Aneuploid Variation of Chromosome Number in the Somatic Cells of Piper magnificum Trel.

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Aneuploid variation of chromosome number in somatic cells at growing root tips of Piper magnificum Trel., a South American Piper species of ornamental value is reported. Of the total 142 mitotic metaphase plates examined, about 62% of the cells were having normal chromosome number of 2n=26. The variations observed were 2n=22, 24, 25, 27, and 28 among which 2n=24 was the most frequent (27.46%) and others were in less than 5.0%. Higher frequency of the cells with 2n=24 is attributed as a reason for the dual chromosome numbers (2n=24 and 2n=26) reported for the species. The role of precocious segregation of chromosomes and lagging during anaphase in generating aneuploid variation of chromosomes is discussed. This is the first report of such variation in P. magnificum.