Background: Gastrodia elata Blume is a saprophytic perennial plant in the Orchidaceae family, because of its agricultural and medicinal effectiveness, researchers focus on its genome and chemical components. However, cytogenetic information based on the chromosome structure and composition to construct chromosomal backbone for genome sequencing research and for the development and breeding of plants is very limited. Methods and Results: We determined the metaphase chromosome composition of the G. elata genome by fluorescence in situ hybridization (FISH) using 5S and 45S rDNAs and telomeric repeat probes. The nuclear genome of G. elata was organized into 2 n = 36, with relatively small (2.71 - 5.50㎛)chromosomes that showed gradual decrease in size. Conglutination phenomenon was observed among the metaphase chromosomes, and it was distinguished from that in other plant metaphase chromosome spreads. One pair of signal was detected for each 5S and 45S rDNA in the pericentromeric region and interstitial region on the short arm of chromosomes 10 and 4, respectively, and telomeric DNA signals were detected in the terminal region of most chromosomes. Conclusions: To our knowledge, this is the first FISH chromosome composition result in G. elata and could be useful in more comprehensive molecular cytogenetic and genomic analyses as well as breeding programs of the medicinal plant G. elata.

The growth charateristics and karyotypes of Aster spathulifolius collected from 5 sites including coastal and island region on the Korean peninsula, were analysed. Several morphological characteristics of the plants such as leaf length, leaf width, top internode, medium internode, spike branching, flower diameter, number of petal, leaf color, leaf form, stem and leaf hair, viscosity, and serration of the plants were distinctly different depending on the native region from which they were collected. Karyotypic analysis showed that the chromosome number was all diploid (2n=18), with one pair of submetacentric satellite chromosomes. The chromosome composition included 7 pairs of metacentric chromosomes and 2 pairs of submetacentric chromosomes in all plants. However, chromosome order and the ranges of the chromosome lengths were a little different from plant to plant according to their native growing regions. The plants from Geoje-Do especially showed large differences in the chromosome lengths between the longest and the shortest compared to the plants from other places. This results provide important data to support the classification of the species into several sub-species.