| The environment is the basis for Human to the survival and development. The environment issues have become the focus of attention. As the rapid development of industry, people's demand for energy and natural resources are increasing. So that the concentration of the harmful gases in the atmosphere become higher and higher, leading to air pollution problems more serious, which bring serious influences to the ecological environment. Environmental stress makes increasement of reactive oxygen species in plant cells,which causes metabolism imbalance of reactive oxygen species and results in a series of poison in cells.Three-year-old seedlings of Acer ginnala was chosen as materials in this experiment,by dynamic system fumigation treatment at different single-gas SO2 or Cl2 concentrations levels and with different time stress, and in the mixture-gas of SO2 and Cl2 treatments. The purpose is to study the trends of activities of SOD,CAT,POD,PPO, APX and GR in the leaves, and to research the expression of isozymes gene.We also tested the content of MDA.The main results of this research are as follows:expression of interersted genes1.In single-gas SO2 treatments,as the increasing of SO2 concentration,the activities of PPO and APX are appeared decreasing trends. While,the activities of SOD,CAT,POD and GR are appeared increasing and then decreasing trends, GR appeared a steady decreasing trend.In time treatments,as the increasing of time treatment,the activities of CAT and GR increased gradually and then decreased, but SOD,POD, PPO and APX activities are appeared decreasing trends, while SOD and GR activities are changing little. As the increasing of gas concentration and time treatment, MDA content were increasing.2.In single-gas Cl2 treatments,as the increasing of Cl2 concentration,the activities of CAT,POD and GR appeared increasing and then decreasing trends,but GR activity changed little. The activities of SOD, PPOand APX appeared decreasing trends. In time treatments,as the increasing of treatment time,the activities of CAT and POD increased gradually and then decreased,but SOD,PPO and APX activities appeared decreasing trends,while GR activity were changing little. As the increasing of gas concentration and time treatment, MDA content were increasing.3.In the mixture-gas of SO2 and Cl2 treatments,according to different proportions of mixed gas, the changing trends of various kinds of protective enzymes were inconsistent. When the SO2 concentration not changed and increased the Cl2concentrations, the decreased rate of the change of the protective enzyme activity is far greater than that the Cl2 concentrations not changed and increased the SO2 concentration. MDA content increased..Under the three kinds of treaments,the degrees of inhibition were different, from strong to weak as follows:the mixture-gas of SO2 and Cl2 treatment>single-gas Cl2 treatment>single-gas SO2 treatment. 4.In gas SO2, gas Cl2 stress and the mixture-gas of SO2 and Cl2 treatments, as the increasing of gas concentration and time treatment, protective enzyme isozymes do not have specificity band. But in each of the band, the dyeing intensity changed obviously. The result showed the change of isozyme exists certain correlation with the protective enzyme activity.5. In one word, SOD,CAT and GR in the leaves of Acer ginnala can clear away ROS, and resist SO2 and Cl2 effectively. The increment of MDA content in single-gas Cl2 stress was higher than the increment of MDA content in single-gas SO2 stress. The show that the resistance of Acer ginnala to SO2 is much stronger than that of Cl2.Under the same gas concentration stess, the degrees of inhibition were different, from strong to weak as follows:the mixture-gas of SO2 and Cl2 treatment>single-gas Cl2 treatment>single-gas SO2 treatment.The protective enzyme activity have inseparable relationship with its resistance. The shade of dyeing intensity to isozyme band have close relationship with the level of protective enzymes. |
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