Combination Effects of Elevated O_3 and Enhanced UV-B Radiation on Biomass and Yield of Soybean

Responses of soybean(Glycine max,Bayuehuang) to enhanced ozone,supplemental UV-B radiation and in combination,were investigated in this paper by using open-top-chambers(OTCs).Four treatments were exposing to unfiltered air(CK),ozone content with 100nmol/mol(T1),UV-B radiation levels with 10% higher than control group(T2) and combination treatment(T3).The results showed that the single factor ozone or UV radiation had different degrees of negative effects on soybean height,leaf area,stem dry weight and other biomass.Combined impact of two factors was inconsistent,antagonism was showed mostly form branch period to pod bearing period,on the contrary,synergy was in the mayor role in the end of period fertility.The change of stem allocation index was relatively small,leaf and root allocation index was gradually reduced,and pod distribution index was rising rapidly under different treatments in the whole growth period.Thus,the single-factor stress of ozone or UV-B radiation on soybean biomass and yield was different degrees of negative effects,while the interactived effects were not equal to addition.