Metallicity-dependent spectral evolution
  We have studied the spectral evolution of stellar populations in function of their heavy element content and star formation, using Geneva and Padova stellar track sets, both covering a number of metallicities, and Kurucz grid of stellar atmospheres. The general trend is the progressive growth of absorption and decline of flux towards shorter, UV-wavelengths, with increasing metallicity, and increase of infrared flux. Our models help to quantify given theoretically quite obvious effect. Presented results of integration of flux in different regions indicate, that with a change of metallicity from Z=0.001 to Z=0.04 total amount of radiation energy emitted in the shortest wavelength region by a stellar population during its lifetime diminishes typically by a factor ~10, with the corresponding typical increase in the infrared about 1.5-2 times. These numbers are quite independent on the actual IMF slope values under the assumption of identical slopes. 
P.Traat (Obs Tartu)