Reversed-phase High-performance Liquid Chromatography and Scanning Electron Microscopy

The zein proteins of eight opaque maize mutants were examined by reversed-phase high-performance liquid chromatography (RP-HPLC) and the microstructure of their endosperms by scanning electron microscopy (SEM). The opaque (0) mutants included 01, 05, 09) 010) 011) hI, Oh43JlI and V\ 64AJll. In these opaque mutant maize kernels, the proportion (%) of ex-zein, the major component of the alcohol-extractable storage proteins, resembled that present in normal maize lines. This is in contrast to the 50% reduction observed for opaque-2 (02) mutants. Whereas the 02 genotype has been found to contain protein bodies of reduced number and size, those in the non-02 opaque mutant kernels were of similar size to those in normal lines and were present in clusters in the endosperm. In non-02 opaque mutants, the protein compositions of the endosperms resembled those of normal maize lines. Therefore, the number of protein bodies present in the endosperm and their zein compositions do not appear to be responsible for hardness in normal maize kernels.