AbstractIso‐peroxidase (iPOD)‐patterns of Norway spruce clones differing in their relative resistance to air pollution; comparing zymograms during the beginning of the vegetation period 1986.iPOD‐systems of young needles were investigated and characterized by analytically electrofocusing the needle extracts in thin layers of polyacrylamide gels.The zymograms obtained showed that possibly there exists coupling between codon sequences coding for the complex quality “resistance to air pollution” and sequences coding for specific iPOD