首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到17条相似文献,搜索用时 125 毫秒
1.
毛冠菊属的花粉形态和结构及其系统学意义   总被引:1,自引:0,他引:1  
对国产菊科特有属的花粉形态和结构进行了光学显微镜、扫描电镜和透射电镜的观察和研究。该属的花粉可以分为圆球形、扁球形和长球形三种类型。种之间的花粉差异主要表现在大小、形状和外壁纺饰的细微变化等方面。与紫菀族、竿里光旋和旋覆共族三个族的代表种的花粉特征进行对比分析,并结合其它生物演化证据,可得取以下结论:(1)支持and-Mazzetti的分类意见,毽炙属应归于紫族中;(2)毛冠菊属的花粉可划分为圆球  相似文献   

2.
在扫描电镜下观察了毛冠菊属Nannoglottis 8种植物舌片的微形态特征,以探讨其颇有争议的系统位置。所有种类舌片近轴面的细胞为板状,长圆形;径向、切向壁直;外壁特征性突起,外壁中央为纵向皱纹,相邻细胞之间的纹饰无系统连接。这些特征表明毛冠菊属和紫菀族Astereae关系密切,但它在紫菀族内的系统位置可能比较特殊。这些结果和依据ITS序列推测的紫菀族系统发育的结果相吻合。文中还讨论了一些微形态性状的演化趋势以及微形态性状在毛冠菊属部分种类分类中的应用。  相似文献   

3.
本文研究了星叶草属的核形态。其间期核和前期染色体分别为简单染色中心型和中间型;中期染色体较小,长度介于3.00μm到1.20μm之间;核型公式为2n=30=22m+8sm。其明显很高的染色体基数以及其它退化和特化的形态学性状,表明该属是一个孑遗的古多倍体类群。该属与独叶草属在间期核形态、前期染色体形态以及中期染色体的大小和形态方面极为相似。结合其它方面的资料,本文认为星叶草属和独叶草属有较近的亲缘关系,支持将它们一起置于星叶草科的观点。  相似文献   

4.
建立了毛冠菊属的一个新组———单头组 ,并提出详尽的证据。  相似文献   

5.
穗花杉属的核形态及其系统位置的探讨   总被引:3,自引:0,他引:3  
研究了穗花杉Amentotaxus argotaenia和云南穗花杉A.yunnanensis的核形态。它们的有丝分裂间期核都为复杂染色中心型,前期染色体为中间型,中期染色体数目均为2n=36,核型相似,均为K(2n)=36=8m+28T,核型不对称性属于1B型,N.F.值为44。云南穗花杉的核型为首次报道。结合其它学科的资料,认为穗花杉属同榧属Torreya比较接近。  相似文献   

6.
报道了以3个不同居群为材料进行的拮筋条属核形态学研究结果。其间期核和前期核分别为简单染色体中心型和蹭型。染色体长度界于1.66μm至0.87μm之间,核型公式为2=28m+6sm,核型分类为1A型。相同的染色体基数及其与苹果亚科成员近似的核型,支持将牛条属置于苹果亚科,而不赞同将其归属于李亚科或另立亚科的观点。  相似文献   

7.
了款冬属的核形态。染色体间期为简单型与复杂型的过渡型;前期染色体为近基型的过渡型。染色体较小,核型不对称,具明显的二型性;数目与核型公式为2n=60=42m+10sm_6st+2t。比较发现款冬的核型不同于千里光族中已有的核型记载,其核型特征似乎与它独特的形态特征相联系,具有重要的系统学意义。  相似文献   

8.
刘建全 《植物研究》2000,20(3):313-317
研究了款冬属的核形态。染色体间期为简单型与复杂型的过渡型;前期染色体为近基型与中间型的过渡型。染色体较小,核型不对称,具明显的二型性;数目与核型公式为2n=60=42m+10sm+6st+2t。比较发现款冬的核型明显不同于千里光族中已有的核型记载,其核型特征似乎与它独特的形态特征相联系,具有重要的系统学意义。  相似文献   

9.
10.
假橐吾属(菊科:千里光族)的核形态研究   总被引:7,自引:0,他引:7  
首次发表假橐吾属Ligulariopsis Y.L.Chen的核形态研究结果。染色体间期为复杂型,前期染色体为中间型。染色体长度从2.70μm到4.70μm,平均长度为3.62μm,无明显的二型性;核型公式为2n=58=34m+18am(2sat)+6st,核型类型属于2A 。假橐吾属的核型和蟹甲草属与橐吾属相似,但假橐吾属具有较多的亚中部、中部着丝点染色体。  相似文献   

11.
This paper describes for the first time the karyomorphology of 4 populations of 2 species of Nannoglottis Maxim. s. l. The two species both show the resting nuclei of the complex chromocenter type and the mitotic prophase chromosomes of the interstitial type. The karyotype formula of N. gynura is 2n = 18 = 14m + 2sm + 2st(SAT) in two populations while that of N. carpesioides is 2n = 18 = 14m + 2sm(2SAT) + 2st in two populations. The two species under study represent two sections of Nannoglottis s. l. N. gynura, the only species of sect. Stenolepis, is considered as the most primitive member of the genus. Accordingly, the basic chromosome number of the genus might be x=9. Karyomorphological data indicate that Nannoglottis should be placed in the tribe Astereaerather than in the Inuleae and the Senecioneae.  相似文献   

12.
中国特有属——羽叶点地梅属的细胞学研究   总被引:1,自引:0,他引:1  
本文首次对中国特有的羽叶点地梅属Pomatosace Maxim.进行了细胞学研究。羽叶点地梅P. filicula Maxim.的间期核和有丝分裂前期染色体分别为复杂染色中心型和中间型;染色体数目为2n=20,核型公式为2n=18m+2sm;染色体大小介于6.4μm至4.1 μm之间;核型不对称性为2A型。细胞学证据支持羽叶点地梅属与点地梅属相近的观点。  相似文献   

13.
Investigated in the present work was the karyomorphology of Ligulariopsis Y. L. Chen. The interphase nuclei were categorized to be the complex chromocenter type, and the mitotic prophase chromosomes were categorized to be the interstitial type. The metaphase chromosomes ranged from 2.70 μm to 4.70μm with the average 3.62 μm in length. The karyotype was formulated as 2n = 58 = 34m + 18sm(2sat) + 6st and belonged to 2A type. The karyomorphological characteristics of Ligulariopsis are very similar to those of Ligularia and Parasenecio, but there are moresubmedian-centromeric and median-centromeric chromosomes in Ligulariopsis.  相似文献   

14.
Reported in this paper was the karyomorphology of the monotypic genus Pomatosace Maxim. The interphase nuclei and prophase chromosomes of P. filicula Maxim. were categorized to be complex chromocenter type and interstitial type respectively; themetaphase chromosomes were counted to be 2n = 20, ranging in length from 6.4µm to 4.1µm; the karyotype was formulated as 2n= 18m + 2sm, with the karyotype asymmetry belonging to 2A. The similar karyomorphological characteristics of interphase nuclei and prophase chromosomes between Pomatosace and Androsace, together with the similar sizeand morphology of their metaphase chromosomes, support the viewpoint that they are closelyrelated.  相似文献   

15.
The relationship ofAmbrosia (ragweed) andFranseria has long been debated. Their treatment as separate genera has been repeatedly challenged. In this study, chloroplast DNA restriction site variation was examined for species from bothAmbrosia andFranseria as well as taxa from the closely related genusHymenoclea. The chloroplast genomes of members of these three genera were examined using 21 restriction endonucleases and the restriction mutations were used to construct phylogenetic trees. Wagner and Dollo parsimony as well as weighted parsimony were employed to compare the different phylogenies. The results support a close relationship betweenAmbrosia andFranseria, but indicate that the two groups are well separated. Compared toFranseria, Ambrosia is a much more strongly supported group, and the results indicate thatHymenoclea is closer toFranseria than toAmbrosia. The cpDNA phylogeny was used as a framework to examine evolutionary trends in morphology and secondary chemistry.  相似文献   

16.
在光学显微镜和扫描电子显微镜下观察了蒺藜科四合木属四合木(Tetraena mongolica Maim.)木材结构.其导管分子直径小,管壁厚,分布密度高,分子短,端壁几乎水平,具单穿孔;管间纹孔为对列或互列的具缘纹孔;韧性纤维短、壁厚、壁上有较少的单纹孔;同型单列射线、分布密度高;轴向薄壁组织散生或傍导管生.这些表明四合木的木材解剖特征是与干旱环境条件是相适应的.  相似文献   

17.
双花木属和壳菜果属(金缕梅科)的核型研究   总被引:1,自引:1,他引:1  
本文对金缕梅科Hamamelidaceae双花木属Disanthus Maxim.的长柄双花木D.cercidifolius subsp.longipes和单种属壳菜果属Mytilaria Lec.首次进行了染色体计数和核型分析。结果表明:长柄双花木与产自日本的双花木D. cercidifolius subsp.cercidifolius的体细胞染色体数目一致,均为2n=16,前者无“st”或“t”染色体,表明该亚种可能比较原始;壳菜果Mytilaria laosensis Lec.的染色体数目为2n=26,x=13。前人报道的金缕梅科染色体基数为x=8和x=12,因此x=13可能是金缕梅科的一个新染色体基数。联系该属的形态特征及其与马蹄荷属Exbucklandia R.W.Brown的关系,作者支持将壳菜果属处理为独立的亚科,即壳菜果亚科Mytilarioideae。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号