摘要
报道了国产赖草属 5个种的核型 ,即大赖草 ,2 n=4x=2 8=2 4 m ( 2 SAT) + 4 sm( 2 SAT) ;粗穗赖草 ,2 n=4x=2 8=2 2 m( 2 SAT) + 4 sm+ 2 st( 2 SAT) ;若羌赖草 ,2 n=4x=2 8=2 0 m( 4 SAT) + 6sm+ 2 st( 2 SAT) ;羊草 ,2 n=4x=2 8=2 2 m( 4 SAT) + 2 sm+ 4 st( 4 SAT) ;窄颖赖草 ,2 n=4x=2 8=2 2 m( 2 SAT) + 4 sm( 2 SAT) + 2 st( 2 SAT)。同时 ,根据 Stebbins的核型进化理论和分支系统学的编序赋值方法 ,对核型 4个重要性状进行了分析 ,总结出了 5个种的进化指数 ,并同外部形态演化分析相印证 ,揭示了宏观分类中 3个组的系统发育水平。
The karyotypes of 5 species of Leymus Hochst.are reported in this paper.The karyotype formulae are as follows: L.racemosus (Lam.) Tzvel.,2n=4x=28=24m(2SAT)+4sm(2SAT); L.crassiusculus L.B.Cai,2n=4x=28=22m(2SAT)+4sm+2st(2SAT); L.ruoqiangensis S.L.Lu et Y.H.Wu,2n=4x=28=20m(4SAT)+6sm+2st(2SAT); L.chinensis (Trin.) Tzvel.,2n=4x=28=22m(4SAT)+2sm+4st(4SAT); L.angustus (Trin.) Pilger.,2n=4x=28=22m(2SAT)+4sm(2SAT)+2st(2SAT).Furthermore,according to Stebbins theory of the karyotypic evolution as well as using the method of coding of cladistics,4 significant characters,the ratio of the longest chromosome to the shortest,the arm ratio in mean,the index of the karyotypic asymmetry and the proportion of chromosomes with arm ratio>1.70,were analysed,the evolutional levels of 5 species were also affirmed.And the result of cytological analysis is consistent with the morphological result analysed with the evolutionary trends of external characters.Both of cytological and morphological evidences indicate that the Sect.Leymus of Leymus Hochst.is a relatively primitive section,the Sect.Anisopyrum (Griseb.) Tzvel.a advanced section,and the Sect.Aphanoneuron (Nevski) Tzvel.is between them.
出处
《西北植物学报》
CAS
CSCD
2000年第5期876-881,共6页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金资助项目!( 3 9870 0 90 )
