Abstract
In order to obtain useful information about the mechanism of damage caused by excess heavy metals to mulberry growth, studies were carried out on the effects of cadmium, copper and nickel on photosynthetic rates and morphogenesis in mulberry leaves. Each heavy metal inhibited markedly increase of dry weight of newly formed leaves after the beginning of treatment at high concentrations. Copper showed strong reductive effects on specific leaf weight. Cadmium, copper and nickel reduced photosynthetic rates at high concentrations. Chlorosis occurred in middle leaves due to cadmium and in middle or lower leaves due to nickel. A reduction of chlorophyll content was induced in mulberry leaves at high concentrations of cadmium and nickel. Stomatal formation and development of leaf veins were suppressed at high concentrations of copper and cadmium. But thickened growth of mesophyll was slightly suppressed by nickel.
