In this study, we examine the morphology, mitotic stability, meiotic behavior and the composition of heterochromatin of B chromosomes in Cestrum intermedium and C. strigilatum. The results showed that B chromosome number shows intraindividual variation in the root meristem, which seems to lead to a slight rate of B elimination in this somatic tissue. B chromosomes in both species were similar in size and shape, but differed with regard to the type, size and distribution of heterochromatin. Possible evolutionary pathways for B chromosome origin in Cestrum are discussed.   

1.
Berg C, Greilhuber J: Cold-sensitive chromosome regions and heterochromatin in Cestrum (Solanaceae): C. strigilatum, C. fasciculatum, and C. elegans. Plant Syst Evol 185:133–151 (1993a).
2.
Berg C, Greilhuber J: Cold-sensitive regions and heterochromatin in Cestrum aurantiacum (Solanaceae). Plant Syst Evol 185:259–273 (1993b).
3.
Beukeboom LW: Bewildering Bs: an impression of the 1st B-chromosome conference. Heredity 73:328–336 (1994).
4.
Bold HC: Bristol’s solution and medium. (1949). Available at: http://www.pai.utexas.edu/research/utex/media/bristol.html.
5.
Camacho JPM, Sharbel TF, Beukeboom LW: B chromosome evolution. Phil Trans R Soc Lond B 355:163–178 (2000).
6.
Cheng YM, Lin BY: Cloning and characterization of maize B chromosome sequences derived from microdissection. Genetics 164:299–310 (2003).
7.
Cuadrado A, Jouve N: Mapping and organization of highly-repeated DNA sequences by means of simultaneous and sequential FISH and C-banding in 6x-Triticale. Chromosome Res 2:331–338 (1994a).
8.
Cuadrado A, Jouve N: Highly repetitive sequences in B chromosomes of Secale cereale revealed by fluorescence in situ hybridization. Genome 37:709–712 (1994b).
9.
Dhar MK, Friebe B, Koul AK, Gill BS: Origin of an apparent B chromosome by mutation, chromosome fragmentation and specific DNA sequence amplification. Chromosoma 111:332–340 (2002).
10.
Franks TK, Houben A, Leach CR, Timmis JN: The molecular organisation of a B chromosome tandem repeat sequence from Brachycome dichromosomatica. Chromosoma 105:223–230 (1996).
11.
Guerra M: Patterns of heterochromatin distribution in plant chromosomes. Gen Mol Biology 23:1029–1041 (2000).
12.
Hossain MA, Bauchan GR: Identification of B chromosomes using Giemsa banding in Medicago. J Heredity 90:428–429 (1999).
13.
Houben A, Leach CR, Verlin D, Rofe R, Timmis JN: A repetitive DNA sequence common to the different B chromosomes of the genus Brachycome. Chromosoma 106:513–519 (1997).
14.
Houben A, Thompson N, Ahne R, Leach CR, Verlin D, Timmis JN: A monophyletic origin of the B chromosomes of Brachycome dichromosomatica (Asteraceae). Plant Syst Evol 219:127–135 (1999).
15.
Puertas MJ: Nature and evolution of B chromosomes in plants: A non-coding but information-rich part of plant genomes. Cytogenet Genome Res 96:198–205 (2002).
16.
Qi ZX, Zeng H, Li XL, Chen CB, Song WQ, Chen RY: The molecular characterization of maize B chromosome specific AFLPs. Cell Res 12:63–68 (2002).
17.
Schwarzacher TP, Ambros P, Schweizer D: Application of Giemsa banding to orchid karyotype analysis. Plant Syst Evol 134:293–297 (1980).
18.
Smith LB, Downs RJ: Solanáceas, in Reitz PR (ed): Flora Ilustrada Catarinense. Part 1, pp 1–321 (Biblioteca Superior de Cultura, Itajaí 1966).
19.
Stark EA, Connerton I, Bennett ST, Barnes SR, Parker JS, Forster JW: Molecular analysis of the structure of the maize B-chromosome. Chromosome Res 4:15–23 (1996).
20.
Sýkorová E, Yoong Lim K, Fajkus J, Leitch AR: The signature of the Cestrum genome suggests an evolutionary response to the loss of (TTTAGGG)n telomeres. Chromosoma 112:164–172 (2003).
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