The Giemsa C-Banded Karyotype of Cvithopsis Delileana (Poaceae
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The Giemsa C-banded karyotype of Crithopsis delileana (Poaceae: Triticeae) Linde-Laursen, Ib; Frederiksen, Signe; Seberg, Ole Published in: Hereditas Publication date: 1999 Document version Publisher's PDF, also known as Version of record Citation for published version (APA): Linde-Laursen, I., Frederiksen, S., & Seberg, O. (1999). The Giemsa C-banded karyotype of Crithopsis delileana (Poaceae: Triticeae). Hereditas, 130(1), 51-55. Download date: 29. sep.. 2021 Hereditas 130: 51 -55 (1999) The Giemsa C-banded karyotype of Cvithopsis delileana (Poaceae; Triticeae) IB LINDE-LAURSEN', SIGNE FREDERIKSEN2 and OLE SEBERG2 Plant Biology and Biogeochemistry Department, Rise National Laboratory, Roskilde, Denmark Botanical Institute, University of Copenhagen, Copenhagen, Denmark Linde-Laursen, I., Frederiksen, S. and Seberg, 0. 1999. The Giemsa C-banded karyotype of Crithopsis delileunu (Poaceae; Triticeae).-Hereditrrs 130: 51-55. Lund, Sweden. ISSN 0018-0661. Received November 5, 1998. Accepted January 12. 1999 Three populations of Crithopsis delileunu had similar karyotypes. They included 14 large chromosomes; five pairs of metacentrics, one pair of submetacentrics, and one pair of metacentric SAT-chromosomes with rather small satellites. The karyotypes of two populations were investigated in detail through application of Giemsa C-banding, Giemsa N-banding and AgN0,-staining to meta- and interphases. The C-banding patterns included a few small to very small, mainly centromeric or telomeric bands. The chromosomes of the two populations were differentiated by banding pattern polymorphism. Banding patterns identified homologous and discriminated among non-homologous chromosomes within the same population. The scarcity of diagnostic bands prevented identification of homologous chromosomes between populations beyond the level obtained from morphology, i.e., of submetdcentrics and SAT chromosomes. N-banding produced no or few weak bands. Silver nitrate staining produced two NORs and two nucleoli corresponding to the number of SAT-chromosomes. The data give some support to a hypothesis of a closer relationship between the genera Critlzopsis and Tueniutherum, than between either of these and the genera Psuthyrostuchys and Hordeum. Ib Linde-Loursen, Botunicul Section, Deportment of Ecology, The Royul Veteririury and Agriculturul Univer.yity, Rolighedsvej 21, DK- 1958 Frederiksberg C (Copenhugen), Dwnnurk Signe Frederiksen and Ole Seberg, Botanical Institute, Uniuersity of Copenhugen, Gothersgude 140, DK- 1123 Copenhugen K, Denmurk The annual species C. delileanu (SCHULTES) RO- on this basis, to see whether or not the data confer SHEV. is the only member of the genus Crithopsis added substance to the hypothesised relationships JAUB. et SPACH. (Poaceae; Triticeae). It is dis- with the genera Taeniatherum, Psathyrostuchys and tributed from western Afghanistan and Baluchistan Hordeum as indicated by morphology. We have pre- to Morocco (FREDERIKSEN1993). According to viously used the techniques successfully with the Love (1984) it carries the K genome. SAKAMOTOand chromosomes of species of these genera (LINDE- MURAMATSU(1965) were the first to report 2n = 14. LAURSEN198 1, 1984; LINDE-LAURSENand BOTH- This number was confirmed by SAKAMOTO(1973) in MER 1984a,b, 1986; LINDE-LAURSEN and material collected in Syria and by FREDERIKSENFREDERIKSEN 1989; BADEN et al. 1990; LINDE- (1993) in populations from Iraq, from the island of LAURSENand BADEN 1994a,b; LINDE-LAURSENet Crete, Greece, and from Palestine. Both authors re- al. 1995). ported that the chromosomes were meta- or submeta- centric. FREDERIKSEN(1993) observed that one pair carried rather short satellites. Traditionally, the MATERIAL AND METHODS diploid genera Crithopsis, Taeniatherum NEVSKI Plants. - Three populations of C. delileanu previ- and Psathyrostachys NEVSKI, and Hordeum L. have ously studied by SAKAMOTO(1 973) and FREDERIK- been considered rather closely related (e.g., BOTHMER SEN (1993) were used (Table 1). For their origins, see et al. 1995), sharing a similar spike morphology (2-3 the latter. Seeds were germinated and plants grown as spikelets per node). Recent phylogenetic analyses described in LINDE-LAURSEN(1975) and LINDE- based on morphology support a close relationship as LAURSENet al. (1980). Only the populations H 5558 all four genera are included within the same, albeit from Iraq and H 5562 from the island of Crete, not fully resolved clade (FREDERIKSENand SEBERG Greece, were studied in greater detail. 1992 and unpubl.). Cytology. - Giemsa C-banding and Giemsa N-band- The aim of the present paper was to characterize ing were performed on meristematic root-tip cells the chromosome complement of C. delileanu in detail following LINDE-LAURSENet al. (1980) and LINDE- through the application of Giemsa C-banding, LAURSENand BOTHMER (1984a), respectively. Silver Giemsa N-banding and silver nitrate staining, and, nitrate staining of somatic metaphases and inter- 52 I. Linde-Laursen et al. Hereditas 130 (1999) phases to demonstrate nucleolus organizer regions some pair (Fig. 1 and 2). The rather small satellites (NORs) and nucleoli, respectively, was done accord- were carried on the subtending short arms of the ing to LINDE-LAURSEN(1984). Most observations of latter pair. Only the two last-mentioned chromosome banding patterns were performed on metaphases pairs could be identified reliably by morphology derived from root-tips of germinating seeds as these within and between populations establishing homol- generally had bands of a higher quality than ogy. The morphological differences between the metaphases from root-tips of plants growing in pots metacentric chromosomes were insufficient for safe in the greenhouse. identification. Idiogrums. - The construction of idiograms followed The C-banding patterns were characterized by the LINDE-LAURSENet al. (1980). The chromosomes as presence of two or three small or very small bands measured in one cell of each population having 14 per chromosome arm, mostly located at centromeric well-spread chromosomes identifiable by their C- and telomeric positions (Fig. 1 and 2). A few bands, banding patterns were grouped into metacentrics, generally located at distal positions were intercalary. submetacentrics and satellited (SAT-) chromosomes Bands were present at both sides of the nucleolar (cf. LEVANet al. 1965). Within the group of metacen- constrictions with the larger ones in the short arms. trics, the chromosomes were arranged by decreasing The banding patterns of populations H 5558 and H length. C-banding patterns were primarily prepared 5562 were polymorphic. Within populations the vari- from observations on 14 well-banded chromosomes ation in banding patterns was sufficient for identify- of four cells collected from two plants of either ing the homologous chromosomes of each of the population. The content of constitutive heterochro- seven pairs and differentiating between non-ho- matin was estimated according to LINDE-LAURSENet mologous chromosomes. Between populations, the al. (1980). scarcity of diagnostic bands coupled with the banding pattern polymorphism prevented a safe identification of chromosome homology beyond the level already RESULTS obtained by observation of the non-banded chromo- somes, i.e., of submetacentric and SAT-chromo- The three accessions of C. delileanu had 2n = 14 somes. The identical banding patterns of the two (Table 1; Fig. 1) in accordance with previous counts homologues of each chromosome pair agrees with the (SAKAMOTOand MURAMATSU1965; SAKAMOTO generally inbreeding reproductive system of the spe- 1973; Frederiksen 1993). The chromosomes were cies (FREDERIKSEN1993). large. The mean lengths of the chromosomes of pop- Giemsa-stained interphase nuclei presented small ulations H 5558 and H 5562 were 10.5 and 13.7 pm, chromocentres in a number corresponding with that respectively (Table I). The difference in mean length of the more conspicuous C-bands. The amount of is due to differences in chromosome contraction as constitutive heterochromatin that ranged from 3.5 to the quotient longest/shortest chromosome of 1.5 is 5.3 per cent of total chromosome length was low in the same (Table 1). Their karyotypes were similar and accordance with the presence of few and small C- corresponded overall with figures of metaphases pub- bands only (Table 1). lished earlier (SAKAMOTO1973; FREDERIKSEN1993). N-banding produced no or few weakly developed They included five pairs of metacentrics, one pair of bands in the chromosomes at the same positions as submetacentrics, and one metacentric SAT-chromo- C-bands. Table I. Chromosome number, maximum number of submetacentrics, SA T-chromosomes, NORs and nucleoli, mean chromosome length, quotient longest /shortest chromosome, and amount of constitutive heterochromatin (Per cent) oj the Crithopsis delileunu populations studied Pop. No. 2n No. observed (max.) Mean chr. Longest/ Const. het. length (pm)’ shortest chr. chrom. (Yn) Submeta- SAT-chr. NORs Nucleoli centrics H 5558 14 2 2 2 10.5 (8.7-13.3) 1.5 5.3 H 5562 14 2 2 2 2 13.7 (11.0-16.6) 1.5 3.5 H 5571 14 2 2 2 T. c.-m.’ 14 2 2 2 2 12.8 (9.6-16.8) 1.3 4.6 I Tuenicrtherurn cuput-medusae. Cf. Table 1 in LINDE-LAURSENand FREDERIKSEN (1989). Average of observations in three diploid plants Range in brackets Hereditas 130 (1 999) C-bunded kuryotvpe of Crithopsis delileunu 53 In contrast to the comparatively minor differences in chromosome morphology that distinguish the karyotypes of C. delileunu and T. cuput-medusue, the karyotypes