Immunological Studies on the Tuber-bearing Solanums

Abstract

Many improvements have been made in recent years in serological techniques which give them a sounder basis and make them more likely to provide information of taxonomic importance. The Ouchterlony double diffusion technique and immuno-electrophoretic analysis are here described, together with new ways of analysing the results by characterization of the individual antigens. It was shown experimentally with two species that the normal range of variation in temperature or light intensity during storage has no significant effect on the antigen content of the tubers. The antigenic proteins of Solanum tuberositm occur chiefly in the phloem and in the peripheral cortex of the tuber. By immuno-electrophoresis and zone electrophoresis, it was shown that the antigens correspond to the major protein fractions of the extracts. Organ specificity of antigens was demonstrated, in that with an antiserum to one organ of one species, extracts of other organs of the same species reacted weakly, whereas extracts of the same organ of other species reacted strongly. An investigation of the tuber antigens of some South American species showed a general uniformity, as reported by previous workers. However some differences common to all clones of both subspecies of S.commersoniiybut not to any other species of the series Commersoniana, were found.