Open AccessSatellited Chromosomes, Nucleolus Organizer Regions and Nucleoli of Brassica campestris L., B. nigra (L.) Koch, and Sinapis arvensis L.
Author(s) -
Cheng B. F.,
Heneen W. K.
Publication year - 1995
Publication title -
hereditas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 50
eISSN - 1601-5223
pISSN - 0018-0661
DOI - 10.1111/j.1601-5223.1995.00113.x
Subject(s) - nucleolus , biology , sinapis , nucleolus organizer region , brassica , genetics , botany , cytoplasm
Giemsa staining was used to characterize the satellited chromosomes, and silver staining, to detect nucleolus organizer regions and nucleoli in Brassica campestris (genome: AA, 2n = 20), B. nigra (BB, 2n = 16) and Sinapis arvensis (SS, 2n = 18). B. campestris had one pair of satellited chromosomes, while B. nigra had three pairs. S. arvensis had five distinct satellited chromosomes and a sixth chromosome with a faint satellite. Silver‐stained nucleolus organizer regions (Ag‐NORs) were localized at the secondary constrictions of the satellited chromosomes. Two Ag‐NORs and a maximum number of two nucleoli were revealed in B. campestris , Heteromorphism for size of Ag‐NORs and nucleoli was observed in one accession of B. campestris. In B. nigra , six Ag‐NORs and six nucleoli were observed at early and late telophase, respectively. In S. arvensis , six Ag‐NORs and six nucleoli were revealed. Size differences were noticed within and between pairs of Ag‐NORs. The presence of three pairs of active NORs in B. nigra and S. arvensis is an additional support for the hypothesis of a basic number of ×= 3 in the Brassiceae.