ISSN:
1442-1984
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Abstract Fifteen Asiatic and four North American taxa of the genus Disporum (Liliaceae-Polygonateae) were karyologically examined. The chromosome numbers and karyotypes of D. multiflorum (2n= 14), D. sessile var. sessile f. minus (2n= 16), D. sessile var. micranthum (2n= 16), and D. taipingense (2n= 16) were determined for the first time. Thirteen additional chromosome counts and karyotype analyses were made for the following 11 Asiatic Disporum taxa (Section Disporum): D. calcaratum (2n= 14 and 16-a new count), D. cantoniense (2n= 14 and 16), D. kawakamii (2n= 16), D. longistylum (2n= 16), D. lutescens (2n= 16), D. sessile var. sessile f. sessile (2n= 16), D. shimadai (2n= 14), D. smilacinum var. smilacinum (2n= 16), D. smilacinum var. ramosum (2n= 16), D. uniflorum (2n= 16), and D. viridescens (2n= 16 + 1B-a new count).The karyotypes of four North American taxa (Section Prosartes) were reported for the first time, although the same chromosome counts had been previously known for each taxon: D. hookeri (2n= 18), D. lanuginosum (2n= 18), D. maculatum (2n= 12), and D. smithii (2n= 16). D. maculatum possesses a very characteristic satellite on the long arm of the fifth subterminal chromosome; the karyotype of D. smithii (x= 8) is also characterized by possessing a minute satellite on the short arm of the fifth pair and also by a secondary constriction on the short arm of the sixth pair.One of the most noteworthy findings made in the present study is that the species of Section Disporum and Section Prosartes possess conspicuously distinct cytological features in the size of resting nuclei and cells, interphase chromosomes, and mitotic prophase and metaphase chromosomes. The plants of Section Disporum have distinctly larger resting nuclei and cells than those of Section Prosartes; Section Disporum possesses a typical homogeneously diffused type (= densely diffuse type according to Tanaka, 1977) of interphase chromosomes, while Section Prosartes has a prochromosome type; the condensation pattern of their prophase chromosomes is of a continuous type in Section Disporum, while a proximal type occurs in Section Prosartes; Section Disporum possesses distinctly larger sized metaphase chromosomes, as compared with Section Prosartes. All of these karyological differences described above strongly support D. Don's original concept (1839, 1841) of treating Disporum and Prosartes as two separate genera.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1442-1984.1992.tb00224.x
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