Hybridisation,genomic constitution and generic delimitation inElymus s. l. (Poaceae: Triticeae)

Intergeneric crosses were made between representatives of the genomically-defined generaElymus, Agropyron, Elytrigia, Pseudoroegneria, andThinopyrum. The genomic constitution ofElytrigia repens, the type species ofElytrigia, is shown to be SSH, a genomic combination otherwise found only inElymus. The S genome ofPseudoroegneria has almost always a dominant influence on the morphology of the taxa of which it is a component.Wang (1989) showed that the J genome inThinopyrum and the S genome have considerable homoeology, with a mean c-value of 0.35 in diploid SJ hybrids. A genetic coherence from S to SJ^e, J^e, J^eJ^b, and J^b can be expected, agreeing with the continuous morphologic variation pattern observed. Because of the absence of morphological discontinuities between the taxa,Pseudoroegneria (S),Elymus (SH, SY, sometimes with additional genomes),Elytrigia (SSH, SSHX), andThinopyrum (SJ, SJJ, J) are best treated as a single genus,Elymus, following the generic concept ofMelderis in Flora Europaea and Flora of Turkey. The basic genomic constituents ofElymus will then be the S and/or J genomes.Agropyron, with diploids, tetraploids, and hexaploids based on the P genome is morphologically distinct from other genera inTriticeae. In a few species ofElymus andPseudoroegneria, a P genome is an additional constituent. In these cases the P genome has a negligible morphological influence. Therefore, it seems reasonable to maintainAgropyron as a separate genus.     

DNA evidence for multiple origins of intergeneric allopolyploids in annualMicroseris (Asteraceae)

Seventy populations of North American annualMicroseris, Stebbinsoseris, andUropappus species were examined for chloroplast and nuclear ribosomal DNA restriction site variability to determine the origin of the allotetraploid speciesS. heterocarpa andS. decipiens. Previously identified chloroplast DNA restriction site variants were used in concert with restriction site variation forNco I in the nuclear-encoded ribosomal DNA repeat. The presence of two, mutually exclusive restriction site gains were observed in diploid populations ofM. douglasii; these same variants were also found in populations of allotetraploidS. heterocarpa, indicating mutiple origins of this species from different maternal diploid populations ofM. douglasii. Variation in the rDNA repeat between the diploid annual species and the putative paternal genome ofU. lindleyi was found to be additive inS. heterocarpa. A similar relationship was observed for the origin ofS. decipiens; cpDNA restriction site variants found inM. bigelovii andM. douglasii were present inS. decipiens. The rDNANco I variants also were additive in this purported allotetraploid. These results confirm the reticulate evolutionary pattern inStebbinsoseris and provide another example of multiple origins of intergeneric allopolyploids.     

Preliminary analysis of numerical taxonomy of the genusSaguinus based on dental measurements

Although several investigations have been made from different viewpoints, the classification or interspecific relationships ofSaguinus still remain uncertain. In the present study, we applied multivariate analysis methods to dental measurements of part ofSaguinus populations of sufficient sample size and obtained the following conclusions.Saguinus can be classified into two main groups: one consists ofS. oedipus andS. leucopus, and the other ofS. fuscicollis, S. nigricollis, S. labiatus, andS. mystax. Concerning the former group, the two subspecies ofS. oedipus, S. o. oedipus, andS. o. geoffroyi, show a close affinity with each other and also a close relationship toS. leucopus, while the latter group consists of two subgroups of species, one includingS. fuscicollis andS. nigricollis, and the other includingS. labiatus andS. mystax. The biological distance betweenS. oedipus oedipus andS. o. geoffroyi is slightly larger than that between the pairs ofS. fuscicollis andS. nigricollis and ofS. labiatus andS. mystax. Factor analysis revealed significant factors which could explain the differences among the seven maleSaguinus populations. Taking all the results into account, it seems necessary to reconsider the phylogenetic relationships within the genusSaguinus.     

Biochemical diversity and genetic distance in two species of the genusSaguinus

A comparative study of 20 blood genetic systems was performed on three populations of genusSaguinus: S. fuscicollis weddelli, S. midas niger, andS. midas midas. Some markers are useful for the characterization of the two species.ADA ⁵, ADA⁶, CA2³, CA2⁴, andES2 ² occur only inS. fuscicollis whileADA ⁴is fixed inS. midas. S. midas midas showed heterozygosity value comparable to those previously obtained for the genusAlouatta. Estimates of genetic distance betweenS. fuscicollis andS. midas species of about 14% are in accordance with those referred to in the literature for interspecific differences. Genetic distances between subspecies ofSaguinus midas were nearly 3%, which is within the range for subspecies.     

Numerical analysis of the taxonomical status ofCallithrix kuhli based on measurements of the postcanine dentition

The postcanine dentition ofCallithrix geoffroyi, Callithrix penicillata, andCallithrix kuhli was compared metrically to determine whetherC. kuhli is a hybrid population ofC. geoffroyi andC. penicillata or not. Many measurements showed significant differences (p<0.01 orp<0.05) among the three marmosets. The dental variability inC. kuhli was not greater than those inC. geoffroyi andC. penicillata. Based on canonical analysis, the three marmosets are discriminated, andC. kuhli did not occupy a middle position betweenC. geoffroyi andC. penicillata on the first two canonical axes. In the projection of the first two principal components,C. penicillata tended to be distinguished fromC. geoffroyi andC. kuhli, andC. kuhli does not exhibit intermediacy betweenC. geoffroyi andC. penicillata. The present statistical analysis failed to provide evidence thatC. kuhli constitutes a population hybridized fromC. geoffroyi andC. penicillata, although the three marmosets were discriminated from each other. This may provide support for the hypothesis thatC. kuhli is not a hybrid population ofC. geoffroyi andC. penicillata but a distinct species.     

Do pollinators determine hybridization patterns in sympatricSatyrium (Orchidaceae) species?

The breakdown of species integrity was studied in three sympatricSatyrium (Orchidaceae) species at a site in the Western Cape province of South Africa. Hybrids with intermediate morphology were identified using multivariate analysis.Satyrium erectum ×S. bicorne andS. erectum ×S. coriifolium hybrids were common, while only oneS. bicorne ×S. coriifolium hybrid was found (a new record). Reciprocal artificial crossing experiments confirmed that genetic compatibility exists between all three species. However, the species have different pollinators: moths inS. bicorne, bees inS. erectum and sunbirds inS. coriifolium. Pollinators, rather than genetic factors, therefore, appear to be responsible for reproductive isolation between these species. Breakdown in pollinator specificity results in interspecific pollen transfer and the formation of hybrids. Overlap in floral signals, including nocturnal scent in bothS. erectum andS. bicorne, and bright coloration in bothS. erectum andS. coriifolium, facilitates the formation of hybrids between these species pairs. The brown, scented flowers ofS. bicorne, on the other hand, share no obvious floral signals with the bright orange, unscented flowers ofS. coriifolium, accounting for the rarity of hybrids between this species pair. Differences in floral morphology also result in mechanical isolation between these two species. Since the three species are sympatric in a very small part of their geographic ranges, it is unlikely that avoidance of hybridization has been an important selective factor in the evolution of specialized pollination systems.     

Chromosome banding and genome size differentiation inProspero (Hyacinthaceae): Diploids

Prospero is a Mediterranean autumn-flowering genus ofHyacinthaceae commonly classified inScilla asS. autumnalis andS. obtusifolia. Extensive dysploid and polyploid variation has been reported. In the present study 77 diploid accessions from the western to the eastern part of the area of distribution, the major part being from continental Greece and Crete, have been analysed for karyotype structure and, in part, for genome size. Methods employed were acetocarmine staining, Giemsa C-banding, fluorochrome staining mainly with chromomycin A₃/DAPI, silver impregnation, and Feulgen densitometry. Banded idiograms were established with a computer assisted karyotype analysis procedure. Chromosome numbers were 2n = 8 inP. obtusifolium, and 2n = 12 and 14 inP. autumnale s. l. Dispensable euchromatic chromosome segments and different types of B chromosomes occurred. Among the cytotypes with 2n = 14 two karyotypes from Turkey differed from each other and from the rest in form, position of the nucleolar constriction, and in genome size. The remaining accessions were similar in karyotype shape but three levels of genome size could be discerned, the highest (1C = 7.50 pg) being found on the Iberian Peninsula, an intermediate one on Corsica and Malta, and the lowest (4.27 pg) in the Aegean. The karyotype with 2n = 12 had an intermediate genome size, and that ofP. obtusifolium a relatively low one. Heterochromatin amount was generally low, but some karyotypes showed characteristic banding patterns. The relationship between the chromosome complements with 2n = 14, 12 and 8 is discussed on the basis of idiograms and DNA amounts.The authors respectfully dedicate this papers to emer. o. Prof. Dr.Elisabeth Tschermak-Woess on the occasion of her 80th birthday.     

Studies in the morphology and systematics of berberidaceae

The floral vasculature in three allied genera,Plagiorhegma, Jeffersoria andAchyls is investigated, and the results are compared with those ofEpimedium andVancouveria which are related closely toPlagiorhegma andJeffersonia. The vasculature in the receptacle ofPlagiorhegma andJeffersonia is similar, but that ofAchlys is much simpler. Slightly different trace patterns are observed in the sepals ofPlagiorhegma andJeffersonia. InJeffersonia, the 3-trace condition leaving 2 or 3 gaps is most frequently observed, but inPlagiorhegma traces of a double nature leaving a single gap are more frequent. The traces to the innermost sepals, petals and stamens are usually of a double nature leaving a single gap in both genera. Regular division and fusion are not observed in the receptacular stele. The vascular differentiation between sepals and petals is more advanced inPlagiorhegma andJeffersonia than inEpimedium andVancouveria. InAchlys, the traces are all staminal and single throughout their course. Two parts recognized in the pistils ofPlagiorhegma, Jeffersonia andAchlys are traversed by independent vasculature. The comparisons of pistil morphology including vasculature ofPlagiorhegma, Jeffersonia, Achlys, Epimedium andVancouveria lead to the interpretation that the pistils are based on the same morphological plan. The probable evolutionary trend in pistil is then suggested in these five genera.     

Numerical analysis of sexual dimorphism inSaguinus dentition

Among New World monkeys, more or less sexual dimorphism exists in the dentition, especially in the Cebidae. On the other hand, the Callitrichidae includingSaguinus are said to be characterized by a broad lack of sexual dimorphism with the exception of the reproductive organs. In the present article, sexual dimorphism in the dentition of someSaguinus species was reconfirmed using univariate and multivariate analytical methods. The results of the analysis were as follows: (1) there is no sexual dimorphism in the canine tooth size, except for the upper canine ofS. geoffroyi and lower canine ofS. mystax; (2) the overall tooth size difference between males and females is slight or none inS. geoffroyi, S. leucopus, andS. fuscicollis, relatively small inS. oedipus andS. mystax, and rather larger inS. midas; (3) an overall difference in shape factor between both sexes exists in all species ofSaguinus to a greater or lesser extent; (4) although only slight sexual dimorphism is recognized in the canine tooth itself, sexual dimorphism does exist in some adjacent teeth of the canine in a few species; and (5) there are some interspecific differences in the magnitude of the sexual dimorphism of theSaguinus dentition and these differences are more evident in species inhabiting the peripheral regions of the distribution areas of this genus. Taking all the evidence obtained into account, the sexual dimorphism in theSaguinus dentition must be re-investigated in comparison with other genera of the Callitrichidae.     

Studies on some fungi isolated from the rhizosphere of tomato plants and the consequent prospect for the control of Verticillium wilt

Summary Biological control of Verticillium wilt disease with antagonistic micro-organisms was studied. Antagonism of some fungi, isolated from tomato rhizosphere, toVerticillium albo-atrum R & B. was observedin vitro. A clearly defined zone, in which the growth of the pathogen was inhibited, was observed withPenicillium spp. (includingPenicillium chrysogenum Thom) andFusarium culmorum (S.G. Sm) Sacc., whileTrichoderma viride pers. ex Fries,Gliocladium spp. andPenicillium vermiculatum Dangeard, suppressed the growth ofV. albo-atrum by penetrating, and overgrowing it. OnlyT. viride andP. vermiculatum culture filtrate added to the Dox's agar, reduced the radial growth ofV. alboatrum. Root-dip application of culture filtrates ofT. viride andP. chrysogenum was found to be most effective in controlling the disease, followed by other species ofPenicillium andGliocladium spp. WhileFusarium culmorum provided no control. Improvement of plant height and vigour with a better yield due to culture filtrate treatment occurred. Root-dip application of antagonistic fungal propagules (T. viride, P. chrysogenum) to tomato seedlings was also very effective in controlling wilt in tomato plants grown inV. albo-atrum infested soil. Dedicated to the memory of the late Prof. Ivor Isaac with whom I had the pleasure of working     

The karyotype of the Azumi shrew<Emphasis Type="Italic">Sorex hosonoi</Emphasis>

Karyotype ofSorex hosonoi Imaizumi, 1954 from Mt. Asama in central Honshu, Japan, were examined with conventional staining and G-banding using ASG methods. The diploid and fundamental autosomal arm numbers were 42 and 66, respectively. The autosomes consisted of seven metacentric, six submetacentric, and seven acrocentric pairs. The sex chromosomes were large-sized acrocentric X and small-sized subtelocentric Y. The relationship between the karyotypes ofS. hosonoi andS. shinto was explained by one pericentric inversion at the no. 5 ofS. hosonoi and the no. 9 ofS. shinto. A rearrangement inS. shinto-hosonoi differed from the rearrangements occurring on no. 5 ofS. shinto-caecutiens/unguiculatus.     

Nectar flow and pollinators' efficiency in two co-occurring species ofCapparis (Capparaceae) in Israel

Two closely related species ofCapparis, C. ovata andC. spinosa, which are exposed to the same pollination environment were studied. The nectar volume and concentration ofC. ovata are higher than inC. spinosa. Both species have similar pollination efficiency, but the relative contribution of each pollinator is different.C. ovata is pollinated mainly hy hawkmoths while the principal pollinators inC. spinosa are bees.     

Effects of the physiological state of five yeast species on H+-ATPase-related processes

Effects of starvation and glucose preincubation on membrane potential, ATPase-mediated acidification and glutamic acid transport were studied in yeast speciesSaccharomyces cerevisiae, Schizosaccharomyces pombe, Dipodascus magnusii, Lodderomyces elongisporus andRhodotorula gracilis. Themembrane potential was highest after preincubation with glucose in all species butL. elongisporus andR. gracilis. In all cases the membranes were depolarized in the presence of 20 mmol/L KCl and hyperpolarized with 50 μmol/L diethylstilbestrol (DES). Theextracellular acidification caused by addition of glucose was highest after preincubation with glucose in all cases except inR. gracilis where there was none. In all cases except inR. gracilis addition of KCl caused a marked increase in the acidification rate. Addition of DES with glucose caused a large decrease in rate inS. cerevisiae but had much less effect on the other species.Transport of glutamic acid was clearly increased after pretreatment with glucose inS. cerevisiae, S. pombe andD. magnusii (mainly due to enhanced synthesis of the carrier) but actually decreased inR. gracilis andL. elongisporus. Addition of DES had an inhibitory effect in all species but much more pronounced inS. cerevisiae andS. pombe than in others. In general, both the acidification and the transport of glutamate were enhanced after preincubation with glucose but much more so in the semianaerobic species, such asS. cerevisiae, than in the strict aerobes (R. gracilis) where the effect was occasionally negative. There was no relationship between the ATPase-mediated acidification and the membrane potential.     

Structure and genomic organization of centromeric repeats in<Emphasis Type="Italic"> Arabidopsis</Emphasis> species

Centromeric repetitive sequences were isolated from Arabidopsis halleri ssp. gemmifera and A. lyrata ssp. kawasakiana. Two novel repeat families isolated from A. gemmifera were designated pAge1 and pAge2. These repeats are 180 bp in length and are organized in a head-to-tail manner. They are similar to the pAL1 repeats of A. thaliana and the pAa units of A. arenosa. Both A. gemmifera and A. kawasakiana possess the pAa, pAge1 and pAge2 repeat families. Sequence comparisons of different centromeric repeats revealed that these families share a highly conserved region of approximately 50 bp. Within each of the four repeat families, two or three regions showed low levels of sequence variation. The average difference in nucleotide sequence was approximately 10% within families and 30% between families, which resulted in clear distinctions between families upon phylogenetic analysis. FISH analysis revealed that the localization patterns for the pAa, pAge1 and pAge2 families were chromosome specific in A. gemmifera and A. kawasakiana. In one pair of chromosomes in A. gemmifera, and three pairs of chromosomes in A. kawasakiana, two repeat families were present. The presence of three families of centromeric repeats in A. gemmifera and A. kawasakiana indicates that the first step toward homogenization of centromeric repeats occurred at the chromosome level.Communicated by W. R. McCombie     

Cytological characterization of heterochromatin and rDNA inPinus radiata andP. taeda

Fluorochrome C-banding ofPinus radiata andP. taeda metaphase chromosomes showed many pericentromeric DAPI bands and interstitial CMA bands inP. radiata, and centromeric and interstitial CMA bands inP. taeda. Giemsa C-band patterns differed between the species with centromeric bands inP. radiata but no consistent bands inP. taeda. A karyotype ofP. radiata was developed based on banding patterns that distinguished all but two of the 12 pairs of chromosomes. In situ hybridization (ISH) using probes for high-copy ribosomal DNA (rDNA) showed 10 pairs of 18S–25S sites and two pairs of 5S sites in both species. Most of the sites were interstitial or centromeric.     

Epizootiology of virus diseases in three lepidopterous insect species of alfalfa

Summary The incidence of virus infections in three lepidopterous insect species was studied from 1965 to 1968 in alfalfa fields in California. The insects were the alfalfa caterpillar,Colias eurytheme; the beet armyworm,Spodoptera exigua; and the alfalfa looper,Autographa californica. InC. eurytheme, the major virus was a nuclear polyhedrosis virus (NPV); inS. exigua, a granulosis virus (GV) and an NPV; inA. californica, a GV. Virus epizootics did not develop in very high densities ofC. eurytheme. Virus epizootics occurred in low host densities of the three insect species, especially in populations ofA. californica. The virus acted as a density-dependent factor in the regulation of the populations ofS. exigua andA. californica. Temperature, humidity and rainfall had no marked effect on the incidence of virus infections.     

Satellite DNA properties of the germ line limited DNA and the organization of the somatic genomes in the nematodesAscaris suum andParascaris equorum

During the early cleavage divisions in some Ascarids, parts of the chromosomes are eliminated from the somatic blastomeres (chromatin diminution, Boveri, 1887) while the chromosomes in the germ line cells maintain their integrity. To characterize the germ line and soma genome, DNA was isolated from gametes and embryonic somatic cells of two Ascarid species,Parascaris equorum var. univalens andAscaris suum. It was shown that the germ line limited DNAs of these species have the same density and almost identical reassociation kinetics: in CsCl the predominant component of the germ line limited DNA ofP. equorum andA. suum has the buoyant density of 1.697g/cm³, while soma DNA of both species bands at 1.700 g/cm³. InP. equorum there is a small additional germ line limited satellite DNA component with the density of 1.690 g/cm³, identical to that of mitochondrial DNA of both organisms. Comparison of the reassociation kinetics of germ line and soma DNA demonstrates for both species that the eliminated DNA sequences are highly repetitive. In contrast to these similarities between the germ line limited DNAs ofP. equorum andA. suum the analysis of their base composition revealed differences (40% guanine plus cytosine inP. equorum and 36% inA. suum). The only very fast reassociating DNA sequences which we could isolate from soma DNA was demonstrated to be foldback DNA. The reassociation kinetics of totalA. suum soma DNA was investigated by hydroxylapatite chromatography. Least squares analysis of the data revealed about 10% of intermediate repetitive DNA sequences. Their interspersion between single copy DNA sequences was analyzed by comparing the reassociation kinetics of DNA fragments 0.35 and 7.2 kilobases long. Thus the DNA sequence arrangement ofAscaris does not follow the short period interspersion pattern observed in most organism.     

Alkaloids of theSedum acre-group (Crassulaceae)

The 16 species of theSedum acre-group were investigated for the presence of alkaloids. They areS. acre ofS. ser.Acria, S. alpestre, S. annuum, S. apoleipon, S. borissovae, S. euxinum, S. grisebachii, S. laconicum, S. multiceps, S. sexangulare, S. tuberiferum, S. tuberosum, S. ursi, andS. urvillei ofS. ser.Alpestria, S. samium ofS. ser.Samia, andS. litoreum ofS. ser.Litorea. S. acre differs significantly from the other species. It contains sedamine, hydroxy sedamine, and a number of 2,6-disubstituted piperidine alkaloids. The leafy parts of the species ofS. ser.Alpestria, S. ser.Samia, andS. ser.Litorea contain 4 piperidine alkaloids which also occur inS. acre, and in addition 4 pyrrolidine alkaloids not present inS. acre. The composition of the alkaloid fraction agrees with the infrageneric classification (series) based on the hybridization patterns of the species (comparia).     

The 5S DNA units ofAcacia species (Mimosaceae)

The DNA sequence structure of 5S DNA units inAcacia species, including representatives from the three subgenera ofAcacia, have been determined. The data was interpreted to suggest that at least three lineages of 5S DNA sequences exist inAcacia and the proposal was made that the lineages be named5S Dna-1, 5S Dna-2, and5S Dna-3. The5S Dna-1 lineage was represented by units fromA. boliviana andA. bidwilli, the5S Dna-2 lineage by units fromA. melanoxylon, A. pycnantha, A. ulicifolia, A. boliviana, A. bidwillii, andA. albida, and the5S Dna-3 lineage by units fromA. bidwillii, A. boliviana, andA. senegal. Based on this interpretation of the sequence data, the Australian species of subg.Phyllodineae grouped together as a cluster, quite separate from the subgeneraAculeiferum andAcacia. As expected from the analyses of morphological characters, the 5S DNA units fromAcacia albida (syn.Faidherbia albida) were quite separate from the otherAcacia spp.     

New species and combinations in Sabazia (Heliantheae,Galinoginae)

The genusSabazia is expanded to include the genusTricarpha, Calea palmeri, and several newly described taxa,S. tridacoides var.tridacoides and var.latifolia, S. palmeri var.lancifolia, andS. longiradiata. Comparative studies of several morphological features suggest thatSabazia is most clearly related toSelloa andGalinsoga. Karyological data reinforce this observation: inSelloa andGalinsoga x = 8 whereas inSabazia x = 4 andn = 4, 8, 16, or 24. Several species ofCalea are very similar toSabazia in floral features and may be of close phyletic affinity, but most species ofCalea differ conspicuously, suggesting more remote relationships. Other taxa in the Galinsoginae apparently fairly closely allied toSabazia includeOteiza andTridax.