摘要:

Chromosome numbers for eight species ofImpatienshave been determined from herbarium specimens. The new counts for species are:

ISSN:0008-7114    

DOI:10.1080/00087114.1977.10796711

出版商:Taylor & Francis    

年代:1977

数据来源: Taylor

摘要:

Chromosome counts of all the Canadian taxa have been determined and their distribution maps are given. The hybrid nature ofM. x mediahas been established. Variational trends and reproductive biology of all the taxa have been studied. Two subspecies ofM. fistulosai.e. subsp.fistulosacomb. nov. and subsp.menthifoliacomb. nov. have been recognized to occur in Canada.

ISSN:0008-7114    

DOI:10.1080/00087114.1977.10796712

出版商:Taylor & Francis    

年代:1977

数据来源: Taylor

摘要:

Con questa ricerca si è confermato il numero aploiden= 6 per le specieCorella parallelogramma.Tra le varie specie del sottordine Phlebobranchiata già studiate sotto il profilo cariologia),C. parallelogrammaè unica per la forma e il comportamento dei bivalenti sperma- tocitari ed ovocitari. Non viene confermata a livello cariologico la parentela notata da altri autori fra le famiglie Corellidae ed Ascidiidae.

ISSN:0008-7114    

DOI:10.1080/00087114.1977.10796713

出版商:Taylor & Francis    

年代:1977

数据来源: Taylor

摘要:

The karyotype of the male ofAgama ruderatashows 46 elements which can be distingushed into 24 large rod-shaped subtelocentric and 22 small dot-shaped chromosomes. The karyotype of the female ofA. ruderatais very similar to that of the male. No heteromorphic chromosomes are observed either in the male or the female. Sex chromosomes are not identified. The fundamental chromosome number comes out to be 46.

ISSN:0008-7114    

DOI:10.1080/00087114.1977.10796714

出版商:Taylor & Francis    

年代:1977

数据来源: Taylor

摘要:

Comparative radioresistance of diploids and artificially raised tetraploids ofTrigonella foenum-graecumhas been investigated at 30 and 50 krad of gamma rays. Advantage of using autoploids for such studies have been discussed. Different parameters were taken into consideration. Germination in both cases show little effect of radiation. Despite higher ICV, at higher doses, 4nwere resistant in survival, growth reduction at maturity and pollen sterility. Seed setting in 4nwas severely affected. Differential response of 2nand 4nin chiasma frequency at different doses was noted. A possible correlation between higher frequency of abnormal cells, univalents, Lagging chromosomes, fragments in 4nwith higher ICV has been proposed.

ISSN:0008-7114    

DOI:10.1080/00087114.1977.10796715

出版商:Taylor & Francis    

年代:1977

数据来源: Taylor

摘要:

An interchange mosaic in a clone ofAloe barbadensisMill, is reported. The interchange has taken place between the two long non-homologous chromosomes, the L1and the L4. It is unequal and appears only in a few flower buds and root tips. The interchange probably occurred in the meristematic layer during the formation of a new sucker affecting both the root and the shoot system.

ISSN:0008-7114    

DOI:10.1080/00087114.1977.10796716

出版商:Taylor & Francis    

年代:1977

数据来源: Taylor

摘要:

The consistent presence of 2n= 24 chromosomes in 12 homologous pairs from root tip cells and of 12 IIs in pollen mother cells without any disjunctional anomalies indicate thatGalphimia gracilisis probably a basic diploid (x = 12). The somatic chromosomes ranged in length from 5.12 to 9.48 μ. The frequency of proximal chiasmata was high (87.5%) and the mean chiasma frequency/II was 1.76 ± 0.05.

ISSN:0008-7114    

DOI:10.1080/00087114.1977.10796717

出版商:Taylor & Francis    

年代:1977

数据来源: Taylor

摘要:

Pachytene chromosome morphology of the entire haploid complement ofP. philadelphicaLam. (n= 12) was studied. An idiogram was constructed based on chromosome length, lengths of chromatic and achromatic segments and the arm ratios. The twelve chromosomes were distinguishable from one another on the basis of these criteria. Chromosome eleven has the nucleolus organiser in the short arm. The present observations differ from those of GOTTSCHALK (1954) in some respects. Such differences are presumed to be due to the differences inherent in the genomes of the two populations studied.

ISSN:0008-7114    

DOI:10.1080/00087114.1977.10796718

出版商:Taylor & Francis    

年代:1977

数据来源: Taylor

摘要:

The nuclear number in the fusiform cambial initials, when analysed in fortnightly collections of cambial strips obtained from 20 year old trees ofPsidium guajavaL., has revealed that it varies from 1–5 in a cell, depending on the season. The multinucleate condition was observed more frequent in the dormant phase of the cambium than in its active form.

ISSN:0008-7114    

DOI:10.1080/00087114.1977.10796719

出版商:Taylor & Francis    

年代:1977

数据来源: Taylor

摘要:

Detailed karyotype studies were carried out on 24 agricultural strains ofCoriandrum sativum, which show similarity in their chromosome number (2n= 22) and morphology. Variation in somatic nuclei with 2n= 15, 23, 24, 25, 27 chromosomes have been observed. In C.sativumvar. W.B4, 2n—24 or extra 2 chromosomes have been noted in the somatic complement. The extra chromosomes are probably B chromosomes. The karyotype analysis together with meiotic studies, suggest that structural alteration of chromosomes have contributed to the evolution of the different strains within the species. The presence of supernumerary constrictions in duplicate indicates homozygosity for structural changes. The strains differ in relation to such changes as detected in karyotypes and formation of regular bivalents. These characters have been attained by selection and as such they are able to stand competition.

ISSN:0008-7114    

DOI:10.1080/00087114.1977.10796720

出版商:Taylor & Francis    

年代:1977

数据来源: Taylor