- 作者: 吳大本
- 作者服務機構: 國立臺灣大學植物學系
- 中文摘要: 分析Stiposorghum亞屬內四物種(Sorghum intrans, S. matarankense, S. stipoideum和S. brevicallosum)的粗絲期染色體,知利用異染色質、核仁組成區、染色結、末端染色粒、染色體長度及長短臂率諸特徵能明確地識別各染色體。此四物種間雖相互不能雜交成功,但詳細分析比較它們的粗絲期染色體知四者之核型頗相似,其中尤以S. matarankense和S. stipoideum之粗絲期核型幾乎完全相同,但該二物種之核型與其餘二物種之核型則可藉核仁染色體數目不同而區別之。並由此等核型之異同探討物種間之相互關係。鏡檢此等物種之減數分裂,顯示粗絲期染色體配對之程度與趨動期染色體之交叉頻度關係密切;粗絲期染色體配對正常,則其趨動期染色體之交叉頻度增大,反之則交叉頻度減少。
- 英文摘要: The four Stiposorghum species (Sorghum intrans, S. matarankense, S. stipoideum and S. brevical-losum) are used as materials in this study. Based on the pachytene analysis here, it will be noted that each chromosome of these materialsexhibits a definite pattern such as length of heterochromatic regions, presence of deeply staining blocks,distribution of terminal knobs, distinct telochromomeric patterns and nucleolus organizers which, in com-bination with total length and arm ratio, makes it easy to identify individual chromosomes. Detailed comparisons of the pachytene karyotypes of these four species reveal no appreciable struc-tural differences other than differences in chromosome length and nucleolus chromosome number. Thesefacts show that the species of Stiposorghum appear to be closely related to one another. Although the karyotypes of Stiposorghums look like one another, a conspicuous difference in num-ber of nucleolus chromosomes at the pachytene is found in these materials: S. intrans has three chromo-somes which are associated with the same nucleolus; one with a subterminal point of attachment and twowith an intercalary point of attachment. S. matarankense as well as S. stipoideum has two nucleolus chro-mosomes, both associated with the same nucleolus; one with a subterminal nucleolus organizer and theother with an intercalary nucleolus organizer. S. brevicallosum has only one nucleolus chromosome whichpossesses an intercalary nucleolus organizer. By comparing karyotype differences among these species,interspecific relationships are speculated here. Meiotic analysis of these species shows the negative correlation to some extent between the amountof nonpairing at the pachytene and the mean chiasma formation at diakinesis.
- 中文關鍵字: Stiposorghum; pachytene analysis; nucleolus chromosomes; chiasma frequency
- 英文關鍵字: --