Chromosome Studies in the Family Magnoliaceae

Abstract

Chromosome study has been carried out on ten species belonging to three genera of the family Magnoliaceae, with the application of improved techniques. Only two species, namely Magnolia liliflora (2n=76) and M. grandiflora (2n=114) show high chromosome numbers, the rest showing 2n=38 chromosomes. The general features include uniformity of chromosome number, graded karyotypes, with mostly metacentric chromosomes and the size ranging from medium to small. The plants, with high chromosome number in the polyploid species, have long chromosomes and show no reduction in chromosome size. The species differ from one another in the type and number of chromosomes with secondary constrictions. Minor structural alterations of chromosomes have probably played the most important role in the evolution of genus and species rather than polyploidy and aneuploidy.