Adventitious shoot formation from embryonic explants of red pine (Pinus resinosa)

Adventitious shoots were induced from excised embryos of Pinus resinosa Ait, on half-strength Le-Poivre (LP) medium containing 1–70 μ M N⁶-benzyladenine (BA). At lower concentrations of BA, only 2–3 shoot primordia (from as many as 22 formed per embryo) developed into shoots when subcultured onto medium containing 0.5% activated charcoal. Concentrations of 10 to 70 μ M of BA produced significantly higher numbers of shoot primordia and most of them developed into shoots. Ten to 17 day culture on medium containing 10–25 μ M BA proved optimal for maximum adventitious shoot production. Less than three days of incubation on the cytokinin medium did not stimulate the formation of adventitious shoots. Twenty-four day culture on the same medium produced several shoots, but most of them failed to develop normally and formed callus. Coconut milk (0.1–5% v/v) inhibited adventitious shoot formation. Using optimal conditions, seeds from 11 open-pollinated selected trees were compared to test for genetic differences in the potential to produce adventitious shoots from embryos. No significant differences were observed with regard to the shoots produced per embryo among the different seed collections. More than 200 plants produced through this technique were tested for variation in several isozymes by electrophoresis. No variations were observed.     

Evolutionary history of two allopatric Terricola species (Arvicolinae, Rodentia) from molecular, morphological, and palaeontological data

To investigate the phylogenetic and phylogeographical relationships of arvicolines, we use several Western European ground voles. More particularly, our study is focused on Microtus ( Terricola ) savii and M. ( T. ) pyrenaicus . These two allopatric species are usually considered as having originated from the same ancestor, possibly M . ( T. ) mariaclaudiae . We propose molecular and morphological approaches: nucleotidic data from the mitochondrial cytochrome b and 12S rRNA genes and global morphological analyses from the first lower molar. Four other Terricola species ( multiplex , lusitanicus , duodecimcostatus , subterraneus ) were added to the data set for both analyses, and two other vole species ( Clethrionomys glareolus and Chionomys nivalis ) as outgroup to the molecular analysis, and five fossil populations to the morphological one. Palaeontological data are also widely taken into account. Both molecular and morphological analyses indicate that intra- Terricola relationships reflect the present-day geographical distribution of our data set species. Our results show that M. ( T. ) savii and M. ( T. ) pyrenaicus are from separate speciation events leading to two different biogeographical groups, respectively the Alpine–Italian group and the French–Iberian group, the latter being much more homogeneous. These speciation events could be related to Quaternary climatic changes, which induced southward migration, leading first to M. ( T. ) savii and second to M. ( T. ) pyrenaicus . The classical hypothesis of a geographical speciation for these two taxa from M. ( T. ) mariaclaudiae is invalid. However, the morphological data suggest a potential phylogenetic relationship between M. ( T. ) mariaclaudiae (ancestor) and M. ( T. ) pyrenaicus (descendant).  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 309–323.     

Acoustic and Morphological Differentiation in the Frog Allobates femoralis: Relationships with the Upper Madeira River and Other Potential Geological Barriers

We studied patterns of call acoustics and external morphological differentiation in populations of the dart-poison frog Allobates femoralis occurring in forested areas along a 250-km stretch of the upper Madeira River, Brazil. Multivariate analyses of variance using principal components representing shared acoustic and morphological parameters distinguished three groups in relation to call structure and external morphology: (1) populations belonging to a two-note call morphotype; (2) populations with four-note calls inhabiting the left riverbank; and (3) populations with four-note calls inhabiting the right riverbank. Our results report a case of Amazonian anuran diversity hidden by current taxonomy and provide evidence for the upper Madeira River being a boundary between distinct populations of A. femoralis , and suggest a new taxonomic interpretation for these groups. Samples that did not fit into the general differentiation pattern and the existence of a well-defined contact zone between two morphotypes on the left riverbank indicate that mechanisms complementary to river-barrier hypotheses are necessary to explain the phenotypic differentiation between populations. Our study shows that at least one anuran species shows congruence between population differentiation and separation by a large Amazonian river, as documented for birds and mammals. Conservation efforts should not consider the taxon now known as A. femoralis as a homogeneous entity. There is much within-taxon variability, which can be probably explained partly by the existence of cryptic species, partly by geological barriers and part of which currently has no obvious explanation.     

The deflecting wrinkle on the teeth of Icelanders and the Mongoloid dental complex

Three local populations from Northeast Iceland are surveyed for the occurrence of the deflecting wrinkle of the metaconid on second deciduous and first permanent lower molars. The trait occurs more frequently on dm2 than on M1, and no sexual dimorphism is found, as expected. However, the frequencies are clearly within those predicted by the Mongoloid dental complex for Mongoloid populations. It is therefore suggested that the inclusion of the deflecting wrinkle in the Mongoloid dental complex be re-evaluated, and the racial diagnostic value of the trait taken with reservation.     

CHARACTER DISCRIMINATORY POWER,CHARACTER-SET CONGRUENCE,AND THE CLASSIFICATION OF INDIVIDUALS FROM HYBRID ZONES: AN EXAMPLE USING STONE CRABS (MENIPPE)

Many investigators categorize individuals from hybrid zones to facilitate comparisons among genotypic classes (e.g., parental, F₁, backcross) for comparative studies in which components of fitness or geographic variation are being analyzed. Frequently, multiple character sets representing genetically independent traits are used to classify these individuals and various methodologies are employed to combine the classifications obtained from the different character sets. We adapted the principles of total evidence and taxonomic congruence (two formalized approaches used by systematists in formulating phylogenetic hypotheses) to address the problem of discriminating hybridizing species and classifying individuals from hybrid zones. As our model, we used two morphological (coloration and morphometric) and two molecular (allozyme and mitochondrial DNA restriction-fragment-length polymorphism) character sets that differentiate two stone crab species (Menippe adina and M. mercenaria). Using principal-components analysis, we determined that combining character sets and eliminating characters or character sets that did not have large eigenvector coefficients for the principal component that best separated the two species yielded the highest level of discrimination between species and allowed us to classify a broad range of morpho-genotypes as hybrids. For the stone crabs, three diagnostic allozyme loci and five diagnostic coloration characters best separated the species. The two character sets were not completely congruent, but they agreed in their classification of 50% of the individuals from the hybrid zone and rarely strongly disagreed in their classifications. Classification discrepancies between the two character sets probably represent variation between traits in interspecific gene flow rather than intraspecific, ecologically mediated variation. Our results support the assertions of previous investigators who espoused the benefits associated with using multiple character sets to classify individuals from hybrid zones and demonstrate that, if character sets are reasonably congruent and numerically balanced, combining diagnostic characters from multiple character sets (a total-evidence approach) can enhance discriminatory power between species and facilitate the assignment of hybrid-zone individuals to genotypic classes. On the contrary, classifying hybrid-zone individuals using character sets separately (a taxonomic-congruence approach) provides the opportunity to compare levels of introgression between species and to assess reasons for discordance among the data sets.     

Adaptive Shifts in the Regulation System of Seed Yield in Japanese Species of Epimedium (Berberidaceae)

Abstract Total seed yield per plant in one season was differentiated neither between Epimedium diphyllum and the E. grandiflorum complex ( E. grandiflorum and E. sempervirens ), nor between these two groups and one of their hybrid derived species, E. trifoliatobinatum . Total ovules per plant and seed-set rate per capsule ( SR ) did not vary greatly between these species, and seed weight ( SW ) was almost the same between them. The number of flowers per inflorescence ( F ) was also constant. However, the remaining reproductive component characters, ovule number per ovary ( O ) and inflorescence number per plant ( I ), were differentiated between the three taxa. These two characters were negatively correlated and a trade-off relationship occurred under the constant total seed yield (= O × F × I × SR × SW ). Ovule number per ovary was highly correlated with spur length of the flower. During the course of the hybrid speciation of E. trifoliatobinatum , selection pressure by pollinators on intermediate spur length seems to have favored plants with an intermediate ovule number. On the other hand, this selection pressure counteracted the increase of the inflorescence number under the trade-off. The resultant seed yield of E. trifoliatobinatum did not differ from that of the parental species, but the pattern of ovule allocation to ovaries (capsules) was altered.     

Morpho-functional principle of neuroendocrine system analysis

A new approach to the analysis of the neuroendocrine system (NES) is suggested. It is based on the fact of structural and metabolic determination of any effect on cell and cell aggregates. The principle of a common communication channel in the NES is formulated and a possible method of its formalization is proposed.     

Serosa membrane plays a key role in transferring vitellin polypeptides to the perivitelline fluid in insect embryos

In mid-embryogenesis, the stick insect Carausius morosus comes to be comprised of three distinct districts: the embryo proper, the yolk sac and the perivitelline fluid. A monolayered epithelium, the so-called serosa membrane, encloses the yolk sac and its content of vitellophages and large yolk granules. During embryonic development, the yolk sac declines gradually in protein concentration due to Vt polypeptides undergoing limited proteolysis to yield a number of Vt cleavage products of lower molecular weights. mAbs 1D1 and 5H11 are monoclonal antibodies raised against some of the Vt cleavage products generated by this process in the yolk sac. At the confocal microscope, antibody fluorescence is initially associated with a few yolk granules, while it is gradually displaced in the cytosolic spaces of the vitellophages. With the proceeding of embryonic development, label appears also in the serosa membrane in the form of clustered dots. At the ultrastructural level, gold particles are initially associated with the vitellophages that are labeled on a few yolk granules and in the cytosolic space flanking the yolk granules. Subsequently, the serosa cells become labeled on vesicles close to the yolk granules or just underneath the plasma membrane. Inside the serosa cells, label is also associated with granules budding from the Golgi apparatus, but never with the intercellular channels percolating the serosa membrane. These observations are interpreted as indicating that Vt cleavage products leak out from the yolk granules into the cytosolic spaces of the vitellophages and are eventually transferred to the perivitelline fluid via transcytosis through the serosa cells.