四倍体不结球白菜的诱导及染色体倍性鉴定

用不同浓度秋水仙素处理子叶期不结球白菜生长点对其进行染色体倍性操作,根据形态解剖学、细胞学特征和流式细胞仪进行倍性鉴定.结果表明,浓度为0.2%的秋水仙素处理4次的效果最好,四倍体诱变率为8.42%.与二倍体相比,四倍体植株叶片、花器官、气孔等均表现巨大性;气孔密度和结实率降低;抽薹较晚.用流式细胞仪进行倍性鉴定,对照DNA相对含量为100,疑似株为200,表明是四倍体;疑似株有2个值与对照的比值约为1和2,表明是嵌合体(2x 4x).流式细胞仪鉴定结果与染色体计数法鉴定结果一致,表明流式细胞仪可以较准确地检测不结球白菜突变株倍性.

Induction of Tetraploidy of Non-heading Chinese Cabbage with Late-bolting and Identification of Chromosome Configuration

Tetraploid plants of non-heading Chinese cabbage(Brassica campestris ssp.chinensis Makino) were induced by treating the apical portion of seedlings with different solution of colchicines.Autotetra ploid plants were selected and identified based on morphological,anatomic,agronomic,cytological observation and flow cytometry.The results showed that the treatment with 0.2%colchicine for 4 times yielded doubled chromosomes at highest rates and the rate of tetraploid was 8.42%.Compared with the diploid,the autotetraploid plants possessed gigantism in leaves,stomata,flowering organs of plants.The density of stomata and fecundity were reduced remarkably.The bolt of tetraploid was later.The flow cytometry was used to identify the ploidy of induced-plants.The result suggested that the relative DNA content of CK was 100,and tetraploid relative DNA content was 200.There were two peak in one plant and the ratio were 1 and 2 with CK indicating chimeras(4x 2x).The identified result of flow cytometry was accorded to that of chromosome analysis,implied the flow cytometry could identify the ploidy of non-heading Chinese cabbage accurately.