摘要:

A cytotaxonomic study in the Himalayan orchids was undertaken to delineate the evolutionary trends and to unravel problems of phylogeny and taxonomy. Cytological observations on 20 species from northwest Himalayan region are reported. On the basis of secondary association among bivalents and chromosome numbers in multiples, it has been suggested that all the species ofHabenariainvestigated by us were hexaploid. The formation of bivalent chains and occurrence of dicentric bridges and fragments inNeottia listeroideswere attributed respectively to translocations and inversions at meiosis. InEpipactis belleporine, in addition to four pollen grains in a tetrad, one to two « sporads» were noted. A high proportion of taxa investigated were found to be polyploid. A number of genera had species with aneuploid numbers.

ISSN:0008-7114    

DOI:10.1080/00087114.1970.10796368

出版商:Taylor & Francis    

年代:1970

数据来源: Taylor

摘要:

Tetraploids of mulberry were produced by the treatment of young seedlings with 0.4 and 0.6% colchicine solutions for different durations. Maximum number of tetraploids were obtained with 0.4% solution for 9 hours.

ISSN:0008-7114    

DOI:10.1080/00087114.1970.10796369

出版商:Taylor & Francis    

年代:1970

数据来源: Taylor

摘要:

Morphology and pairing behaviour of the pachytene chromosomes in a tetraploid race ofS. arundinaceumwas studied on a quantitative basis. The study showed the chromosomes to be differentiated and that the 10 basic types characteristic of the diploid grainSorghumscan be recognised in the tetraploid. In a total of 131 pachytene associations studied the frequency of exchanges vary from none to two in a given set of four pairing chromosomes. Further the exchanges appear to have been spread out all along the length of chromosomes. From the evidence obtained and the regular meiosis observed in the polyhaploid derivative of this plant it was suggested that the tetraploid understudy had an autoploid origin.

ISSN:0008-7114    

DOI:10.1080/00087114.1970.10796370

出版商:Taylor & Francis    

年代:1970

数据来源: Taylor

摘要:

The presence of lipids in nucleoli of roots ofVicia fabahave been confirmed in two ways, namely, (i) by cytochemical studies of sections from fixed and embedded roots, and of unfixed and fixed frozen sections, and (ii) by autoradiographic studies on the incorporation of ethan-l-ol-2-amine-2-14C hydrochloride and14C-choline chloride. These lipids appear to be, in part, phospholipids.

ISSN:0008-7114    

DOI:10.1080/00087114.1970.10796371

出版商:Taylor & Francis    

年代:1970

数据来源: Taylor

摘要:

InLecanidion caesalpinii, sexual reproduction is found to be of « retrogressive type», where no specified sex organs are involved in the origin of asci and initiation of the ascocarp. This is the first report of the occurrence of this pattern of sexuality in the order Hysteriales, and could be attributed to « spontaneous heterokaryosis ».

ISSN:0008-7114    

DOI:10.1080/00087114.1970.10796372

出版商:Taylor & Francis    

年代:1970

数据来源: Taylor

摘要:

We aimed at tracing the variations of the DNA content in mulberry polyploid forms with different chromosome sets. Both the extreme forms of 28 and 308 chromosomes and triploid and tetraploid forms which are intermediate in the chromosome number were chosen as the object of investigations.

ISSN:0008-7114    

DOI:10.1080/00087114.1970.10796373

出版商:Taylor & Francis    

年代:1970

数据来源: Taylor

摘要:

Two of the three investigated species ofAntidesmarevealed polyploidy. Two cytotypes, one diploid (n= 13), and other hexaploid (n= 39) were detected inA. acuminatum.Morphological differences exist in the two races as a possible result of polyploidy.A. buniusexhibitsn= 117 (18-ploid) which is probably the highest chromosome count in the Euphorbiaceae. All the species of the genus known chromosomally, are based on 13. WILLIS' (1966)' idea of splittingAntidesmafrom the Euphorbiaceae and putting it in the Stilaginaceae is opposed on the basis of base number.

ISSN:0008-7114    

DOI:10.1080/00087114.1970.10796374

出版商:Taylor & Francis    

年代:1970

数据来源: Taylor

摘要:

A simple corneal epithelial squash technique was used to establish the karyotype of the Australian King QuailExcalfactoria chinensisLinné. It was found that the female was the heterogametic sex, and that the sex determining mechanism was the ZZ-ZW type. The karyotype of this species was found to have morphological similarities to the published karyotype of the Japanese QuailCoturnix coturnix japonica, but with certain recognizable differences.

ISSN:0008-7114    

DOI:10.1080/00087114.1970.10796375

出版商:Taylor & Francis    

年代:1970

数据来源: Taylor

摘要:

The results are reported of cytochemical and autoradiographic analyses on root primordia and root apices ofMarsilea strigosa.

ISSN:0008-7114    

DOI:10.1080/00087114.1970.10796376

出版商:Taylor & Francis    

年代:1970

数据来源: Taylor

摘要:

Several trisomies of peas have been isolated in the progenies of mutants induced with physical and chemical mutagenic treatments. The mutants (variegated andchlorinamaculatatypes) are characterized by the presence of unstable dicentrics and rings, which, as a result of breakage-fusion-bridge cycles, give rise to mosaic leaf patterns.

ISSN:0008-7114    

DOI:10.1080/00087114.1970.10796377

出版商:Taylor & Francis    

年代:1970

数据来源: Taylor