PROTEOMIC ANALYSIS AND PEROXIDASE ACTIVITY IN Aster tripolium UNDER OXIDATIVE STRESS IN AMBIENT AND ELEVATED CO2

Abstract

The combined effects of NaCl-salinity and elevated CO2 on the polypeptide levels in leaves of Aster tripolium grown under ambient (ca. 370 ppm) and elevated (520 ppm) CO2 in different concentrations of saline irrigated water were examined by two-dimensional polyacrylamide gel electrophoresis. Silver nitrate stain gels were analyzed to identify changes that resulted when plant grown in the presence of 375 mM NaCl at ambient CO2 level. The protein patterns for control and salt-stressed seedlings were qualitatively changed. This observation was mainly noticeable in young leaves which was not exposed to salinity stress. It is shown more polypeptide proteins through wide range of pH. In contrary, leaves exposed to salinity stress revealed narrow polypeptide pH range proteins. Also, the control old leaves which was not exposed to salt stress showed limited pH range and lower polypeptide numbers compared to young leaves. The effect of NaCl on peroxidase activity under 0,125,250, 375 and 500 mM NaCl was studied at the ambient CO2 and elevated CO2 levels. Peroxidase activity increased under NaCl salinity and the degree of elevation in the activity was salt concentration dependent. Nevertheless, a great activity was recorded in stressed leaves comparison to control leaves. Furthermore, peroxidase activity was changed to lower activity in high level of CO2 corresponding to ambient level of CO2 The study revealed that Aster tripolium showed distinct differences in peroxidase activity behaviour under different environmental condition. The correlation coefficient between peroxidase activity under different salinity stress and high level of CO2 was strongly negative correlation, which means that plant will not reveal stress response of peroxidase activity under elevated CO2. Lowering of peroxidase activity under both salinity stress and higher level of CO2 indicate to the important and unique role of halophyte i.e. Aster tripolium in this study for removing, cleaning and remedy environmental air from higher level of CO2 and decrease the green house effect.