A Diploid Plant with only One Nucleolus and its Bearing on the Balance Hypothesis of Nucleolar Chromosome

Abstract

1) The relation between nucleolus and nucleolar chromosomes in polyploid series of Scilla japonica (18=B₂B₂, 26=B₁B₂B₂, 34=B₁B₁B₂B₂, 35=B₁B₂B₂B₂) was explained by the balance hypothesis of nucleolar chromosome.
2) Paris hexaphylla (2n=15) is triploid and has ogle sat- and two nucleolar chromosomes, corresponding to three nucleoli at telophase. The satellite in Paris consists of heterochromatin and seems to be genetically inert.
3) Brodiaea uniflora (2n=12) is diploid and has only one nucleolus, corresponding to one sat-chromosome with a long stalk. This fact seems favourable for the balance hypothesis of nucleolar chromosome.