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In this paper, open-top chambers (Open-top chamber, referred to as OTC) method to study analyzed the O 3 concentration (80 ± 10 nL · L -1 and 110 ± 10 nL · L -1 ) on soybean (Glycinem ax.) photosynthesis, membrane lipid peroxidation, reactive oxygen metabolism, osmotic adjustment, antioxidant protection system and the protection of isoenzymes impact protection system and reveals the soybean isoenzymes protection against O 3 concentration degree of response mode and response, from the molecular level for the plants to O 3 Elevated concentrations of adaptation mechanisms foundation. The results are as follows: O 3 concentration can significantly reduce soybean leaf Chl (ab) and Chla content and O 3 stress the greater the intensity, Chl (ab) and Chla the lower the content. In addition to individual periods O 3 concentration was 80 ± 10 nL · L -1 CK treatment slightly outside, O 3 Stress treatment Chlb content and Chla / b were lower than CK, and two high concentrations of O 3 treatment compared to the whole growth period, no significant change in the law. It can be seen that high concentrations of O 3 treatment on soybean leaf chlorophyll content expressed as inhibition. O 3 concentration can significantly reduce soybean leaf Pn, Gs, Tr, description O 3 concentration on soybean leaf net photosynthetic rate, stomatal conductance and transpiration rate had a negative effect, and O 3 The higher the concentration, the negative effect is more obvious. Different O 3 concentration on soybean leaves Ci affected differently, when O 3 concentration was 80 ± 10 nL · L -1 , the soybean leaves Ci in branching and flowering stages than CK, the pod and seed filling stage is higher than CK; when O 3 concentration of 110 ± 10 nL · L -1 , the soybean leaves Ci in the whole growth period were lower than CK. O 3 concentration can significantly increase soybean leaf relative conductivity and MDA content, you can improve soybean leaves O 2 ? generation rate and H 2 O 2 content. This shows that high concentrations of O 3 Stress can make soybean leaf lipid peroxidation levels increased, increased accumulation of reactive oxygen species, suggesting that high concentrations of O 3 already on leaf cell membrane system produces injury, and O 3 higher concentration of harmful effects on soybean more obvious. O 3 concentration reduces the Car, ASA content. In addition to the high concentration of branched O 3 processing plants to elevated SOD activity in the short-term, high concentrations of O 3 processing plants SOD activity were lower than CK. In addition to the branching stage O 3 concentration was 80 ± 10nL · L -1 processing plants APX activity increased slightly, the high concentration of O 3 Soybean Leaves of POD activity, CAT and APX activity significantly or very significantly. Generally speaking, O 3 concentration on soybean leaves protective substances and protective enzymes damage the overall performance of the role, and the O 3 The higher the concentration, the more harmful effects obvious. O 3 concentration on soybean leaf SOD isoenzymes, POD isozyme, CAT and APX isoenzyme isoenzyme is not reflected in the number of changes with the enzyme, but rather reflect width of the enzyme or the change in brightness, so that the change in the original enzyme activity. SOD, POD, CAT activity and its isoenzyme activity assay results are basically the same, and this isoenzyme activity APX APX activity was measured with inconsistent results. O 3 concentration conditions, compared with the control soybean plants soluble sugars, protein and Pro content with varying degrees of first and then decreased. Showed high concentrations of soybean O 3 has some resistance, but with the ventilation time, the soybean plants are exposed to high concentrations of O 3 stress injury, and this the extent of injury and O 3 concentrations were positively correlated. O 3 concentration on soybean grain yield was obvious. With O 3 concentration, soybean grains per plant, grain weight per plant, seed weight and number of pods per plant decreased, and O 3 concentration more high, the greater the reduction. O 3 concentration conditions, soybean grain yield and CK reached significant or very significant difference. In summary, O 3 concentration can decrease soybean leaf photosynthesis, reduced antioxidant capacity, increased accumulation of reactive oxygen species, so that SOD, POD, CAT activity and isoenzyme activity decreased lipid peroxidation increased, osmolytes accumulation reduced, resulting in lower grain yield of soybean. Generally speaking, O 3 The higher the concentration, O 3 Stress on the harmful effects of soy protection systems more obvious.
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