Title : Preliminary data regarding the karyotype of some spontaneous medicinal plants from North-East of Romania
The karyotype studies represent the first and useful step that provides the cyto-taxonomic status of the species in order to establish the phylogeny. With this technique it may be possible to discover installation of some numerical and morphological aberrations on the chromosome level. Also, cytogenetic studies aimed at establishing the number of chromosomes of the species, elucidating their conformation and ordering them in karyotype and idiogram, are of particular importance in initiating and directing of the plant breeding amelioration for obtain the hybrids with agricultural and economic role (salt and drought-tolerance/resistance, etc.). According with above mentioned, the aim of present study was to determine the somatic chromosome number, analysis of the morphological features of mitotic chromosomes, construction
of karyotypes and idiogram of five spontaneous medicinal plants, such as: Anthemis tinctoria L., Cichorium intybus L. Datura stramonium L., Echium vulgare L., and Humulus lupulus L. 1. For Anthemis tinctoria L. (2n=18), according to the ratio between long and short arm, we established the following three chromosome types: median - m (pairs I, III, IV and VII), arms ratio between 1.10 (I) and 1.42 (VII); submedian - sm (II, V, VI, VIII) with arms ratio 1.51 (VI) and 2.93 (V); subtelocentric - st (IX) having 3.10 arms ratio. No secondary constriction was observed. 2. The diploid set of Cichorium intybus L. was 2n=18 chromosomes, having small dimension, according to literature data (Bernardes et al., 2013). 3. In the case of Datura stramonium L. (2n=24), we established two morphological types of chromosomes: median - m (pairs I, II, IV, V, VI, VII, VIII, IX and XI) and submedian - sm (pairs III, X and XI), this species having symmetrical karyotype. Flow cytometric analysis identified also diploid and tetraploid plants of Datura stramonium calus and hairy root in vitro cultures (Weber et al., 2008). 4. Echium vulgare L. is a tetraploid species (2n=4x=32) with very small chromosomes. It is considered pseudometallophyte plant which commonly occurred on dry, coarse textured soils as well as on heavy metal contaminated
substrates. Comparatively study between E. vulgare originating from Zn-Pb mining and smelting waste deposits and from uncontaminated soil showed increasing of the genetic diversity in the plants from contaminated soil (Dresler et al., 2015). 5. Humulus lupulus L. (2n=20) is a plant with heteromorphic sex chromosomes, the genotypes carrying XX or XY chromosomes correspond to female and male plants, respectively (Divashuk et al., 2011). In our study we identified also diploid (2n=20, XX) and aneuploid (2n=21, 26 and 27 chromosomes) metacentric – M, r=1.0, median – m, and submedian - sm. Very recent studies of meiotic chromosomes (Easterling et al., 2018) revealed segregation distortion in H. lupulus, including aneuploidy, segmental aneuploidy, or chromosome rearrangements. This classical cytogenetic investigations will be must completed and correlated with some advanced approaches such as DAPI banding, fluorescence in situ hybridization (FISH) or flow cytometric determinations in order to formulation of an accurate view on the karyotype evolution of some medicinal plants from North-East Region of Romania.
This work was supported by Romanian Ministry of Research and Innovation (25N/2019 and 22PFE/2018 projects).