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Karyotype Analysis in Lycoris longituba Y. Hsu et Fan


A karyotypic analysis of Lycoris longituba Y. Hsu et Fan was carried
out. The voucher specimen, Z. G. Mao 10501, is preserved in the Herbarium of Hangchow
Botanical Garden. The chromosome number in root tip cells of the species is found for the
first time to be 16, among which 6 are large, V-shaped with submedian primary constric-
tions, and the other 10 are short, rod-shaped  with terminal primary constrictions. Photomi-
crograph of the chromosome complement and idiogram are given in Fig. 1-3 respectively.
The karyotype formula of the species is therefore 2n=16=6m+6t+4t (SAT) in the light
of the chromosomal terminology defined by Levan and al.[5]
     Based on the view stressed by Jones[3] and Brandham[4], successive fusion of the ch-
romosomes should be taken as the essential mechanism for karyotype evolution and specia-
tion in Lycoris. Reciprocal translocation, with the loss of one of the centromeres, might be
the mechanism of origin for a V chromosome. It is, then, suggested that the decrease in ch-
romosome number as a result of fusion of the rods with terminal or subterminal primary
constrictions has taken place in the speciation of L. longituba.


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