摘要:

The F1hybrid,S. xanthocarpumandS. melongena, was completely sterile despite a normal meiosis. Fertility was restored by chromosome doubling of the F1. Sterility is therefore attributed to cryptic structural hybridity.

ISSN:0008-7114    

DOI:10.1080/00087114.1971.10796434

出版商:Taylor & Francis    

年代:1971

数据来源: Taylor

摘要:

Cytological observations on 16 species (22 taxa and cytotypes) ofDiplaziumfrom various regions of the Himalayas, have been carried out. Out of these, as many as 3 species (5 taxa and cytotypes) are apogamous but incidence of polyploidy is rather low, only 18.2% and that too upto tetraploid level. Triploid apomicts are in abundance. A diploid sterile hybrid,D. polypodioides X asperumhas been detected in which monads and diads are frequently produced. It has also been noticed that the putative parents of triploid apogamousD. simpliciveniumcould be diploid apogamousD. stenochlamysand any of the diploid sexual forms ofD. latifoliumcomplex.

ISSN:0008-7114    

DOI:10.1080/00087114.1971.10796435

出版商:Taylor & Francis    

年代:1971

数据来源: Taylor

摘要:

A cytological study was accomplished on the immature metaxylem ofAllium ceparoots in the histological region between 500 and 3000 μ from the tip. Labelling experiments with3H-thymidine,3H-uridine and3H-lysine were also carried out.

ISSN:0008-7114    

DOI:10.1080/00087114.1971.10796436

出版商:Taylor & Francis    

年代:1971

数据来源: Taylor

摘要:

InHelix aspersaspermatocytes, the nucleolus can be observed throughout the first meiotic prophase, with a « natural segregation » between « pars fibrosa » and « pars granulosa ». It also shows a close relationship with the nuclear envelope.

ISSN:0008-7114    

DOI:10.1080/00087114.1971.10796437

出版商:Taylor & Francis    

年代:1971

数据来源: Taylor

摘要:

The karyotypes ofDolomys bogdanoviandGlis glishave beenstudied.It has been established that the populations of MARTINO'S SNOW VOLE from Central and Southern Yugoslavia, which greatly differ from one another by their external morphology and the morphology of teeth, do not reveal any differences in the shape of the chromosomes. The diploid number for all the populations of MARTINO'S SNOW VOLE is 2n= 54, while the fundamental number is 54. The complement consists of 25 acrocentric autosomes with more or less marked shorter arms, and one pair of small metacentric chromosomes. The X sex chromosome is a large subtelocentric, and the Y sex chromosome a small acrocentric element. There are no differences between the autosomes of the male and female animals. The analyses of the chromosome complement ofG. glisfrom Yugoslavia has shown that the diploid number is 2n= 62, while the fundamental number is 120. Most chromosomes are metacentric or metacentric with a median position of the centromere sensu stricto (classification according to LEVAN, FREDGA and SANDBERG 1964) and a smaller number of chromosomes have a submedian or subterminal centromere. One pair of autosomes is provided with two satellites. The X chromosome is a metacentric element of medium size, while the Y chromosome is a small punctiform element.

ISSN:0008-7114    

DOI:10.1080/00087114.1971.10796438

出版商:Taylor & Francis    

年代:1971

数据来源: Taylor

摘要:

Five desynaptic mutants isolated in M2confirmed in M3and cytologically analyzed in M4have been investigated. Two of these (DS1and DS2) were isolated in the cv. Cappelli after seed treatment with Ethylmethansulphonate (EMS), and thermal neutrons respectively. The other three (DS3, DS4and DS5) were isolated in the cv. Aziziah after seed treatment with thermal neutrons, EMS and fast neutrons, respectively.

ISSN:0008-7114    

DOI:10.1080/00087114.1971.10796439

出版商:Taylor & Francis    

年代:1971

数据来源: Taylor

摘要:

The chromosome morphology of 4 lines of tetraploid wheat was studied. No great differences were observed between the karyotypes ofT. araraticumandT. timopheevion one hand andT. dicoccoidesvar.nudiglumisand an accession collected in Turkey and attributed toT. dicoccoideson the other. Therefore, these two last lines can be considered to belong to theTriticum araraticum — timopheevicomplex. Consequently, this complex occupies a distribution area much broader than previously thought.

ISSN:0008-7114    

DOI:10.1080/00087114.1971.10796440

出版商:Taylor & Francis    

年代:1971

数据来源: Taylor

摘要:

In sowbane plants infected with sowbane mosaic virus (SOMV), virus particles were found in great amount in the mesophyll and xylem. They were present not only in the cytoplasm, but also in the vacuole of parenchyma cells and differentiating tracheids of minor veins. The tonoplast of virus-containing cells showed alterations, such as increased electron density and formation of convolutions bulging into the vacuole. Virus-containing cells were rich in peroxisomes and fat bodies.

ISSN:0008-7114    

DOI:10.1080/00087114.1971.10796441

出版商:Taylor & Francis    

年代:1971

数据来源: Taylor

摘要:

Karyotypes of nine species ofRattusfrom the mainland of South Vietnam and one from Thailand are presented. Members of the subgenusRattus, includingRattus argentiventer, Rattus exiguus, Rattus exulans concolor, Rattus nitidus, Rattus norvegicus, Rattus rattus molliculusandRattus sladeni, had diploid numbers of 42 and very similar karyotypes.Rattus surifer finisandRattus moi, both in the subgenusLenothrix, had identical diploid numbers, 52, but dissimilar karyotypes. The karyotype ofRattus sabanus revertensfrom South Vietnam was similar to that ofRattus sabanusreported from Malaysia.

ISSN:0008-7114    

DOI:10.1080/00087114.1971.10796442

出版商:Taylor & Francis    

年代:1971

数据来源: Taylor

摘要:

The modifications of the plastid structures in a Maize mutant, « golden-leaf », have been studied in the electron microscope. In this mutant plastid organization is temperature dependent. At 25°C the chloroplasts are quite regularly structured, but when the corn plants are transferred to 16°C, the plastids become incompletely organized or anomalous. If higher temperature conditions are re-established, the plastids are able to regain their original organization only if a prolamellar body or structured grana, even in an anomalous state, are present. When the plastids are affected by the lower temperature in a very young stage, their modifications become irreversible, and their appearance resembles, also in the regreened tissues, that of albino plastids or of chromoplasts.

ISSN:0008-7114    

DOI:10.1080/00087114.1971.10796443

出版商:Taylor & Francis    

年代:1971

数据来源: Taylor