Abstract: Three kinds of plant treated with sulphurous acid were used to study the protective function of phosphate buffer in respect of membrane lipid peroxidation. The result shows that after the plants were sprayed with phosphate buffer, they had an obvious protective function to the harm caused by sulphurous acid. The phosphate buffer could stabilize the cell membrane structure, decrease the content of MDA, and increase the degree of chlorophyll-protein binding. It also had a coordinated effect on SODactivity with sulphurous acid at low concentration. The protective effect of phosphate buffer was different with plant species. In the same polluted environment, the plants with high MDAconcentration and low chlorophyll binding degree had greater protective function, and the effect order of tested plants was Ginkgo biloba>Forsythia suspensa>Triticum aestivum.

Key words: Phosphate buffer, Sulphurous acid harm, Membrane lipid peroxidation, Chlorophyll binding degree, food web, stable isotope, trophic level, Dalian marine area