Karyological studies on Indian spiders

The diploid set of chromosomes inPalystes whiteae Pocock (Eusparassidae),Selenops montigenus Simon (Selenopidae) andTarrocanus viridis Dyal (Thomisidae) is constituted by forty-three, twenty-nine and twenty-seven acrocentric elements respectively. The males of all these three species have a sex-determining mechanism of the XXXO-type. The autosomes ofP. whiteae andT. viridis are simple rods, more or less pointed at one end, while inS. montigenus they carry terminal knobs. The sex-chromosomes which are unequal, move to one pole of the spindle precociously, during anaphase I.     

Karyological studies on some Antarctic liverworts

Abstract

Chromosome counts are reported from five species of Antarctic hepatics belonging to five genera and four families. The chromosome numbers in the genera Herzogobryum (H. teres n = 9) and Paehyglossa (P. dissitifolia n = 9) are reported for the first time. The first chromosome count from Lophozia excisa, n = 27, is the highest reported from Lophozia. A diploid number, n = 18, is reported for the first time from Barbilophozia hateheri; a second count, n = 9, agrees with earlier reports. The commonest Antarctic liverwort Cephaloziella cf. exili[lora has n = 18 and this agrees with earlier reports for the genus.     

Karyological studies in Hyoscyamus species of Iran

Karyological studies were performed on Hyoscyamus species of Iran. The species studied showed variation with regard to chromosome number and details of karyotype. Two different basic chromosome numbers of x=14 and 17 were recorded for the genus corresponding to the two subgenera of Hyoscyamus . Chromosome numbers of six species are reported for the first time.     

Karyological studies in Jaborosa (Solanaceae)

Sixteen species of Jaborosa (Solanaceae), including eight endemic to Argentina, were studied karyologically. The numbers n  = 12 and/or 2n  = 24 were found in all species, the majority of the cases being new reports. Mitotic chromosomes were small- to medium-sized, the average length varying from 2.95 to 4.93 µm. All species had one to three chromosome pairs with satellites. The karyotypes, obtained for 13 species, were slightly asymmetrical: A ₁ ranged from 0.228 to 0.483, A ₂ ranged from 0.095 to 0.182, and Paszko's asymmetry index ranged from 0.84 to 3.47. In all species, metacentric chromosomes were the most common, followed by submetacentrics, but subtelocentrics were rare. Morphological similarities and sectional arrangements were not reflected in either a principal components analysis plot or asymmetry index plot, but the species could be singled out by their karyotype formulae and the different karyotype parameters taken. In Jaborosa , a notably diversified genus, exo-morphological evolution has taken place, together with evident chromosome rearrangements, whose disposition is different and not as clear as in related genera.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 467–478.     

Karyological studies of four genera of theChloranthaceae

Karyological observations on 7 species and 2 varieties of 4 genera belonging to theChloranthaceae demonstrate the presence of three basic chromosome numbers within the family, i.e., x = 8 (Hedyosmum), 13 (Ascarina) and 15 (Chloranthus, Sarcandra). The karyomorphology ofChloranthus andAscarina is similar, whereasSarcandra andHedyosmum display unique characteristics. Both karyological aspects, i.e., chromosome number and karyomorphology, demonstrate remarkable diversity ofChloranthaceae and complex relationships between its genera. A distant affinity betweenChloranthaceae andPiperales is suggested.Presented at the XV International Botanical Congress Yokohama 1993, Symposium on Relationships and Evolution of Primitive Angiosperms: Multidisciplinary Approaches.     

Karyological studies of some species of the Mongolian flora

The paper gives the chromosome numbers for 38 species of the Mongolian Flora. Some of the counts appear to be the first findings for the species. They are:Allium anisopodium 2n = 16, Caltha membranacea 2n = 32, Carex macroura 2n = 50, Carex redowskiana 2n = 26, Gastrolychnis brachypetala 2n = 72, Iris biglumis 2n = 40, Iris flavissima 2n = 28 andVicia multicaulis 2n = 24.     

Karyological studies inCoris julis (Pisces,Labridae)

In the present investigation the diploid number 2n=48 (NF=58) has been determined for females, primary males, and secondary males ofCoris julis from the Gulf of Palermo. Differentiated sex chromosomes have not been observed in the population under study.     

Karyological studies on Spanish Boraginaceae. V: Onostna L., Cerinthe L. And Alkanna Tausch (Lithospermeae)

The karyological survey of the Spanish taxa of Lithospermeae is completed with studies of OnosmaL., Cerinthe L. And Alkanna Tausch. The chromosome number of O. Tricerosperma Lag.subsp. tricerosperma is reported for the first time and those of C.gymnandra Gasparr. And A. Tinctoria (L.) Tausch have been counted for the first time in Spanish material.
Con este trabajo se completa el estudio cariologico de los taxones espanoles de Lithospermeae. Se estudian los correspondientes a OnosmaL., CerintheL. y Alkanna Tausch, de ellos, el niimero cromosomico de 0. Tricerosperma Lag.subsp. tricerosperma se indica por primera vez y los de C.gymnandra Gasparr.y A. Tinctoria (L.) Tausch corresponden al primer recuento con material espanol.     

Karyological studies of Japanese ants (Hymenoptera,Formicidae)

The karyotypes of nine Japanese ants in three subfamilies (Ponerinae, Formicinae, and Myrmicinae) were successfully analysed by the improved squash technique. Three ponerine species had 2n=7 and n=4 (Ponera scabra), 2n=22 (Brachyponera sinensis), and 2n=28 and n=14 (Cryptopone sauteri). Four formicine species had 2n=18 and n=9 (Camponotus sp. and C. tokioensis), 2n=26 and n=13 (Camponotus japonicus), and 2n=30 and n=15 (Lasius niger). Two myrmicine species had 2n=18 and n=9 (Leptothorax congruus), and 2n=37, 38, 39, and n=17, 18, 19, 20 (Pheidole nodus). It was found that the variation of chromosome number observed in P. nodus was caused by Robertsonian type polymorphism.     

Karyological studies on fifteen forms of amphisbaenians (Amphisbaenia-Reptilia)

The chromosome constitutions of 15 forms (2 acrodonts and 13 pleurodonts) of amphisbaenians belonging to two families and eight genera were studied. The diploid chromosome numbers varied from 30 to 44 with the number of chromosome arms (FN) ranging from 42 to 60. The karyotypes of 12 forms all contained 6 pairs of macrochromosomes with similar morphology and 9 to 12 pairs of microchromosomes. The remaining three species had a higher diploid number (40–44) and a wide variation in chromosome morphology. Karyotype variations were found in the same family, even in the same genus. The lengths of the 6 pairs of macrochromosomes in 5 of the 12 forms were measured and compared. This disclosed similarities in the mean lengths, relative lengths, and arm ratios of those forms. — Chromosome patterns found in the present study support, in general, the classification of amphisbaenians derived from analysis of morphological characters.Supported in part by United Health Foundation of Western N. Y. Research Grant G-66-RP-9, National Cancer Institute, CA-08737 and NSF GB 2460.     

Karyological studies onGentiana sect.Chondrophyllae (Gentianaceae) from China

Nineteen populations of fifteen species ofGentiana sect.Chondrophyllae from China were observed cytologically.Gentiana alsinoides, G. anisostemon, G. asterocalyx, G. exigua, G. heterostemon, G. intricata, G. praticola, G. pseudoaquatica, G. spathulifolia, andG. subintricata all had the same chromosome number of 2n = 20 (or n = 10), whereasG. piasezkii had 2n = 36,G. squarrosa 2n = 38,G. prattii 2n = 18,G. aristata 2n = 14 (n = 7), andG. heleonastes 2n = 12. All these chromosome numbers are documented here for the first time, except forG. squarrosa, where it is a new number report. The basic numbers of x = 6, x = 7 and x = 19 are new for the section. Karyotype analyses of some species revealed that, except for a few cases, the species examined mainly had metacentric chromosomes. 2n = 20 = 2m(SAT) + 18m was found to be the main type of karyotype for the species with 2n = 20. Chromosomal evolution and its mechanism in this section are also discussed.     

Karyological studies on Spanish Boraginaceae: Lithospermum L. sensu lato

LUQUE, T. & VALDÉS, B., 1984. Karyological studies on Spanish Boraginaceae: Lithospenum L. sensu lato . All of the Spanish taxa of Lithospermum L. sensu lato (Lithospermum sensu stricto, Neatostema, Buglossoides and Lithodora ), with the exception of Buglossoides gartonii (Bentham) I. M. Johnston, have been studied karyologically. The karyological characters allow the separation of three groups which do not correspond exactly with the morphological limits of the four genera actually recognized for Spain within Lithospermum sensu lato .
Se estudian cariológicamente los taxones españoles de Lithospermum L. sensu lato (Lithospennum sensu stricto, Neatostema, Buglossoides y Lithodora ), salvo Buglossoides gastonii (Bentham) I. M. Johnston. Por los caracteres cariológicos se pueden separar tres grupos cuyos límites no coinciden exactamente con los de los cuatro géneros actualrnente reconocidos para España dentro de Lithospcnum sensu lato .     

Karyological studies in someHypochoeris spp. (Compositae) from Sicily

FiveHypochoeris spp. from Sicily have been investigated:H. glabra L. (2n=10),H. radicata L. (2n=8),H. cretensis L. (2n=6),H. laevigata L. (2n=12),H. robertia Fiori (2n=8). Basic chromosome numbers are very variable, x = 3, 4, 5, 6. The karyotype of each species is presented. Geographical origin (S. America or Mediterranean region) of the genusHypochoeris and the taxonomic position ofH. robertia are discussed.     

Karyological and cytogenetic studies of conifers from West Siberia and Far East

The results summarize many years of karyological and cytogenetic studies of conifers from the boreal zone, done at the Sukachev Forest Institute. The species under study belong to four genera of the family Pinaceae: Larix (larch), Pinus (pine), Picea (spruce), and Abies (fir). Overall, the research covers more than 100 populations and habitats of the species from these genera. The study concerns species growing under both optimal and marginal conditions. The studies of the family Cupressaceae have been initiated. A special attention is given to conifers growing on bogs and in planted forests.     

Intra- and interspecific reproductive barriers inCrocus (Iridaceae)

The reproductive system was studied inCrocus genus (Iridaceae) following intra- and interspecific pollination, by using light and scanning electron microscopy. The results suggest that the stigma-style tract of theCrocus pistil is a mere promoter of pollen tube growth, while intra- and interspecific discrimination of compatible and incompatible pollen occurs in the ovarian tract. Here, the transmitting tissue consists of special epidermal cells, whose granular or floccular secretions provide the selective medium for the growth of pollen tubes. The ovarian self-incompatibility (SI) is widespread within the genus, resulting in a partial or complete suppression of self-fertilization. Moreover, postzygotic SI mechanisms, as well as postzygotic mechanisms of unknown nature, seem to be recurrent and both are responsible for seed abortion. The interspecific ovarian incompatibility concerns only unrelated crosses; crosses between related fertile species succeed both in fertilization and seed-set.