CYTOTAXONOMY OF CESPITOSE ZINNIAS

Torres , Andrew M. (U. Wisconsin, Milwaukee.) Cytotaxonomy of cespitose zinnias. Amer. Jour. Bot. 49(10): 1033–1037. Illus. 1962.—The results of hybridization studies among 5 of the 6 cespitose species of Zinnia are reported. Analyses of meiosis in the F₁ hybrids suggest there are 2 genomes, A and B, in the polyploid taxa. The A genome apparently exists in the diploid state in 2 species, but the B genome is known only from polyploid taxa. The chromosome number of Z. oligantha (2n = 20) is reported for the first time.     

塔里木兔的核型分析

塔里木兔是兔科(Leporidae)动物适应干旱荒漠生境形成的一特殊物种,无论在形态结构或生理-生态适应等方面,均表明其为典型的荒漠栖居者。本种广布于塔里木盆地内的农垦绿洲、胡杨林、柽柳灌丛、盐生草甸、戈壁和沙漠边缘的固定与半固定沙丘等多种自然景观中,为盆地特有种。 Hsu,T.C.等(1967,1970,1971)曾报道Lepus americanus等6种兔科动物的核型,Chiarell,A.G.和I.Capana(1973)汇集了学者们早期研究该科Lepus alleni等14种的核型资料,而塔里木兔的核型至今未见报道。本文对其作了观察分析,结果如下。     

BrdU-Hoechst-Giemsa方法的进一步改进以及青鱼和草鱼复制带核型的研究

对BrdU-Hoechst-Giemsa方法进行了一定的改进和补充;并将它应用于青鱼和草鱼的核型研究中。实验进一步阐明,BrdU-Hoechst-Giemsa方法的关键性步骤之一是要先测算实验鱼的细胞周期;BrdU、AMD、Hoechst 33258,EB和AO虽都有抑制鱼类染色体浓缩、促进染色体分带的作用,但其中以DNA碱基特异性给合物BrdU、AMD和Hoechst 33258较佳,特别用AMD和Hoechst 33258同时处理活细胞的分带效果最好。     

THE CYTOLOGY AND PHYLOGENETICS OF THE DIPLOID SPECIES OF GOSSYPIUM

Meiotic chromosome behavior of 11 inter-genomic hybrids of Gossypium (2n = 26) were investigated. Per cell univalent frequencies at meiotic metaphase I in these hybrids were: A genome × Cgenome—G. herbaceum × sturtianum, 10.53; G. herbaceum × australe, 18.05. A genome × E genome—G. smnalense × arboreum, 21.82. B genome × C genome—G. anomalum × sturtianum, 9.23; G. anomalum × australe, 13.11. B genome × D genome—G. anomalum × klotzschianum, 17.45; G. anomalum × raimondii, 18.83. C genome × D genome—G. robinsonii × davidsonii, 12.77; G. sturtianum (armourianum × thurberi), 8.63. C genome × E genome—G. somalense × australe, 23.78; G. somalense × bickii, 25.58. Trivalent and quadrivalent frequencies were relatively high for those hybrids involving a C genome species, indicating that a reciprocal translocation differentiates the C genome from the A, B, D, and E genomes. The results of this study and the data of similar studies cited from the literature on Gossypium cytogenetics are discussed relative to the phylogenetics and evolution of the major (genome) groups of Gossypium and their constituent taxa.     

扁柏属的核型及柏本亚科的细胞分类学研究

分析了美国扁柏、日本扁柏和日本花柏的核型,它们的核型公式分别为Ｋ（２ｎ）＝２２＝２２ｍ,２０ｍ＋２ｓｍ和１４ｍ＋８ｓｍ。作者比较了扁柏属６个代表种的核型,发现北美种类有比东亚种类原始的趋势。在柏本亚科中,扁柏属可能最进化,柏木属最原始,福建柏属和杂交属×Ｃｕｐｒｅｓｓｏｃｙｐｅｒｉｓ居中。论文还讨论了柏木和福建柏的系统位置。     

油桐和木油数核型的研究

油桐Vernicia fordii (Hemsl.) Airy-Shaw (Aleurites fordii Hemsl.)和木油树V. montana Lour. (A. montana (Lour.) Wils.)为大戟科油桐属Vernicia Lour. 植物,全世界共3种,上述两种为原产我国的重要木本油料植物,长江以南各省(区)广为栽培。细胞学方面,这两个种的染色体计数有过不少报道,均为n=11。本文旨在提供这两种植物核型比较分析的资料,以冀有助于它们选种育种工作。     

莲属(Nelumbo)20个品种染色体数目及其核型分析

本文对现有野生和栽培的128个莲藕品种中,有代表性的20个品种,进行了体细胞染色体的形态结构及核型分析,发现所有品种均为二倍体,染色体基数为8,2n=16。就染色体形态结构、相对长度变化范围、著丝点位置看,各品种基本核型组成大致近似,不同点是带随体的位置数目不一,以及每对染色单体有缺失现象。这很可能会引起某些染色体产生包括易位在内的结构重组,从而导致各品种之间的差异。     

贵州两种黄脊蝗核型和C－带的比较研究

本文研究了贵州日本黄脊蝗ＰａｔａｎｇａｊａｐｏｎｉｃａＢｏｌｉｖａｒ和印度黄脊蝗Ｐ．ｓｕｃｃｉｎｃｔａＪｏｈａｎｓｓｏｎ的核型和Ｃ－带。结果表明：两种黄脊煌的染色体数目均为２ｎ＝２２＋Ｘ０＝２３,全部为端着丝粒染色体;核型公式２ｎ＝２Ｘ＝２３ｔ,ＮＰ＝２３．但日本黄脊蝗的染色体绝对长度总和（７９．７５±２．２２μｍ）比印度黄脊蝗的（７１．４７±０．６３μｍ）长;异染色质总量《３５．６５±０．１４μｍ）比印度黄脊蝗的（１８．７６±０．１１μｍ）多;日本黄脊蝗的核型属“ＩＢ＂核型,印度黄脊蝗的核型属“ＩＣ”核型。     

五种啮齿类动物核型和血清蛋白质的SDS-聚丙烯酰胺凝胶电泳分析

本文对5种啮齿类动物(岩松鼠、花鼠、五趾跳鼠、棕背(鼠平)和岢岚绒鼠)的核型及其血清蛋白质的SDS-聚丙烯酰胺凝胶电泳进行了分析。通过分析结果,探讨了它们的核型及血清蛋白在其分类中的意义。     

A TECHNIQUE FOR THE ANALYSIS OF EPISTATIC GENE ACTION I. THE METHOD OF ANALYSIS

The thirty-two possible genic crosses involving two pairs of nonlinked genes were simulated. The anticipated progeny of each cross was analyzed according to each of the seven basic types of epistatic action. A key was devised to facilitate the recognition of genic action since most phenotypic progeny ratios are produced exclusively either by phenotypically similar parents or phenotypically dissimilar parents. Only ratios of 3:1, 2:1, and 1:1 can be produced by both types of parents.     

水稻PDER品系的特点和二倍体孢子生殖胚囊的形成和发育

对水稻（ＯｒｙｚａｓａｔｉｖａＬ．）早发生胚ＰＤＥＲ（ｐｒｅ－ｄｅｖｅｌｏｐｅｄｅｍｂｒｙｏｏｆｒｉｃｅ）品系的特点和细胞胚胎学研究表明,ＰＤＥＲ是二倍体植物２ｎ＝２４,约有５０％胚囊的卵细胞未经受精能自行发育形成胚,成熟种子的萌发和生长速度较常规正常水稻快。ＰＤＥＲ的大孢子母细胞经有丝分裂产生未减数的胚囊,即无融合生殖中的二倍体孢子生殖类型。在胚囊形成和发育过程中有如下几个特点：（１）孢原细胞至大孢子母细胞分裂前的过渡期持续时间较长,孢原细胞和大孢子母细胞的细胞质比周围的珠心细胞质稀淡。（２）大孢子母细胞经二次有丝分裂后形成直线排列的三个细胞（三分体）,珠孔端的两个解体,合点端的一个发育为功能细胞,有少数胚囊的三个细胞全部解体形成败育胚囊。（３）功能细胞经三次连续核分裂形成具八核七个细胞的成熟胚囊,它的结构与常规正常水稻基本相同,但助细胞呈长形而没有回抱着卵细胞。     

GENETIC DIFFERENTIATION,SYMPATRIC SPECIATION,AND THE ORIGIN OF A DIPLOID SPECIES OF STEPHANOMERIA

Evidence is presented that a geographically peripheral population of the annual Stephanomcria exigua ssp. coronaria (Compositae), a widespread and ecologically diverse species, has recently given rise by a process of sympatric speciation to a diploid species presently designated “Malheurensis.” The new species comprises less than 250 individuals and is found only at a single locality in eastern Oregon where it grows interspersed with its parental population. Stephanomeria exigua ssp. coronaria is an obligate outcrosser and “Malheurensis” is highly self-pollinating. Reproductive isolation is maintained by differences in breeding system, a crossability barrier that reduces seed set following cross-pollination between them, and reduction in hybrid fertility caused by chromosomal structural differences. They are very similar morphologically. Electrophoretic analyses of seven enzyme systems demonstrate that all the alleles but one at the controlling 13 gene loci in “Malheurensis” are identical to alleles in ssp. coronaria. The new species displays certain maladapted features including loss of the specific requirements for seed germination characteristic of the progenitor population of ssp. coronaria. The origin of “Malheurensis” appears to be an exception to the theory of geographical speciation because spatial isolation is not necessary at any time for the origin or establishment of its reproductive isolating barriers. The nature of these barriers plus the genetic homogeneity of the species are compatible with the hypothesis that it derives from a single progenitor individual. Very little genetic change is involved initially in this mode of speciation.     

二倍体野生棉的核型变异和进化

本文对棉属(Gossypium)二倍体野生种5个组的代表种即 B_1(G.anomalum),C_1(G.sturtianum),E_1(G.stocksii),F(G.longicalyx)和 G(G.bickii)的核型进行了分析。提出分布于非洲南北的 B 组野生种为最原始的类型,以此为中心呈辐射状分化和迁移,形成了现今的特殊的地理分布。     

六角莲及其近缘的核型和演化的研究

本文首次报道我国特产的药用植物六角莲的核型,K(2n)=12=8m(2SAT)+2st(SAT)+2t,为“2A”型。与桃儿七(属)和足叶草(属)的核型比较接近,反映了它们的近缘关系。但又似以六角莲(八角莲属)最原始,它可能通过二条路线演化到桃儿七属和足叶草属并以后者最为进化。笔者认为八角莲属和桃儿七属从足叶草属的分立及应俊生提出的从前者演化出后二者的演化趋势得到细胞学资料的支持。本研究还支持吴征镒等关于我国西南和南部到东南亚的北部是东亚-北美区系成分的发源地的意见。     

远东刺猬和大耳猬的核型分析

远东刺猬和大耳猬的二倍体染色体数目均为2n=48。远东刺猬的核型组成为13m+6sm+3st+1t+XY,NF=92,C带分布于5对近端和亚中着丝粒染色体的长臂,约占整个染色体长臂的1/2至2/3,Ag-NOR_5,位于2-3对染色体的长臂端部;大耳猬的核型组成为18m+4sm+1st+XY,NF=92,C带分布于17对染色体的着丝粒部位,Ag-NOR_5位于3-5对染色体上,其中—Ag-NOR位于染色体的长臂中部,两者的核型特征有明显区别,结合前人的工作,作者提出在远东刺猬的不同地理居群中至少存在三种不同的核型。本文对普通刺猬属的远东刺猬、东欧刺猬和西欧刺猬的核型以及大耳猬属的大耳猬、达乌尔刺猬和秦岭短棘猬的核型还分别作了比较分析。此外,对远东刺猬联会复合体的形态、性染色体的配对行为和SC侧线加厚现象也作了分析讨论。