四种鹅观草核型分析及与披碱草属核型比较

KARYOTYPE ANALYSIS OF 4 SPECIES OF ROEGNERIA AND A COMPARISON WITH ELYMUS (GRAMINEAE)

本文报道了直穗鹅观草(Rvegneria turezain(?)i)、吉林鹅观草(R.nakaii)、多叶鹅观草(R.foliosa)及毛节毛盘草(R.barbicalla var. pu(?)odis)4种植物的体细胞核型,并将其与披碱草属植物的核型进行了比较。这4种鹅观草均为四倍体,2n=4x=28,对称性核型,具有一长两短的3对随体染色体,或仅具两对随体。国产披碱草属90％的种类为六倍体,2n=6x=42,具有两长一短的3对随体染色体。因此,本文认为鹅观草属与披碱草属在染色体倍性水平及形态上存在明显区别,主张将二者分别作为独立的属对待。

The karyotype of four species of Roegneria is presented. Each of these four species is tetraploid(2n=28) and exhibits an symmetrical karyotype. The karyotype formulas are as folows: R. turc(?)aninorü: 2n=4x=28=26m (4SAT)+2sm(2SAT), R. nakaü: 2n=4x=28=24m (2SAT)+4sm(4SAT), R. foliosa: 2n=4x=28=26m(6SAT)+2sm, R. barbicalla var. pubinolis : 2n=4x=28=26m(2SAT)+2sm(2SAT). The karyotype of Roegneria was also compared with that of Elymus. The results indicate that there are some distinct differences in ploidy level and in then number and length of the satellites between these two genera. Roegneria is always tetraploid, while 90 persent of Chinese Elymus is Hexaploid. In Roegneria there are one long and two short satellites,while in Elymus two are long and one is short. Also, these are sometimes only two pairs of satellites in Roegneria. The recognition of these two genera as two separate genera is fully justified.