以崇明水仙(Narcissus tazetta L. var. chinensis Roem.)根尖体细胞为实验材料,对适宜于崇明水仙细胞学研究的前处理液和前处理时间进行了筛选,在此基础上,应用根尖压片法对重瓣花型和单瓣花型崇明水仙体细胞染色体数、核型及倍性进行了比较分析。 结果显示:适宜的前处理液是对二氯苯饱和溶液,适宜的前处理时间为 12 h。重瓣花型和单瓣花型崇明水仙的染色体核型差异较小,相同点为:不对称二型核型,染色体基数 x = 10,三倍体,体细胞染色体数 2n = 3x = 30,第 7 号染色体的短臂具随体,核型均属于“3B”型,臂比大于 2 的染色体比率为 90% 。 不同点为:重瓣花型的第 7 号和第 8 号染色体分别为 sm 和 st 型,单瓣花型的第 7 号和第 8 号染色体分别为 st 和 sm型;前者的核型不对称系数(76. 48% )略小于后者(76. 71% );前者的相对长度系数为 12L+6M2 +12S,后者的相对长度系数为 12L+3M1 +3M2 +12S;前者的最长染色体与最短染色体长度的比值(3. 10)略小于后者(3. 19)。 重瓣花型的核型公式为 2n = 3x = 30 = 15st+15sm(3SAT),单瓣花型的核型公式为 2n = 3x = 30 = 15st(3SAT) +15sm,崇明水仙根尖体细胞染色体的平均核型公式为 2n = 3x = 30 = 15st(3SAT) +15sm。 根据研究结果初步推测崇明水仙为节段异源三倍体。


 

Using somatic cells in root-tips of Chongming narcissus ( Narcissus tazetta L. var. chinensis  Roem.) as experimental materials, pre-treatment solution and time being suitable for cytology research were selected. On above basis, chromosome number, karyotype and ploidy in somatic cells of double and single flower types of Chongming narcissus were analyzed and compared by root-tip pressing flake method. The results show that suitable pre-treatment solution and time are p-dichlorobenzene saturated solution and 12 h, respectively. Difference of chromosome karyotype between double and single flower types of Chongming narcissus is a little. Their common features are: bimodel asymmetric karyotype, basic chromosome number x = 10, triploid, somatic cell chromosome number 2n = 3x = 30, with a satellite on the short arm of No. 7 chromosome, karyotype belonging to “3B” type and 90% chromosome with an arm ratio more than 2. Their different features are: No. 7 and No. 8 chromosomes are sm and st types in double flower type and are st and sm types in single flower type, respectively, the asymmetrical karyotype coefficient of the former (76. 48% ) is slightly lower than that of the latter (76. 71% ); the index of relative length of the former is 12L+6M2 +12S while that of the latter is 12L+3M1 +3M2 +12S; the length ratio of the longest chromosome to the shortest chromosome of the former (3. 10) is slightly smaller than that of the latter (3. 19). Karyotype formula of double flower type is 2n = 3x = 30 = 15st+15sm(3SAT) and that of single flower type is 2n = 3x = 30 = 15st(3SAT) +15sm, and average karyotype formula is 2n =3x = 30 = 15st(3SAT) +15sm. According to these results, it is conjectured preliminarily that Chongming narcissus is segmental allotriploid.