296 research outputs found
Nuclear DNA and nucleotype effect
The meaning of C DNA amount for the organism, in this mainly retroelements constituting often over 50% of the genome, is surveyed. Content of nuclear DNA is of specific character but among plant species there occur some exceptions. There exists the variation among the biotypes of the same species on the score of this parameter. Genomes can vary in DNA amount even over 1000-fold in angiosperms. Some close related species vary even 30-fold on that score. In some cases less complex organisms posesses more DNA than high advanced ones. These cases were named the paradox C-value. There are different theories, which try to explain these fenomena
Chronological and thematic approach to services in polish specialist literature
In Polish works from the fields of geography of services one can rarely find attempts of holistic approaches to its achievements from various points of view, formulated opinions, or updated information on its achievements. This results, among other things, in lack of visible progress in theory, practice and methodology of research. This paper presents factors limiting the development of research into services and their influence on the specificity and character of studies in this field. The outlined limitations and special character of conducted research is the background to the main part of this paper, that is chronological and thematic presentation of the issue of Polish geography of services. The description of the issue was divided into four periods which have the following names: the beginnings of research into the service sector, with two sub-periods; systematic research into services; “the first period” of the transformation period and contemporary geography of services. The geography of services evolved from being perceived and described as a part of the geography of settlement/geography of cities to become a separate area within geographical research. The increasing interest in services led to increased number of publications. Changes in quantity were followed by “structural” changes. The services started to be analysed from the point of view of particular sections, divisions or classes, and not generally (as a sector). The main focus of the discussion is trade in a broad sense. At present the analysis of trade takes into account new research problems within its own field which are called new geography of trade. It is necessary to increase communication between services research teams in order to share information and experiences and undertake joint studie
Chromosome numbers in Aconitum sect : cammarum (Ranuncu - laceae) from the Carpathians
Chromosome numbers for four species and two nothospecies of the sect. Cammarumser.Variegata,ser.Toxicum, and nothoser.Toxigatain the Carpathians amount to 2n=16, and in one case to 2n=32. For thenothospecies:A.×
gayeri Starmühl. and A. × pawlowskii Mitka et Starmühl. chromosome numbers are given for the first time. According to the cytological evidence a new combination
Aconitum degenii subsp. degenii var.intermedium (Zapał.) Mitka [=A. hebegynum non DC.] is proposed
Diploid chromosome numbers in Hieracium and Pilosella (Asteraceae) from Macedonia and Montenegro
The authors report the first discovery of diploid populations of Hieracium naegelianum Panč. subsp. naegelianum and H. naegelianum subsp. ljubotenicum Behr & Zahn., and give the first chromosome counts for H. cernuum Friv., H. gymnocephalum Griseb. ex Pant., H. sparsum Friv., Pilosella pavichii (Heuff.) Holub and P. serbica (F. W. Schultz & Schultz-Bip.) Szeląg from Macedonia and/or Montenegro. A diploid chromosome count for Hieracium renatae Szeląg is confirmed based on material from the whole distribution range of the species. An emasculation experiment showed that all the analyzed diploid Hieracium taxa reproduce sexually
Chromosome numbers in Hieracium and Pilosella (Asteraceae) from Central and Southeastern Europe
Chromosome numbers of 46 Hieracium L. and Pilosella Vaill. taxa from Austria, Bulgaria, Czech Republic,
Macedonia, Montenegro, Poland, Romania, Serbia and Slovakia are presented. Chromosomes numbers are given
for the first time for Hieracium amphigenum Briq. 2n = 3x = 27, H. bohatschianum Zahn 2n = 4x = 36, H.
borbasii R. Uechtr. 2n = 4x = 36, H. cernuum Friv. 2n = 2x = 18, H. hazslinszkyi Pax 2n = 3x = 27, H. mirekii
Szeląg 2n = 4x = 36, H. polyphyllobasis (Nyár. & Zahn) Szeląg 2n = 3x = 27, H. porphyriticum A. Kern. 2n =
4x = 36, H. racemosum Waldst. & Kit. ex Willd. subsp. racemosum 2n = 3x = 27, H. scardicum Borm. & Zahn
2n = 4x = 36, H. sparsum subsp. ipekanum Rech. fil. & Zahn 2n = 4x = 36, H. sparsum subsp. peristeriense
Behr & Zahn, H. sparsum subsp. squarrosobracchiatum Behr & al. 2n = 3x = 27, H. tomosense Simk. 2n =
4x = 36, H. tubulare Nyár. 2n = 4x = 36, H. werneri Szeląg 2n = 3x = 27 and Pilosella fusca subsp. subpedunculata
(Zahn) Szeląg, as well as five species of Hieracium sect. Cernua R. Uechtr. not described to date and
a hybrid between H. bifidum s. lat. and H. pojoritense Woł
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