Abstract:
During the last several decades, the concentration of stratospheric ozone (O
3) significantly reduced, and further caused an increment in ultraviolet-B (UV-B) radiation approaching to the earth surface. Both tropospheric O
3 and UV-B have adverse effects on the yield and safety of crops. The combination of increased tropospheric O
3 concentration 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 O
3 concentration on dry matter and yield of soybean (Glycine max, Yellow August), open-top chambers (OTCs) and UV lights were used to simulate the enhanced O
3 concentration and supplemental UV-B radiation. The results showed that, compared with the control group CK (natural solar UV-B irradiance, ambient air with approximately 50nL/L O
3), the plant height of T1(10% higher level of UV-B intensity, ambient air with approximately 50nL/L O
3), T2(100nL/L O
3and 10% higher level of UV-B intensity) and T3(150nL/L O
3and 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% (P<0.05) and 57.38% (P<0.05); Net photosynthetic rate (Pn) fell 11.50%, 46.65% and 48.58%; Dry matter accumulation decreased by 31.02% (P<0.05), 61.35% (P<0.05) and 67.53% (P<0.05) respectively; Yield reduced by 4.13%, 54.09% and 79.34% respectively. Both O
3 and 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 O
3and UV-B radiation by showing the reduction of grain numbers and grain weight.