摘要:

After open pollination aP. atrisanguineaplant with 2n= 84 (12 x) produced offspring with 2n= 56 and 2n= 74. Controlled crosses betweenP. atrisanguineaandP. ambigens(2n= 82) yielded hybrids with 2n= 70 and 2n= 72. All these plants were vigorous. Meiotic observations onP. ambigensandP. atrisanguineashowed that both had an irregular meiosis with variable numbers of bivalents, univalents and multivalents.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796735

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Plant protoplasts treated in the same way as lymphocytes in animal cytogenetics allowed to point out a chromosomes counting technique in tobacco tissue cultures (MOURAS 1975). The analysis of the factors important to develop this method (pretreatment, osmotic concentration and temperature of the cell-enzyme mixture) leads to an improvement of the method. Hence it becomes possible to consider its application in order to identify not only mitotic chromosomes of tobacco, for which a karyogram is presented (Fig. 1), but also those of species with which the squash technique has only given, till now, poor results:Prunus(Figs. 2 and 3) andCorylus.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796736

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

The chloroplasts of sieve parenchyma cells from leaf minor veins ofArum italicumMill. are characterized by the presence of elongated paracrystalline inclusions often of very large size (up to 18–20 μm and over). Some sections of these inclusions clearly give evidence of a periodical structure. The thylakoidal system of these chloroplasts is well developed; the stroma is full of ribosomes often united into polysomes, which are frequently found attached to the external surface of thylakoidal membranes. A close spatial relationship between chloroplasts and dictyosomes is observed.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796737

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor