摘要:

Mean number of chromocentres in the interphase nuclei has been studied in two inbred lines of radish(Raphanus sativusL. var.radicolaPersoon), their F1hybrid and the original population. The inbred lines showed a significantly higher mean of chromocentres in the interphase nuclei than the original population, suggesting more heterochromatinization in the former. Mean number of chromocentres in the nuclei is restored in the plants of F1interlinear hybrid. A genotypic control of chromocentres has been proposed in radish.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796630

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

Individuals ofEutettix apricus(Melich), collected from nature, were found to possess multivalents in the spermotocytes—a rare phenomenon for chromosomes wth « diffuse centromere ». Translocation or fusion may be the cause for such a structural abnormality. Morphology and behaviour of gonial and spermatocyte chromosomes ofE. apricushave been compared withPhrynomorphus (= Athysanus)spp.,P.(=A.)indicus(Dist.?),P. (=A.)fusconervosus(Motsch?),P.(=A.)lineaticollis(Dist.) andNephotettix bipunctatus(Fabr.)—its near relatives.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796631

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

En utilisant des anthères et des inflorescences excisées, j'ai étudié l'incorporation du tryptophane3H dans les protéines non histones au cours de la microsporogénèse chez leRhoeo discolor.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796632

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

Pelecanus onocrotalusL. has the diploid number 66 and the fundamental number 82, andPhalacrocorax pygmaeusthe diploid number 70 and fundamental number 72. The heterosomes Z are metacentric in both species and the W heterosomes are telocentric.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796633

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

Two distinct groups of inclusions are recognized in the stroma of developing chloroplasts of mesophyll cells of aTriticale.One group, identified as fibrillar-globular inclusions, was studied in a former work (OLIVEIRA 1975b) and it is included here for discussion purposes. The second group is represented by inclusions which by the nature, dimensions and enzyme sensitivity of their elements are ribosomal. These ribosomes are organized into helical arrangements of polysomes. Deviations from this basic type of organization occur, but such variants may be due to planes of sectioning of the polysomes. Beside theii structure, the present work discusses the possible significance of the presence of these polysomes in terms of their ability to perform protein synthesis.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796634

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

The fine structural localization of peroxidases, during ethylene-induced abscission, in flower pedicels ofNicotiana tabacumL. cv. Little Turkish has been investigated. Peroxidase activity has been cytochemically localized in the rough endoplasmic reticula of tobacco abscission zone tissue that had been fixed in glutaraldehyde and subsequently incubated in diaminobenzidine (DAB) medium with post-fixation in osmium tetroxide. Tissue pre-incubated in potassium cyanide, prior to incubation in DAB medium containing the inhibitor, demonstrates a marked reduction in the DAB staining reaction. However, tissue pre-incubated in aminotriazole (an inhibitor of catalase enzymatic activity), prior to incubation in DAB medium containing the inhibitor, does not show inhibition of the DAB staining reaction in the rough endoplasmic reticula. It is suggested that the rough endoplasmic reticula, induced in response to ethylene treatment, exhibits enhanced peroxidase activity.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796635

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

La bromodeossiuridina induce sui bivalenti spermatocitari diStyela plicatala formazione di zone eterocromatiche negative, costrizioni secondarie, rotture e aumento della adesività aspecifica tra cromosomi. Pertanto sembra che la bromodeossiuridina possa venir impiegata con successo nel bandeggiamento dei cromosomi di ascidiacei.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796636

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

Il decorso della spermatogenesi inStyela plicataappare peculiare in quanto non si sono osservate piastre cromosomiche ascrivibili alla metafase I ed è ancora incerto se i cromosomi a V qui descritti appartengano all'anafase I o alla seconda divisione meiotica.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796637

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

Sex chromosomes inOncopeltus fasciatusandPyrrhocoris apterusare heterochromatic and transcriptionally inactive in well-defined phases of development. InOncopeltus, which has the XX/XY type of sex determination, the Y-chromosome seems to be inactive in aE tissues. The X-chromosome is inactivated during the last spermatogonial division and remains so throughout spermatogenesis. The X-chromosome ofPyrrhocoris, which is of the XX/XO type of sex determination is inactive in the same stages as that ofOncopeltusand during an additional phase in early oogenesis. X inactivation in spermatogenesis is interpreted as a form of gross regulation of gene activity on the chromosomal level.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796638

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

The processes involved in vacuole development are studied in cells of the root cap ofTriticale.The endoplasmic reticulum participates in the phenomenon either by producing provacuoles, which fusing each other give origin to bigger vacuoles, or by isolating cytoplasmic territories which, after lysis of the segregated materials, are transformed into typical vacuoles.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796639

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor