Regular Article
New Chromosome Counts in Hesperis L. from Turkey
2020 Volume 85 Issue 1 Pages 41-43
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2020 Volume 85 Issue 1 Pages 41-43
Chromosome numbers of four endemic Hesperis species (H. armena Boiss., H. kotschyi Boiss., H. pisidica Hub.-Mor. and H. thyrsoidea Boiss.) in Turkey have been reported for the first time. All species have 2n=14 chromosomes, except H. pisidica Hub.-Mor. (2n=12). This species is also different from the others because of having satellite. Determining of the basic chromosome numbers x=6 and 7 are consistent with previous reports on Hesperis taxa in Turkey.
Brassicaceae is a large family of major economic importance, containing a wide array of crop plants grown as salads, vegetables, for the oilseed, animal feed and condiments, and several well-known garden ornamental plants such as the wallflower, honesty and aubretia (Heywood 1993, Martin et al. 2009). Members of the family are found in most parts of the world but are mainly concentrated in the north temperate region and more especially in the countries surrounding the Mediterranean basin and in southwestern and Central Asia, where more genera occur than anywhere else in the world (Heywood 1993, Martin et al. 2009). In Turkey, it is represented by 85 genera and 458 species (Al-Shehbaz 2012). The Hesperis species are distributed in the warm climate zone of Eurasia and in the mountainous regions of southern and central Europe, southwest Asia, Caucasus, Russia, western China, and Mongolia. There are about 55 species in the world (Duran et al. 2002, 2003, Duran and Ocak 2005). In Turkey, the Hesperis is represented by 27 species belonging to seven sections, of which 19 species are endemic to Turkey (Aras et al. 2003).
The aims of the present study are to reveal the karyological features of Hesperis species and investigate the degree of chromosomal variation of the studied at the interspecies level.
Four Turkish Hesperis species, e.g. H. armena Boiss., H. kotschyi Boiss., H. pisidica Hub.-Mor. and H. thyrsoidea Boiss. were examined their chromosomes. The examined Hesperis samples were collected at least 10 individuals of each species from various localities in Turkey (Table 1). Mature seeds were selected and periodically germinated for chromosome analysis. Five seedlings were investigated. Vouchers are stored in Selçuk University Science Faculty Herbarium (KNYA), (Table 1). Primary roots of seedlings were pretreated with 2 mM 8-hydroxyquinoline for 8 h at 4°C and then fixed with Carnoy for 24 h at 4°C. The material was hydrolyzed with 5 M HCl for 10 min at room temperature and then stained and squashed in 1% aceto-orcein. The preparations were made permanent according to the method of Bowen (1956). At least 10 metaphases for each species were photographed using an Olympus DP-72 digital camera attached to an Olympus BX53 microscope.
| Species | Locality, altitude and collection date | Voucher |
|---|---|---|
| H. armena | Muğla, Yılanlı Mountain, 1650 m, 09.07.2018 | EŞ-753-HG (KNYA) |
| H. kotschyi | Kırşehir: Kervansaray Mountain, 1650 m, 08.07.2018 | EŞ-751-HG (KNYA) |
| H. pisidica | Antalya: Elmalı, 2100 m, 09.07.2018 | EŞ-754-HG (KNYA) |
| H. thrysoidea | Sivas: Zara–Divriği road, 1600 m, 10.07.2018 | EŞ-755-HG (KNYA) |
The chromosome set of H. armena comprise of 14 chromosomes (Fig. 1A). The chromosome number was reported for the first time. In H. kotschyi the chromosome number was determined to be 2n=14 (Fig. 1B). Our report is the first chromosome study for this endemic species. In H. pisidica the chromosome number was determined to be 2n=12 (Fig. 1C). This species is different from the others because of having a satellite. In H. thyrsoidea the chromosome number was determined to be 2n=14 (Fig. 1D). Our report is the first chromosome study for this endemic species.
Karyological parameters as the characteristic determining the phylogenetic relationship among species is an effective and valid method (Venora et al. 2002). The number and size of chromosomes within the Brassicaceae are quite different for taxa in various genera, and this is important in terms of evolution and systematic evaluation in this family (Karaismailoğlu 2018).
In the Brassicaceae, the chromosome numbers of 1559 of the 3709 species (42%) and 232 of the 338 genera (68%) are known (Warwick and Al-Shehbaz 2006). The basic numbers vary from 4 to 13, but surprisingly, x=8 is observed with a high percentage (37%; Warwick and Al-Shehbaz 2006).
Cytological examinations performed on the taxa of Hesperis showed that the chromosome numbers are 2n=12, 14, 16, 24, 26, and 28 (Manton 1932, Sokolovskaja and Strelkova 1948, Löve and Löve 1956, Löve 1961, Dvořák 1964, 1966, 1973, 1982, Dvořák and Dadakova 1974, 1976, Tan and Iatrou 2001, Duran et al. 2003, 2008, Duran and Ocak 2005, Warwick and Al-Shehbaz 2006, Ünal et al. 2008, Table 2). In this study chromosome number 2n=12 for H. pisidica and 2n=14 for H. armena, H. kotschyi and H. thyrsoidea are added.
| Taxa | Chromosome number | Karyotype formulae | TCL (µm) | References |
|---|---|---|---|---|
| H. anatolica | 2n=14 | — | — | Duran et al. 2008 |
| H. armena | 2n=14 | — | — | Present study |
| H. aspera | 2n=14 | — | — | Duran et al. 2008 |
| H. balansae | 2n=12 | 8m+4sm | 36.75 | Ünal et al. 2008 |
| H. bicuspidata | 2n=14 | 6m+4sm+4ac | 21.59 | Duran et al. 2011 |
| H. bottae | 2n=12 | 8m+4ac | 23.13 | Duran et al. 2003 |
| H. kotschyi | 2n=14 | — | — | Present study |
| H. matronalis ssp. adzharica | 2n=14 | 6m+2sm+2ac+4t | 31.91 | Duran et al. 2003 |
| H. matronalis ssp. matronalis | 2n=14 | 6m+4ac+4t | 24.81 | Duran et al. 2003 |
| H. novakii | 2n=14 | 6m+2sm+2ac+4t | 23.02 | Duran et al. 2003 |
| H. özcelikii | 2n=12 | — | — | Duran et al. 2008 |
| H. pendula ssp. dirmilensis | 2n=12 | — | — | Duran et al. 2008 |
| H. pendula ssp. duralii | 2n=12 | 8m+4ac | 27.55 | Duran et al. 2003 |
| H. pisidica | 2n=12 | — | — | Present study |
| H. schischkinii | 2n=14 | — | — | Duran et al. 2008 |
| H. stellata | 2n=28 | 6m+2ac+6t | 18.42 | Duran et al. 2011 |
| H. syriaca var. quadrangula | 2n=14 | 6m+2sm+2ac+4t | 32.30 | Duran et al. 2003 |
| H. syriaca var. syriaca | 2n=14 | 6m+2sm+2ac+4t | 20.71 | Duran et al. 2003 |
| H. thrysoidea | 2n=14 | — | — | Present study |
| H. varolii | 2n=12 | 8m+4sm | 20.57 | Duran et al. 2003 |
TCL-the total chromosome length of the haploid complement; m-metacentric; sm-submetacentric; ac-acrosentric; t-telocentric
The number, size, and distribution of the satellites are used to characterize the differentiation of genera or related species (Ünal et al. 2008, Duran et al. 2011). H. pisidica is different from the others because of having a satellite. H. bicuspidata and H. syriaca, which reside in the genus, also have satellites (Ünal et al. 2008, Duran et al. 2011).
All studied species have 2n=14 chromosomes and are diploid, except H. pisidica (2n=12). This species is also different from the others because of having a satellite. Karyological characteristics in our study might contribute to the differentiation of Turkish Hesperis taxa.
I thank to the Scientific Investigation Project Coordinator of Selçuk University (Project No: 18401090) for their financial support. I also thank Prof. Dr. Kuddisi Ertuğrul and Prof. Dr. Tuna Uysal who let me work in his laboratory.
