An investigation of the karyotypes of four species from the genera Setcreasea, Spironema and Tradescantia (Commelinaceae)

Abstract

An investigation was conducted on the number and morphology of the chromosomes of four species from the family Commelinacene: Spironema fragrans Lindl., Setereasea purpurea Boom, Tradescantia albiflora Kunth. and Tradescantia blossfeldiana Mildbr. It was found that the karyotype of Spironema fragrans Lindl. was 2n = 12 chromo­somes whose total length was 6.9-13.7 µm and the formula of the karyotype was: 2m+2sm +2m+2t+2st^sat +2st Setcreasea purpurea Boom. had 2n = 24 chromosomes, 9.1-12.1 µm in length and the centromere positioned as represented by the formula 24m. The karyotype of Tradsescantia albiflora Kunth. had 2n = 60 chromosomes whose lengths ranged from 1.4 to 4.5 µm, and is described by the formula: 4sm+6m+10st+10sm+10m+20sm. The complex of chromosomes from Tradescantia blossfeldiana Mildbr. consisted of 2n = 60. Their length was 1.3-4.8 µm. The morphological types of the chromosomes are represented by the formula 6st+2m+2sm+6st+2sm+12m+10M+l4m+6sm. It is suggested on the basis of mor­phological analysis of chromosomes that Setereasea purpurea Boom is a tetraploid species and Trudescantia albiflora Kunth. and T. blossfeldiana Mildbr. are decaploids.