新疆野生油菜细胞遗传学研究

Studies on Cytogenetics of Xinjiang Wild RapeⅡ. Analysis on Morphological Characteristics of Chromosomes,Isozymes of Peroxidase,Mitochondrial DNA

对７０个不同编号的新疆野生油菜和黑芥进行了染色体形态特征、过氧化物酶同工酶和ｍｔＤＮＡ的研究，结果表明：新疆野生油菜的染色体数为２ｎ＝１８，不同于黑芥（Ｂ．ｎｉｇｒａ）尤嫩斯２ｎ＝１６。新疆野生油菜与黑芥的核型都为Ｂ型，但染色体比不同，新疆野生油菜的染色体比小于黑芥。用吉姆萨染色，新疆野生油菜带型不同于黑芥，最明显的差异是新疆野生油菜有一对染色体显全带，表示为组成型异染色质，而黑芥没有。过氧化物酶酶带的明显差异是新疆野生油菜比黑芥多一条酶带。ｍｔＤＮＡ分析表明，新疆野生油菜与黑芥都有主带ＤＮＡ分子，但新疆野生油菜还有两条质粒状ＤＮＡ带，而黑芥没有。由此认为新疆野生油菜与黑芥不是同一个种，但亲缘关系密切，并推测在黑芥的演化过程中，新疆野生油菜可能是最原始的类型，到现在或许还有少数的过渡类型。

The morphological characteristics of chromosomes,isozymes of peroxidase mitochondrial DNA of seventy different number's Xinjiang wild rape and Brassica nigra were studied in this paper. The results showed that morphological characteristics of chromosomes can all be described as chromosomal number of Xinjiang wild rape is 2n= 18. It is different with B.nigra(Juntus)2n=16.The chromosomal karyotype of Xinjiang wild rape is the same with B.nigra,that is B type,but there is difference in chromosomal ratio between Xinjiang wild rape and B.nigra, Xinjiang wild rape chromosome ratio less than B.nigra. After chromosomes stained with Giemsa,the chromosomal banding patterns of Xinjiang wild rape are different with B.nigra.The most obvious difference is that there are one pair chromosome showed whole band in Xinjiang wild rape,it demonstrates constitutive heterochromatin. But there aren't one in B.nigra.There is obvious difference in isozymes bands of peroxidase between Xinjiang wild rape and B.nigra. The isozymes bands of Xinjiang wild rape is one band more than B.nigra.An analysis on mitochondrial DNA showed that there are all of main band DNA molecule in Xinjiang wild rape and B.nigra. There are also two plasmidlike DNA bands in Xinjiang wild rape but there aren't plasmidlike D N A bands in B.nigra.It could therefore be considered as Xinjiang wild rape and B.nigra aren't the same species, but it has a close related with B.nigra and supposed during evolution process of B.nigra the Xinjiang wild rape(2n=18)is orginalest type. Perhaps,there are a few middle type between Xinjiang wild rape and B.nigra have kept until present.