Arch. BioL Sci., Belgrade, 54 (1-2), 19P-20P, 2002
B CHROMOSOMES IN WILD GARLIC, ALLIUM URSINUM. M. Vujosevic and Jelena Blagojevic,
Department of Genetics, Institute for Biological Research "SiniSa Stankovic", 11060, Belgrade, Yugoslavia
UDC 574.312.32: 582.572.285
smaller than any member of the standard chromosome complement (1.8 p versus 9 u for the smallest chromosome of normal karyotype) and were totally heterochromatic. They were
morphologically similar to B chromosomes found in Allium
schoenoprasum (S t eve n sand B 0 u g 0 u r d 1994).
Although chromosomes of A. ursinum were studied repeatedly
from the time when they were counted for the first time (L evan 1931), according to our survey of literature this is the ftrst
time that the presence of Bs is scored in this species. This
points that further studies of populations of this species are
necessary.
The B chromosomes (Bs), which are supernumerary to
the standard chromosome complement, are characterized
by dispensable nature. This is the only property shared by all
of them, and it enables Bs to follow their own evolutionary
pathway (C a mac h 0 et al. 2000). B chromosomes are one
of many causes of numerical chromosome polymorphisms in
plants, animals and fungi. More than 1300 plants species possess Bs. In the family Liliaceae order Allium is characterized by
a frequent occurrence of Bs. B chromosomes are found in 27
species of Allium (J 0 n e sand R e e s 1982) including polyploid species.
The plants used in this study were collected from a natural population of wild garlic, Allium ursinum, from Kosutnjak
(Belgrade, Yugoslavia). Karyotypes were prepared from root
tips treated with 0.03% (w/v) colchicine solution for 5 h, fixed
in 1:3 (v/v) acetic-acid-alcohol overnight, hydrolyzed in IN HCI
at 60°C for 12 min, stained in aceto-orcein, and squashed.
Chromosomes were measured using software Analyst (M a 1k 0 v et al. 1997).
Normal complement of Allium ursinuni is composed of
seven pairs of large meta and submetacentric chromosomes
(L e van 1931). All chromosome counts, obtained from the
samples, were the same 2n=14, but in some plants one small
additional chromosome was present (Fig. 1). All Bs were much
Acknowledgement - This study was supported by the Ministry
for Science, Technology and Development of the Republic of
Serbia, Grant No. 1693
References: Camacho, J. P. M., Sharbel, T. F. and Beukeboom,
L.W. (2000). Philosoph Transactions of the Royal Soc. 355,
163-178. - Jones, R. N. and Rees, H. (1982). B Chromosomes.
New York: Academic Press. - Levan, A. (1931). Hereditas 15,
347-356. - Malkov, S., Jovanovic, A. and Vujosevic, M. (1997).
Cytogenetics and Cell Genetics 77, 1-2, 61. - Stevens and
Bougourd (1994). Biological Journal of the Linnean Society 52,
357-363.
Figure 1 Metaphase in Allium ursinum with B chromosome arrowed
19P