摘要
边陲黄耆和乌拉特黄耆间断分布于蒙新荒漠的西侧和东侧 ,二者在外部形态上接近 ,是一对易混淆的种。对这两个种的核型研究表明 ,边陲黄耆的核型公式为 2 n=1 6=1 0 m( 2 SAT) + 6st,其中第 1、2、3号染色体较长 ,其余染色体较短 ,核型呈现出明显的二型性 ,在第 4号染色体 ( m型 )长臂上有明显的随体 ,而乌拉特黄耆的核型公式为 2 n=1 6=6m+ 6sm+ 4 st( 2 SAT) ,其中除第 1号染色体较长外 ,其余染色体相互之间的长度差异不明显 ,核型的二型性不明显 ,在第 1号染色体 ( st型 )短臂上有明显的随体。在地理分布上 ,前者分布于蒙新荒漠的西侧 ,后者分布于蒙新荒漠的东侧 ,中间为一干旱核心地带所隔离。说明两个类群的核型差异和地理分布已经远远超出种内变异的水平 ,应被视为两个不同的物种。
Astragalus dshimensis Gontsh.and A.hoantchy Franch.are one pair of disjunctive species between the eastern and the western parts of Mongolia-Xinjiang Desert.Because of their morphological similarities,they were treated as two subspecies under the name A.hoantchy in (Flora of China).According to our analyses of their karyotypes and their distribution patterns,we think they are two different species with clear distinctions in cytology and phytogeography.The karyotype formula of A.dshimensis is 2n=16=10m(2SAT)+6st.Among its 16 chromosomes,the 1st,2nd and 3rd ones are much longer than others else are,with a result that the dichotocarpism of its chromosomes is clear.There is an obvious satellite on the long arm of its fourth chromosome and this chromosome is m type.In contrast,the karyotype formula of A.hoantchy is 2n=16=6m+6sm+4st(2SAT),and among its 16 chromosomes only the first one is longer than others are,so the dichotocarpism of its chromosomes is unclear.The satellite is on the short arm of its first of chromosomes and this chromosome is st type.Besides above, A.dshimensis is distributed in western part of Mongolia-Xinjiang Desert while A.hoantchy is in eastern part of that desert.Between them exists a dry and arid core belt and the two species are completely isolated by it.Obviously,the two species are good and different species and the name A.dshimensis should be resumed according to our present study.
出处
《西北植物学报》
CAS
CSCD
2000年第3期415-420,共6页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金资助项目!( 3 9570 0 55)
