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Chromosome variation in Anatolian species of Nonea Medik. (Boraginaceae), with special reference to endemics and N. persica

2003; University of Florence; Volume: 56; Issue: 4 Linguagem: Inglês

10.1080/00087114.2003.10589364

2165-5391

Massimo Bigazzi, Federico Selvi,

Plant Taxonomy and Phylogenetics

Abstract The chromosome complements of five Anatolian species of Nonea Medik., N. intermedia, N. macrantha, N. stenosolen, N. caspica and N. persica, were analysed with traditional staining methods. All except N. persica are invariably diploid taxa, but the first two are based on x = 10, while N. stenosolen and N. caspica on x = 9 and x = 8, respectively. N. persica includes diploid races with 2n = 18 and, more rarely, 2n = 20. Inter- and intrapopulational variation in base number occurs in this polymorphic species (x = 10 and x = 9). Several individuals from the Kars province showed aneusomaty, e.g. co-occurrence in the same root meristem of cells with 2n =19/18 and more rarely 2n = 20/19. The latter number (19) possibly originates through centric fusion of two regular chromosomes. In addition N. persica includes tetraploids and, rarely, hexaploids with 2n = 36 and 2n = 54, respectively. In East Anatolia polyploids are sympatric with diploids, suggesting that they have a polytopic and recurrent formation through autopolyploidy. Finally, a decaploid population with 2n = 100, the highest number observed in Nonea, was documented. A variable number of supranumerary B-chromosomes occurred in N. stenosolen and some 2n = 36 and 2n = 54 cytotypes of N. persica. Our data support x = 10 as primary haploid number in Nonea, descending dysploidy as a process leading to x = 9, 8 and 7, and polyploidy as a major mechanism of speciation in the perennial species of this genus. Key words: aneusomatyB-chromosomesBoraginaceaecytosystematicsdisploidyendemic Anatolian floraNoneapolyploidy