【作者】 王芳；

【导师】 周兰英；

【作者基本信息】 四川农业大学 ， 园林植物与观赏园艺， 2011， 硕士

【摘要】 榕属(Ficus L.)隶属于桑科(Moraceae),包括4个亚属,全世界约1000种,是一类具有多种观赏价值的树木。目前,世界各地对于榕属植物的研究,主要集中在榕属植物与其专性寄生榕小峰的互惠共生关系以及部分榕属植物的生物学特性上,对于其细胞学方面的研究,国外未见报道,国内报道的也仅有少数几种。因此,本研究以高山榕(F. altissima)、菩提树(F. religiosa L)、小叶榕(F. microcarpa)三种榕属植物种子萌发的根尖为材料进行染色体常规压片后,对它们的核型进行了分析研究,以期为榕属植物的亲缘关系研究、杂交育种及分类鉴定等提供重要的参考价值,也为今后榕属的研究深入到基因水平、分子水平奠定基础,使榕属的研究更加科学而全面。主要结果如下：1、高山榕、菩提树、小叶榕三种植物的种子都较小,实验特别分析了取材长度的不同对常规压片效果的影响。发现,所取根尖过长时,压片后分生区细胞较少,影响观察；根尖过短又不利于操作；合适的取材范围为0.3-0.5cm。2、常规压片法阶段。高山榕、菩提树、小叶榕三种植物在预处理方法上比较一致：它们的最适预处理条件为0.05%秋水仙素和0.002mol·L-18-羟基喹啉体积比1：1混合液低温0-4℃处理24h,但菩提树在三种预处理后的差异不是特别显著,可以说用0.05%的秋水仙素溶液低温0-4℃处理24h与0.002mol·L-1的8-羟基喹啉溶液低温0-4℃处理24h这两种预处理方法对于菩提树也较适用。经卡诺固定液暗处固定18-24h。三种植物在解离时间上存在明显差异：高山榕根尖用lmol·L-1 HC1在60℃下处理1-2min为宜,菩提树根尖用lmol·L-1 HC1在60℃下处理约1min为宜,小叶榕根尖用lmol·L-1 HC1在60℃下处理2-3min为宜。用改良苯酚品红染色后压片。3、高山榕、菩提树、小叶榕的体细胞染色体数目均为2n=30。4、高山榕的核型公式为2n=2x=30=22m(2SAT)+6sm+2T,染色体平均长度为2.80μm,核型不对称系数为61.54%,核型类型为“2C”型。菩提树的核型公式为2n=2x=30=24m(2SAT)+6sm,染色体平均长度为3.30μm,核型不对称系数为60.28%,核型类型为“1B”型。小叶榕的核型公式为2n=2x=30=28m(2SAT)+2sm,染色体平均长度为3.44μm,核型不对称系数为58.16%,核型类型为“1B”型。三者均属于小型和中等大小染色体,均含有一对具随体染色体。高山榕与菩提树、小叶榕的核型差异较大,而菩提树与小叶榕的核型差异相对较小。5、高山榕、菩提树、小叶榕三者的核型不对称程度为：小叶榕<菩提树<高山榕。从亲缘关系看,高山榕与菩提树、小叶榕的亲缘关系较远,为较进化的类型；菩提树和小叶榕亲缘关系较近,为较原始的类型。更多还原

【Abstract】 Ficus L. which is belonging to Moraceae, includs 4 subgenus and about 1000 species, is a kind of trees possessing various ornamental value. At present, there are mang studies about Ficus L., which mainly centralized at figs-pollinators mutualism relation and biological feature of some fig trees. There are little of cytological studies about Ficus L.. Therefore, the chromosome karyotype of F. altissima, F. religiosa L. and F. microcarpa were investigated with the conventional pressing plate method, by which, I wish to provide some import refence to relationship researches, cross breeding, classification and identification etc. of Ficus L., lay a foundation of another studies of Ficus L.. The results showed:1、The seeds of F. altissima, F. religiosa L. and F. microcarpa are very small. The effects of conventional squash with different length of root-tip were studied. The reselts showed that the cells of meristematic zone were fewer after squashing when the length of root-tip were longer, which affacted on observation. The length of root-tip which were shotter made against operation. The suitable length of root-tip were 0.3-0.5cm.2、The stage of conventional squashing. The pretreatments of F. altissima, F. religiosa L. and F. microcarpa were unanimous basically. The best pretreatment method was mixture (0.05% colchicine and 0.002 mol·L-1 8-hydroxyquinoline by volume ratio 1:1) with lower temperature at 4℃for 24h. But the differences of three pretreatments of F. religiosa L. were not significant, what is the other two pretreatments(0.05% colchicine with lower temperature at 4℃for 24h and 0.002 mol·L-1 8-hydroxyquinoline with lower temperature at 4℃for 24h) were relatively suitable for F. religiosa L.. The root-tips were fixed with Camoy solution for 18-24 h in the dark. The differences of dissociation methods of three plants were significant. The best dissociation method of F. religiosa L. was 1 mol·L-1HCl with 60℃lasted 1-2 min. The best dissociation method of F. altissima was 1 mol·L-1HC1 with 60℃lasted about 1 min. The best dissociation method of F. altissima was 1 mol·L-1HCl with 60℃lasted 2-3 min. The stained with modified Carbol fuchsin solution. 3、The number of chromosome of F. altissima, F. religiosa L. and F. microcarpa are 2n=30.4、The karyotype formulae of F. altissima was 2n=2x=30=22m(2SAT)+6sm+2T, the average length of chromosome was 2.80μm, belonging to "2C" type. Its index of Asymmetric was 61.54%. The karyotype formulae of F. religiosa L. was 2n=2x=30=24m(2SAT)+6sm, the average length of chromosome was 3.30μm, belonging to "1B" type. Its index of Asymmetric was 60.28%. The karyotype formulae of F. microcarpa was 2n=2x=30=28m(2SAT)+2sm, the average length of chromosome was 3.44μm, belonging to "1B" type. Its index of Asymmetric was 58.16%. The chromosome of three plants were belonging to miniature or medium type chromosome, and all of them included a pair of satellite chromosomes. F. altissima is significantly different from F. religiosa L. and F. microcarpa in karyotype, but the differences between F. religiosa L. and F. microcarpa is not significant.5、The order of asymmetry index of F. altissima, F. religiosa L. and F. microcarpa is F. microcarpa<F. religiosa L.<F. altissima. F. altissima has a distant relationship to F. religiosa L.and F. microcarpa, F. religiosa L.has a near relationship to F. microcarpa. It is showed that F. religiosa L.and F. microcarpa may order than F. altissima.更多还原