Search

Copyright of Zeitschrift für Sexualforschung is the property of Georg Thieme Verlag Stuttgart and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Morphological and cytological investigations as well as crossing experiments were carried out with Ranunculus seguieri Vill. and 4 species of the Ranunculus alpestris L. group ( R. alpestris L., R. traunfellneri Hoppe, R. bilobus Bertol., R. crenatus Waldst. & Kit.). For R. seguieri and R. alpestris, localities and distribution are given in addition to extensive diagnoses. A key to the species includes morphological characteristics and distribution data for R. traunfellneri, R. bilobus, and R. crenatus. New diagnostic characters are described. Crossing experiments between R. seguieri and the species of the R. alpestris group were unsuccessful. All 5 species have a chromosome number of 2 n = 16, the record for R. bilobus is new. There is no statistically significant difference between the karyotypes of R. seguieri and R. alpestris s. str. Nevertheless, according to morphological evidence and crossing experiments, R. seguieri is not closely related to the R. alpestris group. [ABSTRACT FROM AUTHOR]

The chromosome numbers of nearly all species of the grass subtribes Aristaveninae and Airinae from Europe and northern Africa are presented. Among the Aristaveninae the genus Aristavena has 2n = 14 chromosomes, whereas Deschampsia forms a polyploid series with the basic number x = 13. In the subtribe Airinae the basic number x = 7 predominates. Avenella includes a polyploid series up to dekaploidy, whilst the lowest diploid value so far known in grasses - caused by descending dysploidy - exists in the annual genera Airopsis and Periballia with 2n = 8. From both subtribes 12 different karyotypes are described and depicted as idiograms. The basic karyotypes of Corynephorus, Periballia and Vahlodea differ from each other by different chromosome length. SAT-chromosomes in the Airinae vary somewhat. Some marker chromosomes eludicate phylogenetic relationships. Amphiplasty appears in various genera and was studied particularly in the amphidiploid Aira caryophyllea. Karyological and genomatic trends are considered in relation to evolutionary strategies of annuals and perennials. The nuclear DNA content of some species has been determined cytophotometrically. In subtribe Airinae a positive correlation exists between chromosome volume, pollen diameter, and DNA content. A comparison of the duration of microsporogenesis and microgametogenesis in annual and perennial species with their nuclear DNA content has shown that a primary nucleotypic influence is not recognizable. [ABSTRACT FROM AUTHOR]

The karyology of 7 Onosma species is treated. Informations on the structure of the interphase nuclei and of the chromosomes in mitotic prophase, on chromosome numbers and on chromosome morphology are given; in some cases earlier chromosome counts are corrected. The chromosome numbers of O. inexspectatum Teppner, spec. nov. (2n = 14), O. rascheyanum Boiss. (2n = 30), O. sanguinolentum Vatke (2n = 30), O. albo-roseum Fisch. et C. A. Mey. (2n = 44) and O. giganteum Lam. (2n = 16) are reported for the first time. The earlier known number of 43 chromosomes in O. albo-roseum, found in most individuals from garden origin, is interpreted as monosomic (2n − 1 = 43). About 50% of the pollen grains contains the monosome, but this is eliminated at least in most cases in the EMCs. [ABSTRACT FROM AUTHOR]

The chromosome numbers of the 24 species of sect. Pelargonium were determined from field collected and cultivated plants of known localities in S. Africa. Twelve species are diploid (2n = 22), eight tetraploid (2n = 44), one hexaploid (2n = 66), and three octoploid (2n = 88). The chromosome numbers correlate well with the proposed subdivision of sect. Pelargonium. Its chromosomes are relatively small (1.0-1.5 µm) in comparison to most of the other sections, and its diploid karyotype is considered to be primitive. The occurrence of the basic number x = 11 in this section, in other sections of the genus, and in related genera ( Monsonia, Sarcocaulon) leads to the conclusion that x = 11 probably is basic for the whole genus. - The pollen meiosis, microsporogenesis and pollen fertility of the diploid species is normal, with the exception of one, possibly young taxon from the Greyton Nature Reserve. The tetraploid species could be of autoploid origin, the higher polyploids exhibit a mixed auto-alloploid nature. - The 20 diploid and tetraploid species have a relatively small distribution range, most of them occur in the SW. Cape Province of South Africa. This area may therefore be considered as the centre of origin of the genus. Three of the four high polyploid species occupy rather large areas. [ABSTRACT FROM AUTHOR]

Morphological and cytological investigations as well as crossing experiments were carried out with the 5 species of the Ranunculus alpestris group ( R. alpestris L., R. traunfellneri Hoppe, R. bilobus Bertol., R. crenatus Waldst. et Kit., R. magellensis Ten.). A key to the species is presented; localities and distribution are given in addition to extensive diagnoses. Crossing experiments between the 5 taxa were successful (F-F individuals, backcross types, tripeland quadrupelbastards); the morphology of the experimentally obtained F-hybrids was mostly intermediate. All 5 species as well as all hybrids have a chromosome number of 2n = 16; there is no statistically significant difference between the karyotypes of the 5 taxa. According to the results of the morphological investigations and the crossing experiments we can distinguish 2 subunits of very closely related species: a) R. alpestris, R. traunfellneri, R. bilobus; b) R. crenatus, R. magellensis. The speciation within the group of Ranunculus alpestris is discussed. [ABSTRACT FROM AUTHOR]