Comparative Analysis of Growth and Photosynthetic Characteristics of (Populus simonii × P. nigra) × (P. nigra × P. simonii) Hybrid Clones of Different Ploidides

To evaluate differences among poplar clones of various ploidies, 12 hybrid poplar clones (P. simonii × P. nigra) × (P. nigra × P. simonii) with different ploidies were used to study phenotypic variation in growth traits and photosynthetic characteristics. Analysis of variance showed remarkable differences for each of the investigated traits among these clones (P < 0.01). Coefficients of phenotypic variation (PCV) ranged from 2.38% to 56.71%, and repeatability ranged from 0.656 to 0.987. The Pn (photosynthetic rate) photosynthetic photon flux density (PPFD) curves of the 12 clones were S-shaped, but the Pn-ambient CO₂ (Ca) curves were shaped like an inverted “V”. The stomatal conductance (Gs)-PPFD and transpiration rate (Tr)-PPFD curves had an upward tendency; however, with increasing PFFD, the intercellular CO₂ concentration (Ci)-PPFD curves had a downward tendency in all of the clones. The Pn-PPFD and Pn-Ca curves followed the pattern of a quadratic equation. The average light saturation point and light compensation point of the triploid clones were the highest and lowest, respectively, among the three types of clones. For Pn-Ca curves, diploid clones had a higher average CO₂ saturation point and average CO₂ compensation point compared with triploid and tetraploid clones. Correlation analyses indicated that all investigated traits were strongly correlated with each other. In future studies, molecular methods should be used to analyze poplar clones of different ploidies to improve our understanding of the growth and development mechanisms of polyploidy.     

Isozyme evidence for the parentage and multiple origins ofPotamogeton ×suecicus (P. pectinatus ×P. filiformis,Potamogetonaceae)

Evidence from isozyme analyses indicates thatPotamogeton ×suecicus is the hybrid betweenP. pectinatus andP. filiformis. The hybrid appears to have arisen on several occasions. The isozyme profiles of this hybrid from the Rivers Wharfe and Ure in Yorkshire, south of the present limit of distribution ofP. filiformis, suggest that each population is a single clone; these clones may be relics from the Weichselian glacial period. Populations of the putative hybrid from the Rivers Tweed and Till are notP. ×suecicus but probably haveP. vaginatus andP. pectinatus as parents. If so, this is a remarkable example of a pondweed hybrid persisting vegetatively in an area outside the distributional range of one of its parents.     

Cytogenetical studies in the bridge cross Allium cepa× (A. fistulosum×A. roylei)

  Allium fistulosum harbours a number of desirable agronomical traits for the breeding of onions. However exploitation of A. fistulosum for onion breeding via direct sexual hybridization is problematic. Therefore, we examined if a bridge cross, using A. roylei as a bridging species, might provide an alternative. By means of genomic in situ hybridization (GISH) we showed that each of the three parental genomes can be distinguished from the others in interspecific hybrids, suggesting that these genomes contain sufficiently different repetitive DNA families. We succeeded in carrying out multi-colour GISH to metaphase spreads of a first-generation bridge-cross individual [A. cepa× (A. fistulosum×A. roylei], which is composed of three parental genomes. Recombination between the genomes of A. fistulosum and A. roylei took place to a large extent: 7 recombined chromosomes were observed, and it could be shown that the proximal regions of the recombined A. fistulosum/A. roylei chromosomes belonged to the former, whereas the distal parts belonged to the latter. The high percentage of bound bivalent arms in metaphase I of pollen mother cells of a fertile bridge-cross individual suggests the introgression of A. fistulosum genes, mediated by A. roylei, into the genome of A. cepa. However, the presence of univalents reflects decreased pairing and recombination between the three genomes. Pollen fertility and pollen-tube growth of the first-generation bridge-cross individual seem to be sufficient to produce a second generation bridge-cross (A. cepa×first-generation bridge cross) progeny. Received: 27 May 1997 / Accepted: 30 June 1997     

Molecular studies in Pelargonium (Geraniaceae). A taxonomic appraisal of section Ciconium and the origin of the ‘Zonal’ and ‘Ivy-leaved’ cultivars

An RFLP analysis of chloroplast and nuclear DNA was followed in this taxonomic appraisal of section Ciconium. The section appears to be a monophyletic one, which divides into two groups, or sub-sections. The Zonal Geranium, P. × hortorum is derived from section Ciconium, and the species most likely to be its ancestors are shown to be P. inquinans and P. zonale. Maternal inheritance of chloroplasts was demonstrated by comparing chloroplast DNA from interspecific hybrids with their parents. These data also suggest that P. inquinans was probably the maternal parent of P. × hortorum in the original crosses. The Ivy-leaved cultivars appear to be derived from P. peltatum, with some contribution from P. zonale and/or P. × hortorum.     

Karyological and serological studies in Rana lessonae,R. ridibunda and in their hybrid R. ‘esculenta’ (Amphibia,Anura)

The karyotypes of the three water frog forms: Rana lessonae, R. ridibunda and R. esculenta were analysed from bone marrow cell preparations of animals captured in several localities of the GDR. In the three forms chromosome morphology was similar (5 large and 8 small pairs), although differences in the relative length of most elements were found; R. esculenta chromosomes were always intermediate.One of the small pairs (Chr. 12) was found to be metacentric in R. lessonae and submetacentric in R. ridibunda. Most R. esculenta individuals examined had one meta-and one submetacentric 12th element, indicating the hybrid nature of this form. However 16.6% esculenta proved to be homozygous for either the metacentric or the submetacentric chromosome 12, while 13% lessonae individuals and 7.7% ridibunda were heterozygous for this element.By starch gel electrophoresis an analysis was undertaken of serum proteins from water frogs coming from regions in which the forms occur together (sympatric populations) and from zones in which only one of them lives (allopatric populations).In Rana lessonae, where only one allele had been previously described, two different alleles were found in animals coming from the GDR.If genetic polymorphism is excluded, between 6.1% and 9.1% individuals from sympatric lessonae and ridibunda populations showed introgression of an albumin allele. No gene introgression was found in allopatric lessonae populations from the Leningrad region or in ridibunda from Alma Ata and southern Bulgaria.     

Morphological and ecophysiological variation of the hybrid oak Quercus subpyrenaica (Q. faginea × Q. pubescens)

Natural hybridization is common among oaks. We studied the variability of morphological and ecophysiological variables in the hybrid Quercus subpyrenaica and its assumed parental species Q. faginea and Q. pubescens, which co-occur in NE Spain. To assess the fitness of these taxa we studied several ecophysiological variables (hydraulic conductivity, K_h; hydraulic specific conductivity, K_s; leaf specific conductivity, LSC; water potential corresponding to a 50% loss of conductivity, PLC₅₀; efficiency of light absorption, E_a). We performed a correspondence analysis (CA) to ordinate seedlings, grown under homogeneous environmental conditions, according to their plant and leaf morphology. The CA axis 1 synthesized intra-taxon variability, while the CA axis 2 summarized inter-taxa variability. Q. subpyrenaica showed a wide spectrum of forms, but they were overall closer to those of Q. faginea. We defined three phenotypes within the hybrid based on morphology, which were: (i) the robur group (Qs-r; auriculate leaf base, rounded lobe apex); (ii) Q. pubescens (Qs-p; rounded leaf base, acute lobe apex); and (iii) Q. faginea (Qs-f; acute leaf base, acute-spiny lobe apex). The mean values of K_s and PLC₅₀ arranged the hybrid groups in the same order as the ordination based on leaf morphology. The Qs-r group showed the highest values of K_s and PLC₅₀, while the Qs-f group showed the lowest. Both morphologically and ecophysiologically, the hybrids showed a wide range of values, which spanned and even exceeded the variation of parental taxa.     

The interspecific hybrid Petunia parodii × P. inflata and its relevance to somatic hybridization in the genus Petunia

Summary Attempts at the reciprocal cross between Petunia parodii and P. inflata using standard emasculation and pollination techniques failed. Limited pollen tube growth down the style in reciprocal crosses led to reproductive isolation between the self-compatible P. parodii and self-incompatible P. inflata. The interspecific hybrid was successfully produced by bud-pollination of P. parodii with P. inflata as the male parent in 22 percent of attempts, but not in the opposite direction. In vitro pollination of P. parodii ovaries with P. inflata pollen also produced hybrids. The small size of the ovary made it technically impossible to use P. inflata as the female parent for in vitro pollination. The interspecific hybrids were intermediate, as compared to the two parents, for six of the seven plant and flower characters measured. Furthermore, the hybrids had high pollen fertility, set abundant seed upon self-pollination, and readily inter-crossed with the parental species. The results are consistent with a high degree of chromosomal homology in the parental species and with minor genetic divergency leading to reproductive isolation that is pre-zygotic in nature. Overcoming the barriers to cross-incompatibility by practical techniques resulted in fertile interspecific hybrids that segregated for parental characters. The potential value of employing the parental species in somatic hybridization experiments is discussed.Michigan Agricultural Experiment Station Journal Article No. 8404     

Ontogeny of the digestive system and the profile of proteases in larvae of cachara (Pseudoplatystoma reticulatum Siluriformes: Pimelodidae) and its hybrid (Pseudoplatystoma corruscans × Pseudoplatystoma reticulatum)

The development of the digestive system and digestive proteases was studied in cachara (Pseudoplatystoma reticulatum) and its hybrid (P. reticulatum × Pseudoplatystoma corruscans) during the first 25 days after fertilization. Both groups presented a fast and similar development of the digestive system, and the unspecific alkaline protease profile suggested that the digestive capacity of hybrid larvae is higher than that of cachara after the last half of the studied phase. The activities of trypsin and chymotrypsin were similar and observed since the oocyte. These observations suggested that cachara and its hybrid has similar digestive capacity and digestive system development.     

Spectroscopic studies of metal complexes containing π-delocalized sulfur ligands. The pre-resonance Raman spectra of the antitumor agent 2-formylpyridine thiosemicarbazone and its Cu(II) and Zn(II) complexes

The pre-resonance Raman spectra of 2-formylpyridine thiosemicarbazone have been measured at three pH values corresponding to the fully protonated (H₂FPT⁺), half protonated (HFPT) and deprotonated (FPT⁻) forms of the ligand. Assignments of the vibrations coupled with the π→π^* transition have been made by comparison with the spectrum of the deuterated form (DFPT). The pre-resonance Raman spectra of the Zn(II) and Cu(II) complexes, [ZnFPT]⁺, [CuFPT]⁺ and [CuHFPT]²⁺, have also been measured. The spectral pattern of the Cu(II) complexes shows resonance enhancement of vibrations coupled with the π→π^*, as well as with the ligand to metal charge transfer transitions. In addition, it is consistent with coordination through thiolate sulfur in [CuFPT]⁺ and thione sulfur in [CuHFPT]²⁺.     

Monoamine Neurotransmitter Metabolites in the Cerebrospinal Fluid of a Group of Hybrid Baboons (Papio hamadryas × P. anubis)

Comparatively little is known about the pathways of proximate causation that link divergent genotypes, via neurophysiological differences, to distinct, species-specific social behaviors and systems. One approach to the problem compares gross activity levels of monoamine neurotransmitters (norepinephrine, dopamine, and serotonin), evidenced by their metabolites —3-methoxy-4-hydroxyphenylglycol (MHPG), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA), respectively— in cerebrospinal fluid (CSF). We have applied this method to Papio hamadryas and P. anubis, closely related baboon species with divergent social behavior, living in the Awash National Park (ANP), Ethiopia. We had previously shown that adult males of the two species differ in the ratio of HVA to 5-HIAA, and in concentrations of MHPG and HVA, but not 5-HIAA. Here, we compare monoamine metabolite levels of the parental species with those of 49 members of a naturally formed, multigenerational hamadryas × anubis hybrid group. We cage-trapped the baboons in July 1998, sampled their CSF by cisternal puncture, and assayed monoamine metabolites by high-performance liquid chromatography. Previous findings suggested, anomalously, that hybrid males showed the high 5-HIAA levels predicted by the low-serotonin–early-dispersal hypothesis (originally based on observation of rhesus macaques, Macaca mulatta), while hamadryas did not. The present study failed to find higher 5-HIAA levels in hybrids, resolving the anomaly, but leaving the previous result unexplained. Among adult females (underrepresented in our sample) and juveniles, metabolite levels of the hybrids did not differ significantly from either parental species. Overall, adult male hybrids resembled anubis in HVA and HVA/5-HIAA ratio, but did not show the low MHPG levels characteristic of that species. Consistent with a significant genetic influence on species differences in these metabolites, the adult hybrids showed intermediate means and greater intra-population diversity than the parental species for most variables, but showed no indication of hybrid dysgenesis in the form of low intermetabolite correlation. To the contrary, an enhanced HVA–MHPG correlation in the hybrids suggested a species-associated factor (not necessarily genetic) influencing both of these monoamine neurotransmitter systems.     

Chemical characterization (GC/MS and NMR Fingerprinting) and bioactivities of South-African Pelargonium capitatum (L.) L' Her. (Geraniaceae) essential oil

Chemical fingerprinting of commercial Pelargonium capitatum (Geraniaceae) essential oil samples of south African origin was performed by GC, GC/MS, and (13) C- and (1) H-NMR. Thirty-seven compounds were identified, among which citronellol (32.71%) and geraniol (19.58%) were the most abundant. NMR Spectra of characteristic chemicals were provided. Broad-spectrum bioactivity properties of the oil were evaluated and compared with those of commercial Thymus vulgaris essential oil with the aim to obtain a functional profile in terms of efficacy and safety. P. capitatum essential oil provides a good performance as antimicrobial, with particular efficacy against Candida albicans strains. Antifungal activity performed against dermatophyte and phytopathogen strains revealed the latter as more sensitive, while antibacterial activity was not remarkable against both Gram-positive and Gram-negative bacteria. P. capitatum oil provided a lower antioxidant activity (IC(50) ) than that expressed by thyme essential oil, both in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and β-carotene bleaching tests. Results in photochemiluminescence (PCL) assay were negligible. To test the safety aspects of P. capitatum essential oil, mutagenic and toxicity properties were assayed by Ames test, with and without metabolic activation. Possible efficacy of P. capitatum essential oil as mutagenic protective agent against NaN(3) , 2-nitrofluorene, and 2-aminoanthracene was also assayed, providing interesting and significant antigenotoxic properties.     

Social System of a Hybrid Baboon Group (Papio anubis × P. hamadryas)

We describe the social organization, mating system, and social structure of a group of hybrid baboons (Papio anubis×P. hamadryas) in Ethiopia's Awash National Park. The group contained elements of both hamadryas and anubis societies. Overall, the group was a multimale, multifemale group that lacked cohesion and frequently formed subgroups. Subgroup formation was more strongly associated with predation risk than food availability. Although there were several hamadryas-like one-male units OMUs within the group, there was no evidence of a hamadryas multilevel society. Male and female members of OMUs were phenotypically more hamadryas-like than non-OMU individuals. The group contained substantial variation in the strength of inter- and intrasexual bonds: some females primarily groomed males while other females primarily groomed females, and the patterns were consistent with the OMU substructure. Despite some promiscuous mating, mating was biased towards the hamadryas condition for all group members. Additionally, rates of immigration and emigration were very low, and mean pairwise relatedness within the group is rising. For measures of intersexual bonding, all members of the group were intermediate between anubis and hamadryas individuals in less hybridized groups. The group was phenotypically and behaviorally more intermediate than it was in the 1970s (Sugawara, K. (1988). Primates 29: 429–448.) and the changes may indicate a relatively young and dynamic hybrid zone.     

Volatile constituents of Erodium cicutarium (L.) L’ Hérit. (Geraniaceae)

Essential oils from Erodium cicutarium were obtained by hydrodistillation (samples consisting of entire plants (ec1), leaves and stems (ec2)) and analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS), resulting in a total of 177 components being identified. The essential oils were of a very similar chemical composition and consisted mainly of aliphatic compounds and their derivatives. Fatty acids and fatty acid derived compounds were the most common, 51.3% (ec1) and 60.1% (ec2), followed by carotenoid derived compounds, 12.6% (ec1) and 20.2% (ec2), and then terpenoids, 14.9% (ec1) and 14.2% (ec2). The main constituents in the oils were hexadecanoic acid, 22.8% (ec2) and 35.9% (ec1) and hexahydrofarnesyl acetone, 10.8% (ec2) and 11.6% (ec1). The results obtained differ markedly from those previously reported for the same species.     

Somatic embryogenesis of Pinus rigida?×?P. taeda and the relationship between the initiation of embryogenic tissue and zygotic embryo development

The pitch-loblolly pine hybrid (Pinus rigida × P. taeda) has useful characteristics of the parents, but its exploitation is hindered by restrictions of conventional breeding and propagation methods. This study was undertaken to establish an effective in vitro system for propagating pitch-loblolly hybrid pine through somatic embryogenesis and to unravel the relationship between the efficiency of embryogenic tissue initiation and zygotic embryo development. To initiate embryogenic tissue, megagametophytes of developing seeds were used as explants. Seeds were collected weekly, examined, and tested during June and July 2004. The medium and seed collection date were the most important factors for the successful somatic embryogenesis of P. rigida × P. taeda. Five embryogenic lines were obtained using a modified P. taeda basal medium, and the highest initiation rate was 0.55%, for seeds collected in 2 weeks, between July 3 and 16. Histological observation revealed that zygotic embryos of those seeds were mostly at the proembryonic stage or in transition to precotyledonary stages. For the successful maturation of somatic embryos, abscisic acid and gellan gum were needed in the medium. The results show that, although further tests and development are required, somatic embryogenesis could provide a viable option for propagating P. rigida × P. taeda hybrids.     

Transformation of Montmorency sour cherry (Prunus cerasus L.) and Gisela 6 (P. cerasus × P. canescens) cherry rootstock mediated by Agrobacterium tumefaciens

Sour cherry (Prunus cerasus L.) scion cv. Montmorency and rootstock cv. Gisela 6 (P. cerasus x P. canescens) were transformed using Agrobacterium tumefaciens strain EHA105:pBISN1 carrying the neomycin phosphotransferase gene (nptII) and an intron interrupted ss-glucuronidase (GUS) reporter gene (gusA). Whole leaf explants were co-cultivated with A. tumefaciens, and selection and regeneration of transformed cells and shoots of both cultivars was carried out for 12 weeks on selection medium containing 50 mg l(-1) kanamycin (Km) and 250 mg l(-1) timentin. These media were [Quoirin and Lepoivre (Acta Hortic 78:437-442, 1977)] supplemented with 0.5 mg l(-1) benzylaminopurine (BA) + 0.05 mg l(-1) indole-3-butyric acid (IBA), and woody plant medium [Lloyd and McCown (Proc Int Plant Prop Soc 30:421-427, 1980)] containing 2.0 mg l(-1) BA + 1.0 mg l(-1) IBA for cv. Montmorency and cv. Gisela 6, respectively. Seven out of 226 (3.1%) explants of cv. Montmorency and five out of 152 (3.9%) explants of cv. Gisela 6 produced 30/39 GUS- and PCR-positive shoots from the cut midribs via an intermediate callus. Southern analysis of the GUS- and PCR-positive transformants confirmed stable integration of the transgenes with 1-3 copy numbers in the genomes of seven lines of cv. Montmorency and five of cv. Gisela 6. The selected transformants have a normal phenotype in vitro.