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Turczaninowia 24, 1: 83-88 (2021) DOI: 10.14258/turczaninowia.24.1.10 http://turczaninowia.asu.ru
ISSN 1560-7259 (print edition)
TURCZANINOWIA
ISSN 1560-7267 (online edition)
УДК 582.998.2:576.316(55)
Karyotype analysis and chromosome number for two Cirsium taxa (Asteraceae) in Iran
Z. Babaee1- 3, M. Norouzi2 6, S. Mosaferi1- 4*, M. Keshavarzi1 5
1 Department of Plant Sciences, Faculty of Biological Sciences, Alzahra University, North Sheikh Bahaee St., Deh-e Vanak, Tehran, Iran
2 Department of Horticulture, College of Aburaihan, University of Tehran, Tehran, Iran
3E-mail: zohrehbabaee74@gmail.com; ORCID iD: https://orcid.org/0000-0002-5277-6260
4 E-mail: s.mosaferi@alzahra.ac.ir; ORCID iD: https://orcid.org/0000-0003-0501-6637
5E-mail: m.keshavarzi@alzahra.ac.ir; ORCID iD: https://orcid.org/0000-0003-3032-9408
6E-mail: mnorouzi91@ut.acir; ORCID iD: https://orcid.org/0000-0003-1855-7600
Keywords: Asteraceae, B-chromosome, Cirsium, karyology, mitotic study.
Summary. Cirsium Mill. contains more than 250 species in the world mainly distributed in the Northern hemisphere. Different chromosome numbers with different ploidy levels were reported in this genus. In this study, karyotype details and chromosome numbers were established for two Cirsium taxa in Iran. C. ciliatum subsp. szovitsii and C. echinus had the mitotic chromosome numbers of 2n = 2x = 34. Karyotype analyses showed that chromosomes were generally metacentric and sub-metacentric. In C. echinus, Lowshan population had the longest chromosome (19.10 ^m) and Heyran Canyon population (4.73 ^m) the shortest one while in C. ciliatum, the longest chromosome was observed in Urmia to Salmas population (14.67 ^m) and the shortest one (4.71 ^m) in Doshanlu population. Total haploid chromosome length ranged from 275.29 to 376.42 ^m in populations studied. Both taxa were grouped in 2B class. B-chromosomes were recorded for two taxa studied too. Chromosome type, mitotic chromosome numbers and occurrence of B-chromosomes were in agreement with previous results (Albers, Pröbsting, 1998; Lövkvist, Hultgärd, 1999; Yüksel et al., 2013; Yildiz et al., 2016).
Анализ кариотипа и число хромосом двух видов Cirsium (Asteraceae) флоры Ирана
З. Бабаи1, М. Норузи2, C. Мосафери1, М. Кешаварзи1
1 Кафедра ботаники, биологический факультет, Университет Аль-Захра, ул. Северного Шейха Бахаи,
Дех-э Ванак, г. Тегеран, 1993891176, Иран
2 Кафедра садоводства, Колледж Абураихана, Тегеранский университет, 16-я улица Азара, площадь Энгелаб, г. Тегеран, 1417466191, Иран
Ключевые слова: B-хромосома, кариология, митотическое исследование, Asteraceae, Cirsium.
Аннотация. В мировой флоре род Cirsium Mill. содержит более 250 видов, в основном распространенных в Северном полушарии. Для видов этого рода характерно варьирование числа хромосом и кариотипы с разным уровнем плоидности. Для Cirsium ciliatum subsp. szovitsii и C. echinus, произрастающих в Иране, установлено
* Corresponding author
Поступило в редакцию 03.07.2020 Принято к публикации 09.03.2021
Submitted 03.07.2020 Accepted 09.03.2021
митотическое число хромосом 2n = 2x = 34. Кариотип обоих видов представлен в основном метацентрически-ми и субметацентрическими хромосомами. У C. echinus наибольшая длина хромосомы (19,10 мкм) отмечена в популяция из окр. г. Ловшан, наименьшая (4,73 мкм) - в популяции из каньона Хейран. Для C. ciliatum эти значения составили, соответственно, 14,67 (популяция из окг. г. Сельмас) и 4,71 мкм (популяция из окр. дер. Дошанлу). В изученных популяциях длина гаплоидных хромосом варьирует от 275,29 до 376,42 мкм. Оба таксона отнесены к классу 2В, у обоих зарегистрированы В-хромосомы. Выявленные особенности и значения (тип хромосом, число митотических хромосом и встречаемость B-хромосом) согласуются с результатами предыдущих исследований (Albers, Pröbsting, 1998; Lövkvist, Hultgärd, 1999; Yüksel et al., 2013; Yildiz et al., 2016).
Introduction
Cirsium Mill. (Asteraceae) with more than 250 taxa is a large genus that is distributed in holarctic with several diversification centers (Zomlefer, 1994). These taxa show high diversity from the northern Mediterranean area over to Caucasus (Haffner, Hellwig, 1999). Cirsium species are classified in five sections, as Pseudepitrachys Petrak, Echenias (Cass.) Petrak, Cephalonoplos (Neck.) DC., Cirsium and Epitrachys DC. in Iran (Petrak, 1979).
The first chromosome counting for Cirsium dated back to Aishima (1934) as x = 17 and two ploidy levels (diploid and tetraploid) were defined. Frankton and Moor (1963) proposed x = 17 for the elements of tribe Cardueae. The presence of aneuploidy in Cirsium of the new world was recorded by Ownbey and Olson (1969). Some of the cytological studies in this genus related to the definition between Cirsium and Carduus L., based on the basic chromosome number (Frankton, Moore, 1961; Hedberg I., Hedberg O., 1977). Some researches illustrated that the lower chromosome number was correlated with the more assymetrical chromosomes. Bures et al. (2004) studied the chromosomes of 17 Cirsium species and stated that B-chromosome presence had significant effect on the increase or decrease of chiasmata frequency and the obtained genetic variation in gametes.
The cytological studies of Cirsium in Turkey showed different chromosome numbers of 2n =
32, 34, 60 and 68 (Melahat et al., 2008). The most common chromosome number was 2n = 34 (diploids) and 2n = 68 (tetraploids). Nourouzi et al. (2010) studied meiosis in 17 Cirsium species of Iran. They recorded 0-2 B-chromosomes. Meiotic abnormalities were recorded in some species. Yuksel et al. (2013) studied the karyotype properties of 10 Cirsium species of sect. Epitrachys in Turkey.
Despite much attention to the taxonomy and morphology of Cirsium species, karyological records for the genus are scarce. Karyology of Iranian Cirsium species has been studied to clarify their taxonomy and make contributions to other multidisciplinary studies on the genus (Nouroozi et al., 2010, 2011; Sheidai et al., 2012). In this study karyotype analyses and chromosome numbers of two Cirsium taxa are presented.
Materials and Methods
Karyotype study was done on two Cirsium taxa: C. echinus (M. Bieb.) Hand.-Mazz. and C. ciliatum subsp. szovitsii (K. Koch) Petr. To achieve the chromosome numbers oftaxa studied, six accessions including four accessions of C. echinus and two accessions of C. ciliatum subsp. szovitsii were gathered from nature (Table 1). Cypselas were sterilized by 50 % H2O2 for 10-15 min., washed by sterile water for 5 min., then put in Petri dishes and kept at room temperature until germination. Growing root tips with 1-2 cm in length were pretreated with
Voucher details of Cirsium taxons studied
Table 1
Locality, collector and voucher number
Pop no.
Taxon
Gilan prov., Asalem to Khalkhal, Asbdavani village, 2000 m, Norouzi, Babaee (ALUH 910)
Gilan prov., Rudbar, Lowshan, 353 m, Norouzi, Babaee (ALUH 912) Gilan prov., Astara, Heyran Canyon, 860 m, Norouzi, Babaee (ALUH 908) East Azerbaijan prov., Kiamaky Canyon, 1999 m, Norouzi, Babaee (ALUH 909) Ardebil prov., Meshgin Shahr, Doshanlu, 1170 m, Norouzi, Babaee (ALUH 902)
West Azerbaijan prov., Urmia to Salmas, 1282 m, Norouzi, Babaee (ALUH 904)
C. echinus (M. Bieb.) Hand.-Mazz.
C. ciliatum subsp. szovitsii (K. Koch) Petr.
6
0.002 m 8-hydroxyquinoline for 3 hours at 4 °C (7-9 AM). Then they were fixed with Carnoy solution (1 :
3 glacial acetic acid/absolute ethanol) for 24 h. at
4 °C. Materials were hydrolyzed in 1 N HCl for 20 min. at 60 °C bath and washed by sterile water.
Meristematic regions were stained with 1 % aqueous Aceto-orcein for 60 min. at 60 °C bath and squashed on slides with one drop of 45 % glacial acetic acid. At least 5-10 well prepared metaphase plates for each population were photographed with Olympus BX-51 microscope and measured by IdeoKar 1.0 software.
The chromosomes were identified based on Levan et al. (1964). Karyotype asymmetry indices as variation of chromosome length (CVCL) (Paszko, 2006), coefficient variation of centromeric index (CVCI), mean centromeric asymmetry (MCA) and mean centromeric index (MCI) (Paszko, 2006) and intra and inter-chromosomal asymmetry (A1 and A2 respectively) (Zarco, 1986) were determined.
Results
In present study, karyotype analyses were done for two taxa (C. echinus and C. ciliatum subsp. szovitsii). Chromosome counts were 2n = 2x = 34 with the basic chromosome number n = 17 (Table 2). Based on Stebbins symmetry class, populations of two taxa studied were grouped in 2B class. The taxa studied differed in karyotype formula. They had metacentric
(m) and sub-metacentric (sm) chromosomes (Figs 1, 2). In studied populations of C. echinus, the longest chromosome was observed in Lowshan population and the smallest in Heyran Canyon one. Among populations studied of C. ciliatum subsp. szovitsii, the longest chromosome (14.67 pm) was observed in Urmia to Salmas population and the shortest one (4.71 pm) was observed in Doshanlu population.
Lowshan population of C. echinus had the longest chromosome length (19.10 pm) and Doshanlu population of C. ciliatum subsp. szovitsii had the shortest (4.71 pm). Doshanlu population of C. ciliatum subsp. szovitsii had the shortest total haploid length (275.29 pm) while Heyran canyon population of C. echinus had the longest (376.42 pm). A1 index varied from 0.28 in Doshanlu population of C. ciliatum subsp. szovitsii to 0.36 in Lowshan population of C. echinus. A2 index ranged from 0.27 (Doshanlu population of C. ciliatum subsp. szovitsii) to 0.40 (Kiamaky Canyon population of C. echinus). The highest value of coefficient variation of centromeric index (CVa) was observed in Urmia to Salmas population of C. ciliatum subsp. szovitsii (18.35) and the lowest value of CVCI was observed in Lowshan population of C. echinus (14.91). Kiamaky Canyon population of C. echinus showed the highest value of coefficient variation of chromosome length (CVCL) (39.82) and Doshanlu population of C. ciliatum subsp. szovitsii showed the lowest (26.77).
Table 2
Summary of karyotype features in Cirsium populations studied
KF ST TF% MCI MCA CVCL CVCI THL L/S Range S-L A2 A1 Pop no. Taxon
12m + 5sm 2B 39.53 0.40 20.86 28.52 14.95 355.81 2.25 6.9515.62 0.29 0.33 1
14m + 3sm 2B 38.32 0.38 23.20 29.65 14.91 328.71 2.76 6.9219.10 0.30 0.36 2 C.
12m + 5sm 2B 39.86 0.39 21.26 32.54 17.77 376.42 3.82 4.7318.06 0.33 0.33 3 echinus
13m + 4sm 2B 39.60 0.40 20.41 39.82 17.58 322.03 2.86 5.4615.61 0.40 0.32 4
12m + 5sm 2B 41.39 0.41 17.88 26.77 16.90 275.29 2.72 4.7112.83 0.27 0.28 5 C. ciliatum
12m + 5sm 2B 40.21 0.40 19.32 28.36 18.35 304.40 2.80 5.2514.67 0.28 0.30 6 subsp. szovitsii
Abbreviations: A1: intrachromosomal asymmetry, A2: interchromosomal asymmetry, S: size of the shortest chromosome pair, L: size of the longest chromosome pair, THL: total haploid length, CVCI: coefficient variation of centromeric index, CVCL: variation of chromosome length, MCA: mean centromeric asymmetry, M : mean centromeric index, TF: total form percentage, ST: Stebbins' symmetry class, KF: karyotype formulae.
Lowshan population of C. echinus was characterized by the lowest value of mean centro-
meric index (MCI) (0.38) and total form percentage (TF %) (38.32) while Doshanlu population of
C. ciliatum subsp. szovitsii was characterized by the lowest (17.88) value of mean centromeric the highest value of MCI (0.41) and TF % (41.39). asymmetry (MCA) vice versa. These two population had the highest (23.20) and
a j£ , r. f * i' '-» < \V - , -: f> " b v A \ H V ;
c /r Ai . # v 1 4 y t r" !il / ' , Mi A M ~ d 1 S/ »
e ¿x- Mi^V PI r f •¿Ay 1
Fig. 1. Somatic chromosomes of Cirsium taxa studied: a - Asbdavani village population; b - Lowshan population; c - Heyran Canyon population; d - Kiamaky Canyon population in C. echinus; e - Doshanlu population; f - Urmia to Salmas population of C. ciliatum subsp. szovitsii (scale bar: 50 micrometers; Arrows show the B-chromosome).
Fig. 2. Haploid ideograms of Cirsium taxa studied: a - Asbdavani village population; b - Lowshan population; c -Heyran Canyon population; d - Kiamaky Canyon population of C. echinus; e - Doshanlu population; f - Urmia to Salmas population of C. ciliatum subsp. szovitsii.
Discussion
Obtained chromosome counts for C. ciliatum subsp. szovitsii and C. echinus (2n = 2x = 34) were in concordant with the previous findings of Tonian (1981, 1982), Yuksel et al. (2013) and Yildiz et al. (2016). Most Cirsium species are diploid (2n = 34) (Ownbey et al., 1975). In Armenia, chromosome count for C. ciliatum was recorded as 2n = 4x = 68 (Tonian, 1982) while in Turkey Melahat et al. (2008) recorded 2n = 2x = 34. Nouroozi et al. (2010) recorded miotic chromosome number in 17 species of Cirsium with chromosome numbers of 2n = 2x = 34 and 2n = 4x = 68. There is no report on mitotic number of Cirsium species in Iran.
In present study, chromosome length varies between 4.71 to 19.10 micrometer. The ratio of longest to shortest chromosome varies between 2.25 to 3.82. Yuksel et al. (2013) analyzed the karyotype features of ten Cirsium species of sect. Epitrachys in Turkey. They stated that generally the chromosome number for these species is 2n = 2x = 34 and the chromosome length is of taxonomic use to separate species.
Karyotype analyses showed that Cirsium species are of m and sm types that is in agreement with Yüksel et al. (2013). Based on karyotype asymmetry parameters, Doshanlu population of C. ciliatum subsp. szovitsii had higher value of TF % and represented more symmetrical karyotype. Lowshan population of C. echinus with the highest value of A1 index showed more asymmetrical karyotype.
In present study, B-chromosome are recorded for the two taxa studied for the first time in Iran. B-chromosomes were 0 to 2 in species studied, rounded and very smaller than A-chromosomes. B-chromosomes were recorded for some Cirsium species as C. acaule (L.) Scop. (0-2) (Lövkvist, Hultgârd, 1999), C. arvense (L.) Scop. (0-1) (Lövkvist, Hultgârd, 1999) and C. oleraceum Scop. (0-2) (Albers, Pröbsting, 1998). B-chromosomes are present in both diploid and tetraploid Cirsium species so it seems that there is no advantage for their occurrence due to ploidy levels. Further studies of the karyotype properties will have implications in the systematics of the genus Cirsium in Iran.
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