Comparative protein population investigation of the Alnus serrulatarugosa complex

The data from electrophoretic and serological studies with proteins extracted from pollen from: eight populations of the Alnus serrulata-rugosa complex indicate that some bands of the protein pattern (Type A bands) were consistently present in all the samples collected from various populations. The Type A band pattern was not influenced by individual genotypes or environmental differences. Attempts to use bands other than those of Type A in the characterization of populations within the complex did not prove valuable. The importance of using a sample size large enough to cope with the problem of variability within a population was revealed. The data obtained by the use of qualitative serological techniques (Ouchterlony method) agreed with those obtained by the quantitative turbidimetric procedure (Boyden procedure). Serology differences among populations within the complex were not detected. However, marked differences were detected when compared to Betula populifolia, another genus in the same family. All but one sample of seeds of the complex studied revealed 95% sterility because of abnormal embryo development. Viability pollen tests of the 14 samples from the eight populations revealed 94–99% viability. We believe that a taxonomic treatment which designates this complex as one species with varieties or subspecies is the best interpretation of the data available from diverse disciplines and several independent studies.