Microsatellite markers for evolutionary studies in the sexually deceptive orchid genus Chiloglottis

The orchids in the genus Chiloglottis are pollinated exclusively by sexual deception. We describe 20 variable microsatellite loci that will facilitate the study of the evolution and ecology of this specialized pollination system. Two loci were isolated from Chiloglottis trilabra, with the rest derived from Chiloglottis valida. All loci were polymorphic in C. valida (H_E 0.07–0.87). Most loci amplified, and were variable within close relatives of C. valida, and a number amplified more broadly, including outside the genus.     

Geographic variation of the Greater white-toothed shrew (Crocidura russula Hermann, 1780 Mammalia, Soricidae)

A multivariate morphometric study of the Greater white-toothed shrew ( C. russula ) throughout its Palearctic range was carried out to search for patterns of geographic variation within the species boundary. Burnaby's and multiple group principal component analysis allowed the adjustment of raw data with respect to within-sample allometric variation. Multivariate 'size-free'results show a stepped cline with the phenotypical trait reduction and shape change from the eastern to the western Maghreb. Pleistocene fossil mandibles proved to have low phenetic distances with eastern populations (Tunisia, east Algeria) and it is argued that their character set is the primitive condition. The ancestral Mid-Pleistocene shrews lived in a relatively more humid climate. Geo-climatic changes in the north African range during the Quaternary provoked phenetic variation of C. russula and, it can be argued, evolution of the modern western C.r. yebalensis. A historical process can thus be assumed as the main cause of this categorical variation, by segmentation of the species range due to geo-climatic events. Morphometric discontinuity within the C. russula Maghreb range is shown to be congruent with karyological and biochemical studies. Moroccan and Tunisian shrews differ, for example, in NFa chromosomes and electrophoretical traits. A stasipatric process should be invoked to explain categorical variation in the Maghreb range. Colonization and divergence of insular populations results in more or less differentiated geographic races. The populations of Ibiza and Pantelleria are close to the species threshold (Nei's D ≥ 0.1). The process of speciation undergone by the Greater white-toothed shrew results in a complex pattern of geographic variation, including both allopatric and non-allopatric modes.     

Isolation and characterization of polymorphic microsatellite loci from Wilsonia backhousei (Convolvulaceae)

Wilsonia backhousei is a clonal saltmarsh plant restricted to the southern latitudes of Australasia and threatened in New South Wales. We have identified eight informative microsatellite loci in the species from (AG)_n‐ and (AC)_n‐enriched libraries. In 48 samples from two populations we detected an average of five alleles per locus (range 2–8, average H_E = 0.45), of which 72% were unique to one population or the other. Six of the eight loci were also amplifiable in Wilsonia rotundifolia under the same reaction conditions. The markers will be excellent tools for use in the management and conservation of both species.     

Early Permian (Asselian) brachiopods from Karakorum (Pakistan) and their palaeobiogeographical significance

Abstract: Early Permian (Asselian) brachiopods collected from the Gircha Formation of western Karakorum (Pakistan) are described. They include Bandoproductus girchensis sp. nov., Kiangsiella sp. indet., Trigonotreta lyonsensis Archbold and Thomas, Trigonotreta larghii sp. nov., Spirelytha petaliformis (Pavlova), Punctospirifer afghanus Termier, Termier, de Lapparent and Marin, and ?Dielasma sp. indet. and belong to the Trigonotreta lyonsensis–Punctospirifer afghanus Assemblage Biozone, the oldest so far recovered from the Permian succession of Karakorum. The faunal succession of Karakorum records a significant biotic change from the Asselian to the Sakmarian, a shift in diversity and composition that is also recorded along most of the Gondwanan margin and Peri‐Gondwanan regions and that should be related to a major climatic change: the end of the Gondwanan glaciation. A palaeobiogeographical analysis has been performed by means of multivariate methods applying cluster and ordination analyses based on the Jaccard Coefficient and Simpson Index to a matrix consisting of the presence/absence of 23 brachiopod genera from seven geographical operational units from central Afghanistan to eastern Australia. The results suggest the occurrence of a single biotic province during the Asselian, the Indoralian Province, embracing all the faunal stations examined, as a consequence of the global cold phase related to the last pulse of the Gondwanan glaciation.     

Italian Peninsula preserves an evolutionary lineage of the fat dormouse Glis glis L. (Rodentia: Gliridae)

The present study examines the population genetic structure of fifty‐nine specimens of Glis glis (Linneaus, 1766) from thirteen localities in central Europe, sequencing a 400‐bp segment of the mitochondrial cytochrome b (cyt b) gene and a 673‐bp segment of the cytochrome c oxidase subunit I (COI) gene. The consensus tree obtained from Bayesian analysis revealed a robust dichotomy, showing two sister groups: one clade includes samples from a wide geographical area, extending from north‐central Europe to northern Italy (major branch sensu Bilton), and the other comprises samples collected in central and southern Italy and in Sicily (Italian branch). According to the Tajima–Nei model, the two phylogroups were separated by a sequence divergence of 0.8% (cyt b) – 2.6% (COI), showing the COI gene to be more informative than cyt b. On a smaller geographical scale, the Italian clade was further substructured, displaying geographical differentiation along the Peninsula. The gene pool in this area was patchy; whereas populations from Sicily Island demonstrated fixed cyt b and COI haplotypes, assuming processes of isolation and selection. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 11–21.     

Vector relationships and other characteristics of barley yellow striate mosaic virus (BYSMV)

Barley yellow striate mosaic virus (BYSMV) was inoculated by its planthopper vector Laodelphax striatellus (Homoptera, Delphacidae) to 44 species of Gramineae, 26 of which in eight tribes were infected. The virus was not transmitted through wheat seed nor did it infect five dicotyledonous hosts of other rhabdoviruses. The most susceptible species were in the tribes Festuceae and Hordeae. Barley, Bromus spp., oats, Phalaris canariensis, Setaria italica, Sorghum spp., and sweet corn cv. Golden were diagnostic hosts. Electron microscopy of crude sap was also a sensitive diagnostic method. Properties of BYSMV were determined by injecting L. striatellus with crude sap from infected barley. Sap was infectious after 10 min at 50–55 °C but not after 10 min at 60 °C, when diluted with buffer to 10^--² but not to 10^--³, when stored for 2 but not 4 days at 5 °C or when kept for 1 but not 2 days at 22 °C. The planthopper Javesella pellucida was an experimental vector of BYSMV but the virus was not transmitted by the leafhoppers Macrosteles sexnotatus or Psammotettix striatus (Homoptera, Cicadellidae). The latent period of BYSMV in L. striatellus was most commonly 15 or 16 days (minimum, 9 days; maximum, 29 days). The minimum acquisition access period for transmission was between 1 h and 5 h, and the minimum inoculation feeding time was 15 min. After 24 h and 8 day acquisition feeds, 30.4% and 42.8% respectively of L. striatellus transmitted BYSMV. When transferred daily, infective hoppers transmitted virus intermittently. The maximum retention of infectivity by L. striatellus was 36 days. Two of five infective females transmitted BYSMV transovarially. Larvae became infective in the second wk after hatching and transmitted for up to 3 wk.     

Increase in calmodulin level in the early phases of radish seed (Raphanus sativus) germination

Abstract Calmodulin (Cam), the heat-stable, ubiquitous, Ca²⁺-dependent regulator protein, has been purified to apparent homogeneity from germinating radish seeds (Raphanus sativus). The characteristics of radish Cam-molecular weight, absorption spectrum, Ca²⁺-dependent activation of brain phosphodiesterase (PDE)-are very similar to those described for Cam from other plant materials. Radish Cam, like other plant Cam, shows some differences to Cam of calf brain. The total amount of Cam in radish embryos at 24 h of germination is ca. 37 μg g⁻¹ fresh weight. Approximately 95% of the total amount of Cam is present in the soluble fraction (supernatant at 100,000 g). The level in the embryo axis strongly increases in the first 24 h of germination (+540%); this increase is strongly reduced when the germination is inhibited by abscisic acid (ABA). In the presence of Ca²⁺, no ‘free’ Cam (i.e. not bound to other structures) is present in the soluble fraction, suggesting that, during early germination, Cam level is a limiting factor for the activities of Ca²⁺ -Cam-dependent systems. These studies suggest that Cam plays an important role in the early phases of seed germination. An inhibitor of the Ca²⁺-Cam-dependent phosphodiesterase is present in the soluble fraction from radish embryos; this substance decreases during germination. A possible role of this inhibitor during the early germination phases is hypothesized.     

Capacitive effect of cavitation in xylem conduits: results from a dynamic model

Embolisms decrease plant hydraulic conductance and therefore reduce the ability of the xylem to transport water to leaves provided that embolized conduits are not refilled. However, as a xylem conduit is filled with gas during cavitation, water is freed to the transpiration stream and this transiently increases xylem water potential. This capacitive effect of embolism formation on plant function has not been explicitly quantified in the past. A dynamic model is presented that models xylem water potential, xylem sap flow and cavitation, taking into account both the decreasing hydraulic conductance and the water release effect of xylem embolism. The significance of the capacitive effect increases in relation to the decreasing hydraulic conductance effect when transpiration rate is low in relation to the total amount of water in xylem conduits. This ratio is typically large in large trees and during drought.