摘要:

Urginea indica, collected from the coastal region of Cox's Bazar was found to have 2n= 2x = 20 chromosomes in each of the 60 plants studied. Karyotype analysis showed that the chromosomes were all acrocentric, and chromosome I instead of III (as reported by some workers), had a secondary constriction. The two pretreating substances, 8-Hydroxy- quinoline and colchicine had the same ability in contracting the chromosome.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796738

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

The pattern of chromatin condensation in the developing sperm nucleus of the scorpion,Centruroides vittatus, is described. The chromatin fibrils become especially distinct and remain well defined until quite late in spermiogenesis. The fibrils that compose the chromosomes are arranged in groups. The chromosomes in this species have diffuse kinetochores. The sperm head is helical in the swimming sperm and acquires this shape without the influence of microtubules, which are not present. Also absent is the centriole adjunct, though this organelle is found in other scorpions.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796739

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Nuclear volumes and the frequencies of nuclei of different shape classes were determined, in cells in interphase and in prophase, in meristems of young and old primary roots, of long lateral roots and of small primordia ofVicia faba.Protein content of isolated nuclei of lateral roots was also determined. Lateral roots were treated with 0.0002% colchicine for two hours and volumes of metaphase chromosome complements were determined. The parameters measured all showed considerable variation: 1) interphase nuclear volumes covered an 8-fold range in old primaries and a 14-fold range in lateral roots; 2) nuclear protein contents showed a 5-fold spread of values; 3) prophase nuclear volumes showed a 4 to 7-fold range of values; 4) chromosome volumes covered a 5-fold range. Nuclear volumes, in most cases, were significantly different from a linear or a log normal distribution. Nevertheless, these values, on probit plots, did not fall into discrete sub-populations and we were unable to distinguish between fast, slow and non-cycling cells on the basis of their nuclear volumes. This and the variability in nuclear volume, suggests that nuclear growth rates are not uniform in interphase. It was concluded that since nuclear volumes are so variable they cannot be used to estimate the age of a particular cell in the cell cycle. Meristematic cells are heterogeneous for cell cycle duration and for a number of nuclear parameters.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796740

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Transplant experiments with six selected contrasting morphological ‘variants’ ofPlantago lanceolataL. proved the hereditary nature of their intraspecific morphological variation. Cytological investigation of these ‘variants’ revealed no variation either in their meiotic behaviour or in their karyotypes. The diversity distinguishing the ‘variants’ has been suggested to be produced by simple genie differences.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796741

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Cell surface and endocellular polysaccharides of growing and differentiatedDictyostelium discoideumhave been isolated and characterized with electrophoretic and chromatographyc procedures.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796742

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Des nombres chromosomiques nouveaux sont rapportés pour les genres Trichomanes, Selenodesmium, Vandenboschia, Crepidomanes et Gonocormus. Dans le genre Microgonium, nous avions mis en évidence des complexes apomictiques aneuploïdes avec des nombres chromosomiques élevés. Dans les genres Vandenboschia et Gonocormus, certaines populations forment des complexes sexuels polyploïdes.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796743

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796744

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

The analysis of chromosome number and sex-determining system in fourteen species of chrysomelids belonging to four tribes of Chrysomelinae has shown a modal number of 2n= 24 chromosomes and Xypsex-system.Gastrophysa polygoni, Mesoplatys cincta(Phaedonini),Gonioctena nivosa, G. linnaeana, G. quinquepunctata(Phyllodectini),Chrysolina coerulans, C. bicolor, Oreina ganglbaueri (Chrysolinini),Paropsis reticulata, Paropsisternd octosignata, P. beataandChrysophtharta variicollis(Paropsini) have karyotypes of 24 chromosomes whileCyrtonus punctipennisand C. plumbeus (Phaedonini) have 28 chromosomes. In spite that the modal number of the Chrysomelinae seems to be 2n= 24, the most primitive number for the subfamily is probably 2n= 20, in agreement with the primitive number of Coleoptera Polyphaga. This number is only encountered in the ancestral genusTimarcha, being all the remaining numbers derived from the primitive one.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796745

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

A cytological analysis of the thelytokous speciesPsychoda parthenogeneticahas been made. A 3n=15 complement and a type of apomictic thelytoky have been found. Apart from the triploidy, the complement ofP. parthenogeneticais very similar to the one ofP. alternataandP. cinerea.The phylogenetic interrelationships with the related bisexual species P. severini and the origins both of the thelytoky and triploidy have been discussed.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796746

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Three different chromosome numbers, 2n= 10, 2n12 and 2n= 14 have been found in the wild populations ofVicia sativaof Israel. In both the 2n= 10 and 2n= 12 forms two different karyotypes were present but the 2n= 14 type apparently has a stable karyotype. The 2n= 10 types ofV. sativagrow mainly in man-made habitats while the 2n= 12 and 2n= 14 types are usually confined to primary habitats. Occasionally, plants having different chromosome numbers or karyotypes form mixed populations. No definite connection between chromosome types and taxonomic units could be established withinV. sativabut it is worth emphasising that only var.amphicarpahad 2n= 14. This vetch is unique also in bearing subterraneous pods and its chromosome complement is the shortest in the entire aggregate. These facts have been taken as an indication that var.amphicarpais an advanced form in theV. sativaaneuploid series.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796747

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor