Effects of Double CO2 and O3 on Growth and Yields in Soybean
CO2和O3浓度倍增及复合效应对大豆生长和产量的影响

The effects of doubled CO2 and O3 interaction on growth and yields in soybean were investigated in the open top chamber for the first time. Increasing CO2 can promote roots growth. The ability of nitrogen fixation enhanced. Plant height and base diameter increased. There are a little effect on the development stage, green leaf number and leaf area. Double O3 concentration inhibited roots and stems growth. The ability of nitrogen fixation decreased. Green leaf number and leaf area decreased and advanced senescence course. This experiment also indicated that CO2 enhancement could relax the injury and inhibition by O3 to soybean seedling. The differences of growth and the ability of nitrogen fixation in soybean between lasted double CO2 and control are less than that of single O3 concentration. Stimulation and dose-effect of increasing CO2 and O3 concentrations to soybean gradually induced more serious damage in the development late. Green leaf number and leaf area decreased. The ability of nitrogen fixation increased markedly.