Two-Dimensional Gel Electrophoresis of Polypeptides from Stems, Roots, Leaves, and Rhizophores of Selaginella kraussiana

Two-dimensional gel electrophoresis of polypeptides from stems, leaves, roots, and rhizophores of the vegetative sporophyte of Selaginella kraussiana shows unique patterns. Over 600 polypeptides can be resolved; 18% are common to the four organs. Stems yield the highest percentage (23%) of unique polypeptides, while only 3% of leaf polypeptides are unique. Pair comparisons of patterns of the four organs show the greatest similarity between stems and rhizophores: 58% common polypeptides. Of the total polypeptides of rhizophores and roots, 42% are similar. Stems and rhizophores have the largest number of polypeptides unique to a pair of organs, while rhizophores and roots have fewer unique polypeptides. These results indicate that, at the abundant gene-product level, stems and rhizophores are more similar than rhizophores and roots. These results contradict views that the rhizophore is essentially an aerial phase of the root system and that rhizophores and roots are homologous organs.