CHROMOSOME NUMBERS IN PURE AND GROSS CULTURES OF MYXOMYCETES

Certain strains of Myxomycetes grown in pure culture in liquid media display widely varying chromosome numbers which indicate the presence of polyploid series of amoebae and plasmodia. The implications of these chromosome number variations on existing controversies concerning Myxomycete life cycles and cytology are discussed.     

SOME CHROMOSOME NUMBERS OF DRAPARNALDIA

The variability exhibited by Draparnaldia both in nature and in the laboratory makes it difficult to identify the species. The natural variability of Draparnaldia was amplified by the environmental conditions and the media used in this study. With the hope that chromosome studies would aid in taxonomic characterization by providing additional differentiating criteria, special attention was devoted to adapting techniques which could be used to determine chromosome numbers of Draparnaldia isolates. The chromosome numbers reported herein are as follows: (1) Draparnaldia glomerata, Isolate #1, isolated from Davis Falls, Montevallo, Alabama, was found to have a chromosome number of 13. (2) Draparnaldia Isolate #2, an unidentified species obtained from Anniston, Alabama, was found to have a chromosome number of 13. (3) Draparnaldia acuta, Isolate #3 from Northwood Lake, Northport, Alabama, exhibited 26 chromosomes. (4) Draparnaldia plumosa strain 423 (Indiana Culture Collection), 418/a (Cambridge) was observed to have a chromosome number of 13.     

CHROMOSOME NUMBERS AND EVOLUTION IN NORTH AMERICAN SPECIES OF LINUM

Among the North American species of Linum there are three basic chromosome numbers representing invasions from the Old World of three distinct evolutionary lines. N = 9 is found only in the blue-flowered group represented in North America by two species, L. lewisii and L. pratense which are closely related to and may be conspecific with the Old World L. perenne. The basic number for the yellow-flowered species is n = 18 which is characteristic of the Scabrella and Virginiana subgroups. The loss of chromosomes in the Neo-mexicana (n = 13) and Sulcata-Rigida (n = 15) subgroups suggests that the basic haploid number of 18 might be a polyploid derivative of an Old World ancestor with n = 9. The incidence of n = 9 among Old World species of Linum may indicate that this represents an ancestral condition. Linum catharticum has n = 8; this number and features of morphology and distribution suggest that it is not directly related to either the blue-flowered or yellow-flowered groups in North America but represents a separate introduction on this continent.     

金沙江干热河谷种子植物区系特征的初探

研究涉及金沙江云南境内的干热河谷和干暖河谷的种子植物区系。建立名录共920种,有野生植物748种。这748种,分属于111科,427属。427属的分布区类型的格局为：l－44,2—127,3—10,4—39,5—13,6—37,7—29,8—47,9—12,10—25,11—3,12—7,13—l,14—20,15—13．在748种中,三江（金沙江、元江、怒江）干热河谷共有的标志植物73种,金沙江的标志植物156种,它们是研究区系特征的基础。经分析,本区植物区系有以下特征：(1)属、种均以热带成分为主,热带属占66.58%,种的热带成分更多,均交错少数温带成分;(2)三江干热河谷共同标志植物中,多数是优势种或常见种,例如Heteropogon contortus, Bombax ceiba,Phyllanthus emblica,Euphorbia royleana,Tribulus terrestris等,地区特有成分则少,如Terminalia franchetii,Andropogon yunnanensis;(3)滇北、川西南河谷特有成分则较多,如Cycas panzhihuaensis,Nouelia insignis,Aristolochia delavayi等;(4)西南特有成分也较多,且在河谷常见,如Delavaya yunnanensis,Croton yunnanensis,Munronia delavayi等;(5)有一些非特有的特殊种类,如Heteropogon melanocarpus,Dinebra retroflexa等.鉴于特征分析,本区植物区系有以下几个更深层的特征:(1)热带起源与近代交错现象;(2)有古地中海区系的后裔;(3)与近代非洲与南亚区系有联系;(4)与华北区系有联系;(5)特有现象明显而成因复杂,等。     

CHROMOSOME NUMBERS OF SOME EAST AFRICAN GRASSES

Chromosome numbers of 133 collections of grasses belonging to 51 genera and 105 species are reported here for material from East Africa. These include first counts for 5 genera and 51 species. The basic chromsome number of x = 6 has been found in Sporobolus; x = 10 in Loudetia and x = 13 in Pentaschistis have been confirmed. It is pointed out that chromosomes of Eragrostis vary considerably in size. The genera Harpachne, Commelinidium, Acritochaete, Pseudechinolaena and Exotheca, which are cytologically examined for the first time, have chromosomes with the socalled “panicoid” features, viz., chromosomes with small size and x = 9 or 10.     

芦苇细胞培养中的染色体稳定性及诱变效应

培养一年后的芦苇愈伤组织中,仍以80%的八倍体细胞占绝对优势。染色体数目变异范围在105—26之间。而 EMS 处理的愈伤组织与末经处理的愈伤组织相比较,明显地具有比较高的染色体数目变异和倍性变异。     

两种蒿属植物的染色体数目和核型研究

本文报道了我国蒿属2个种的染色体核型,它们的核型模式为:油蒿2n=36=28m+6sm+2st;褐沙蒿2n=36=26m+2sm+8st(2SAT)。     

FORMATION AND DISSOCIATION OF CELL AGGREGATES IN SUSPENSION CULTURES OF PAUL'S SCARLET ROSE

In liquid culture stem tissue of Paul's Scarlet rose produces a suspension containing cell aggregates of extremely variable dimensions. There is, however, a definite pattern of change in the degree of cell aggregation over time. During the period of most rapid cell division large aggregates form as the result of a minimal separation of the proliferating cells. As the rate of cell division slows, the average number of cells per aggregate decreases. The dissociation of cell aggregates continues at a uniform rate after cell division has stopped. Cell separation is inhibited at low (0.1 mg/1) auxin (NAA) concentrations and by substitution of sucrose for glucose in the culture medium. Cell separation is delayed (but not greatly inhibited) by kinetin. The presence of casein hydrolysate prevents the formation of the large cell aggregates normally occurring in the early stages of the culture cycle. A variant strain which shows a much higher degree of cell separation has been isolated from stock callus tissue grown on solid medium.     

CHROMOSOME NUMBERS AND SOME MORPHOLOGICAL ATTRIBUTES OF VARIOUS SOUTH AFRICAN GRASSES

de Wet , J. M. J. (Div. Botany, Pretoria, So. Africa.) Chromosome numbers and some morphological attributes of various South African Grasses. Amer. Jour. Bot. 47(1): 44—49. Illus. 1960.– Chromosome numbers are reported for 68 species and varieties of grasses belonging to 40 genera. These include first reports for the genera Megastachya, Lintonia, Plagiochloa, Ctenium, Oropetium and Beckeropsis. Cytological data were correlated with observations from leaf and embryo anatomy. A common ancestor is postulated for the tribes Oryzeae, Ehrharteae and Centotheceae. The genera Lasiochloa, Plagiochloa and Urochlaena appear to belong neither with the tribe Festuceae nor with the Eragrosteae but probably are closer related to the Danthonieae. Lintonia. Entoplocamia, Tetrachne and Fingerhuthia are characterized by the chloridoid-eragrostoid type of cytology and leaf anatomy but the bambusoid type of embryo anatomy. For these reasons they appear to represent relics of the original Eragostoid and Chloridoid stock. The South African representatives of the genus Crinipes differ from the tropical species in respect to leaf anatomy. The tropical species are typically of the arundinoid type, whereas the South African species appear to be related to the Danthonieae.     

东北产20种植物染色体数目

东北产２０种植物染色体数目沙伟,王丽华,杨晓杰,戚晓丽,马革红,赵大勇（齐齐哈尔师范学院生物系齐齐哈尔１６１００６）关键词染色体数目,毛茛属,蒲公英属,鸢尾属,白屈菜属ＣＨＲＯＭＯＳＯＭＥＮＵＭＢＥＲＳＯＦ２０ＳＰＥＣＩＥＳＦＲＯＭＮＯＲＴＨＥＡＳＴ...     

长柄山蚂蝗属三个种的核型分析及山蚂蝗属两个种的染色体数

长柄山蚂蝗属Podocarpium(Benth.)Yang et Huang属蝶形花科,间断分布于东亚和中北美洲,广布种分布到非洲和大洋洲。北美有4种,亚洲约有14种.我国约有该属植物11种,以西南和长江以南地区分布种类最多。国外已有人做过本属一半以上的种的染色体记数和核型。本文对本属的三个种.长柄山蚂蝗P.podocarpum(DC.)Yang et Huang,大苞长柄山蚂蝗P.williamsii(Pamp.)Yang et Huang和云南长柄山吗蝗P.du-clouxii(Pamp.)Yang et Huang进行了染色体的记数和核型描述,其中后两个种的工作属于首次。此外,本文还首次报道了山蚂蝗属两个种:Des-modium caudatum(Thunb.)DC.和D.yunnanense Franch.的染色体数目。     

两种珍珠菜属植物染色体数目及核型的观察

狼尾花(Lysimachia barystachys Bunge)和腺药珍珠菜(L. stenosepala Hemsl.)是珍珠菜属(Lysimachia)的两种植物。该属植物全世界约有180种,我国有120种左右。截止目前,本属植物中已作过染色体计数的种类不多,尤其在国内有文献报道的更是屈指可数,仅见庄灿旸等关于滨海珍珠菜(L. mauritiana Lam.)的报道。因     

CHROMOSOME NUMBERS IN SINGLE CELL CLONES OF TOBACCO TISSUE

Two clones of tissue of single-cell origin isolated from crown gall callus of Nicotiana tabacum were examined cytologically. Both clones had been grown on the same medium under the same conditions for 8 years. Chromosome counts of 110 polar views of metaphase plates revealed chromosome numbers of 48, 96, and 192 in both clones, the majority having 48. The nucleus of the original cell from which each clone was grown must have possessed 48 chromosomes. The polyploidy which developed may be ascribed to wounding, to the constituents of the culture medium, and/or to abnormal mitoses.