Responses of Soybean to Oxygen Deficiency and Elevated Root‐zone Carbon Dioxide Concentration

Soybean is injured by elevated root-zone CO₂ concentration

Soybean is very tolerant to excess water and anaerobiosis. However, Boru et al. (pp. 447-453) show that if anaerobic root-zones also contain elevated CO₂ concentrations, injury to the plant results. In contrast to soybean, rice is impervious to this combination of no oxygen and elevated root-zone CO₂. It is suggested that the relative susceptibility of soybean to soil flooding, compared with that of rice, may be an outcome of its greater sensitivity to CO₂.