Effects of enhance of UV-B radiation and O3concentration on dry matter and yield of soybean

During the last several decades, the concentration of stratospheric ozone (O3) significantly reduced, and further caused an increment in ultraviolet-B (UV-B) radiation approaching to the earth surface. Both tropospheric O3and UV-B have adverse effects on the yield and safety of crops. The combination of increased tropospheric O3concentration and elevated UV-B could cause reduction in biochemical and physiological characteristic of economic plants and crops. To reveal the effects of enhanced UV-B and O3concentration on dry matter and yield of soybean (Glycine max, Yellow August), open-top chambers (OTCs) and UV lights were used to simulate the enhanced O3concentration and supplemental UV-B radiation. The results showed that, compared with the control group CK (natural solar UV-B irradiance, ambient air with approximately 50 nL/L O3), the plant height of T1 (10% higher level of UV-B intensity, ambient air with approximately 50 nL/L O3), T2 (100 nL/L O3and 10% higher level of UV-B intensity) and T3 (150 nL/L O3and 10% higher level of UV-B intensity) decreased by 12.73%, 12.78% and 14.15%, respectively; Chlorophyll content decreased by -1.16% (P>0.05), 34.20% (Pn) fell 11.50%, 46.65% and 48.58%; Dry matter accumulation decreased by 31.02% (P3and UV-B had negative effects on soybean growth and dry matter accumulation, and the composite group had a significant adverse impact on soybean growth. Soybean yield was strongly inhabited under the combination of enhanced O3and UV-B radiation by showing the reduction of grain numbers and grain weight.