摘要:
多花水仙的染色体基数有x=10和x=11两类。基数x=10组型有两种,一种是具6长、4短的典型不对称的二形染色体组型;另一种是具有4长、2中、4短(或5长、2中、3短)的非二形染色体组型。基数x=11则具有4长、2中、5短(或5长、2中、4短)的非二型或非典型二形的染色体组型。x=10的典型不对称的二形染色体组型是原始的组型。基数x=11是从原始的x=10、2n=20组型中的(第5、6号)染色体发生不等长易位后,增加了一对短小的中着丝粒染色体而形成的。另一个x=10、2n=20的非二型新组型,可能从x=11组型丢失了短小的中着丝粒染色体衍生而来,也可能从易位后的个体所产生的不含中着丝粒染色体的雌、雄n配子结合而得到。
关键词:
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多花水仙
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染色体基数
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易位
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进化
Abstract:
There were two kinds of basic chromosome number, x=10 and x=11, in the polyanthous daffodils(Narcissus tazatta L.).The basic chromosome number x=10 with two kinds of karyotype, one was typical bimodal, i. e., all the chromosome in a set fall into two sharply defined classes, 6 long and 4 short ones; the other one was non-bimodal with 4(or5) long, 2 medium and 4(or3)short chromosomes in a set. The basic chromosome number x=11 was a non-bimodal or non-typical bimodal karyotype with 4(or 5)long, 2 medium and 5 (or 4)short chromosomes in a set.The bimodal karyotype of x=10 was an original one. The x=11 was derived from the original karyotype(x=10, 2n=20) by increasing a pair of short m chromosomes after reciprocal translocation of unequal chromosomal segments in two pairs of long chromosomes (No. 5and No. 6). The other one, x=10 2n=20, new non-bimodal karyotype may be a result of loss the short m chromosome from the x=11 2n=22 karyotype or combination of the male and female n gametes without the m chromosome after translocation.
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