Firenze University Press Caryologia www.fupress.com/caryologia International Journal of Cytology, Cytosystematics and Cytogenetics Chromosome counts and karyotype analysis of species of family Apocynaceae from Egypt Citation: S. Heneidak, E. Martin, F. Altinordu, A. Badr, H.E. Eroğlu (2019) Chromosome counts and karyotype analysis of species of family Apocyn- Samia Heneidak1,*, Esra Martin2, Fahim Altinordu2, Abdelfattah aceae from Egypt. Caryologia 72(4): Badr3, Halil Erhan Eroğlu4 69-78. doi: 10.13128/cayologia-192 1 Department of Botany, Faculty of Science, Suez University, Suez, Egypt Published: December 23, 2019 2 Department of Biotechnology, Faculty of Science, Necmettin Erbakan University, Konya, Turkey Copyright: © 2019 S. Heneidak, E. 3 Martin, F. Altinordu, A. Badr, H.E. Department of Botany and Microbiology, Faculty of Science, Helwan University, Egypt 4 Eroğlu. This is an open access, peer- Department of Biology, Faculty of Science and Art, Bozok University, Yozgat, Turkey reviewed article published by Firenze *Correspondence: [email protected] University Press (http://www.fupress. com/caryologia) and distributed under the terms of the Creative Commons Abstract. The chromosome counts of 13 species of family Apocynaceae in the flora of Attribution License, which permits Egypt have been reported; one species from subfamily Periplocoideae and the other unrestricted use, distribution, and 12 species from subfamily Asclepiadoideae. The chromosome numbers are 2n = 22 for reproduction in any medium, provided Periploca angustifolia, Glossonema boveanum, Pentatropis nivalis, Cynanchum acutum, the original author and source are Calotropis procera, Gomphocarpus sinaicus, Pergularia daemia and Pergularia tomen- credited. tosa; 2n = 24 for Leptadenia arborea and Solenostemma arghel; 2n = 22, 44 for Caudan- Data Availability Statement: All rel- thera edulis, Caudanthera sinaica and Desmidorchis acutangulus. The chromosome evant data are within the paper and its numbers and karyotype analyses were firstly reported in Leptadenia arborea (2n = 24). Supporting Information files. The polyploid nature was demonstrated by the prevalence of cells with 2n = 4x = 44 chromosomes in Caudanthera edulis, Caudanthera sinaica and Desmidorchis acutangu- Competing Interests: The Author(s) lus. The chromosomes are median and submedian as most species in the Apocynaceae. declare(s) no conflict of interest. The intrachromosomal asymmetry and interchromosomal asymmetry were estimated with MCA and CVCL values. In intrachromosomal asymmetry, Desmidorchis acutangulus is the most symmetrical karyotype, while Pergularia tomentosa is the most asymmet- rical karyotype. In interchromosomal asymmetry, Glossonema boveanum is the most symmetrical karyotype, while Cynanchum acutum is the most asymmetrical karyotype. Keywords. Apocynaceae, chromosome number, Egyptian flora, karyotype asymmetry. INTRODUCTION The family Apocynaceae comprises 366 genera and ca. 5100 species (Meve, 2002; Endress et al., 2014). This family is currently divided into five subfamilies; Periplocoideae, Asclepiadoideae, Apocynoideae, Rauvolfioideae, Secamonoideae (Endress and Bruyns, 2000; Endress et al., 2014). The major- ity of species represented in the Egyptian flora are classified in the two sub- families Periplocoideae and Asclepiadoideae. The subfamily Periplocoideae is a small group of species comprising only ca. 195 species in 33 genera (Henei- dak and Naidoo, 2015). On the other hand, Asclepiadoideae is the largest Caryologia. International Journal of Cytology, Cytosystematics and Cytogenetics 72(4): 69-78, 2019 ISSN 0008-7114 (print) | ISSN 2165-5391 (online) | DOI: 10.13128/cayologia-192 70 Samia Heneidak et al. subfamily of the Apocynaceae and contains about 3000 in Cynanchum acutum L. and Pergularia tomentosa L. species in 164 genera of five tribes. The tribes are divided (Fedorov, 1969). The deviating chromosome numbers, into 15 subtribes (Meve, 2002; Endress et al., 2014). i.e. 2n = 24 and x = 9 that were found previously and in Chromosome data have been constantly used for the present work were reported a deviating base chro- systematic purposes but chromosome number alone is mosome numbers in the genera Cynanchum, Microloma, not sufficient to exactly trace the evolutionary history and Sarcostemma (Albers et al. 1993). These authors gave of taxonomic groups. However, comparative karyotype an account of previously published deviating chromo- analysis of related species has traditionally been used to some numbers in the Asclepiadaceae. describe patterns and directions of chromosomal evolu- In subfamily Asclepiadoideae, the polyploidy rate tion within plant groups and to infer the evolutionary is approximately 6%. The polyploid species are mostly role of chromosomal changes in plant evolution (Steb- tetraploid (85%) with 2n = 44 and only a few are hexa- bins, 1971; Badr et al, 1997; 2009; Eroğlu et al., 2013; ploid with 2n = 66 (Albers and Meve, 2001). Albers Kamel et al. 2014). More detailed information about the (1983) reported the polyploid taxa in most of the genera karyotype has been found necessary in order to provide of tribe Ceropegieae. Albers and Meve (1991) observed diagnostics criteria for the systematics and phylogeny of that the proportion of polyploid cells in the meristems of plants (Altay et al., 2017). In fact, karyological features adventives roots is significantly higher than in the mer- are evaluated as important taxonomic characters only istems of primary and secondary roots in genera Duvalia when provide additional information and allow conclu- Haw., Hoodia Sweet ex Decne., Orbea Haw., Pectinaria sions about evolutionary events in the group of interest Haw., Stapelia, Trichocaulon N.E.Br. and Tridentea Haw. (Badr and Elkington, 1977; Peruzzi and Eroğlu, 2013). High ploidy levels were recorded in Tylophora anomala Survey of chromosome counts in the Apocynaceae N. E. Br.; for example the decatetraploid (2n = 132-154) in chromosome count reports, particularly the Index and the hexaploid (2n = 66) (Meve, 1999). to Plant Chromosome Numbers of the Missouri Botani- In Apocynaceae, the counting and measuring of cal Garden (http://www.tropicos.org/Project/IPCN) and small size of the chromosomes is difficult. The chromo- the Chromosome Counts Database (CCDB) (http://ccdb. somes form a graded series with only very slight dif- tau.ac.il) which is a community resource of plant chro- ferences in morphology (Albers, 1983). Within a single mosome numbers (New Phytol. 206(1): 19-26) as well karyotype the chromosomes are comparatively similar as the old counts reported in Federov (1969) as well as in size. The heterogeneous karyotypes were only found the chromosome count reports that was frequenty pub- where chromosome sizes varied considerably in the sub- lished in the Journal Taxon indicated thatseveral authors families Periplocoideae, Asclepiadoideae and Secamo- have reported chromosome numbers of many species of noide (Albers and Meve, 2001). the Apocynaceae. Several authors have reported chro- In the present study, 13 species of the family Apo- mosome numbers of many species of the Apocynaceae cynaceae were investigated karyologically to determine (Francini, 1927; Mitra and Datta, 1967; Fedorov, 1969; the chromosome numbers and to compare with earlier Arrigoni and Mori, 1976; Albers and Delfs, 1983; Albers results. In addition, the karyotype of the examined spe- and Austmann, 1987; Khatoon and Ali 1993; Liede 1996; cies growing in Egypt has been analysed using a number Albers et al., 1993; Albers and Meve, 2001; Kamel et al., of chromosome characterizing parameters such as varai- 2014). These studies showed that the family is karyologi- tions in length, arm ration and centromeric asymmetry cally almost entirely homogenous, especially subfamilies indices in order to gather more information that might Asclepiadoideae and Periplocoideae, with nearly 96% of help a better understanding of the taxonomic treatment the taxa investigated so far having chromosome comple- of the species of Apocynaceae in the Egyptian flora. ments in multiples of a basic number of x = 11, with a few deviating numbers. Deviating chromosome numbers were reported with MATERIALS AND METHODS 2n = 18, 24 in Funastrum clausum (Jacq.) Schulr. and Funastrum cynanchoides (Decne.) Schulr. (tribe Ascle- Plant materials piadeae) (Albers et al., 1993), 2n = 20 in Microloma inca- num Decne. Microloma calycinum E. Mey., Microloma Seeds of 13 species of Apocynaceae were collected sagittatum (L.) R. Br. and Microloma tenuifolium (L.) from mature flowers from sites in their natural habitats K. Schum. (tribe Asclepiadeae) (Albers et al., 1993) and as given in Table 1 and mapped as in Figure 1. Vouch- 2n = 24 in Periploca graeca L. (subfamily Periplocoide- er specimens of the examined species are kept at Suez ae) (Pesci, 1971). In literature, x = 9 was only reported University Herbarium. In the two succulent species (Caudanthera edulis and Desmidorchis acutangulus), Chromosome counts and karyotype analysis of species of family Apocynaceae from Egypt 71 Table 1. List of species examined and the localities from which plants used for chromosome counts were collected and date of collection. Taxa Date Locality 1. Periploca angustifolia Labillardiere 12.06.2009 El-Salûm: Wadi Salufa, 31º37’24’’N–25º09’00’’ E, Morsy et al. s.n. Gebel Elba: Wadi Yahameib, 22º25’18’’N–36º18’33’’E, Morsy et 2. Caudanthera edulis (Edgew) Meve & Liede 27.01.2009 al. s.n. 3. Caudanthera sinaica (Decne.) Plowes 10.05.2009 North Sinai: