Notes
Agricultural Research and Education Center, University of Florida, 2199 S. Rock Road, Fort Pierce, FL 34545.