KARYOTYPES AND FISH DETECTION OF 5S AND 45S RDNA LOCI IN CHINESE MEDICINAL PLANT ATRACTYLODES LANCEA SUBSP. LUOTIANENSIS: CYTOLOGICAL EVIDENCE FOR THE NEW TAXONOMIC UNIT

摘要

Atractylodes lancea (Thunb.) DC. in the Asteraceae family produces the atractylodes rhizome which is widely used asa traditional medicine in China. The subspecies A. lancea (Thunb.) DC subsp. Luotianensis distributed in mountainousLuotian and Yingshan regions in Hubei Province presented distinct morphology and superior medicinal quality. This studyfirstly reported the chromosome karyotype of this subspecies and the detection of 5S and 45S rDNA loci by fluorescent insitu hybridization. The karyotype was 2n=24=12m+12sm (2SAT). A single locus of 5S rDNA and two loci of 45S rDNAloci were identified and separated on different chromosomes. Its one pair of the satellited chromosomes rather than two pairsin other Atractylodes species yet still with 2n=24 occurred likely after its occupation of this geographic location. Theevidence of karyotype differentiation of this subspecies native to the area is useful for elucidating the genome structure andidentifying chromosomes.