Vegetation and fire history with their implication for climatic change and fire events since the last deglacial in the Aso Valley, central Kyushu, southwestern Japan: new pollen and charcoal data

To better understand the response of forest vegetation to climate and fire regimes with reference to human activities over the last deglacial period in the Aso Caldera, central Kyushu, southwestern Japan, a 33.9 m long sediment core was examined in order to reconstruct the vegetational and fire history using pollen and charcoal analyses. The results show that a cool temperate broad-leaved deciduous forest, dominated by Quercus (deciduous oaks) with Carpinus and Fagus, prevailed in the Aso Valley from ca. 14.6 ka cal. b.p., indicating warming since the last glacial period. The landscape was presumably covered by a mosaic of deciduous Quercus forests and terrestrial Artemisia communities. Around 12.8–11.7 ka cal. b.p., Quercus dominated the forest and fires occurred frequently. Co-expansion of distinctive Ulmus–Zelkova and Celtis–Aphananthe forests coupled with a progressive retreat of Quercus in the early Holocene could reflect a strengthening of the East Asian summer monsoon under mild and humid climate conditions. Around 8 ka cal. b.p., significant increases in Cyclobalanopsis (evergreen oaks), Castanopsis/Castanea and Podocarpus indicate a further warming, in particular an increased winter temperature. Warm temperate lucidophyllous forests, dominated by Cyclobalanopsis, flourished after 7.3 ka cal. b.p., probably corresponding to the “Holocene Climatic Optimum” interval. Progressive expansion of Quercus at the expense of Cyclobalanopsis began around 6.4 ka cal. b.p. and paralleled an increase in charcoal until ca. 4.8 ka cal. b.p.; this could be evidence of fire disturbance induced by the early-middle Jomon people. The disturbed evergreen forest experienced a temporary recovery but then opened again from 3.6 ka cal. b.p. due to extensive fire deforestation, as suggested by the high charcoal levels during this time. Human exploitation and buckwheat (Fagopyrum) agriculture may have contributed to the opening of the forest, which allowed secondary forests (primarily Pinus and Quercus) and herbaceous communities (mainly Poaceae) to spread. These results are discussed in comparison with other high-resolution pollen data from western Japan to better elucidate the vegetation and fire history over the last deglacial in the Aso Caldera.     

Seasonal variations in larval biomass and biochemical composition of brown shrimp, Crangon crangon (Decapoda, Caridea), at hatching

The “brown shrimp”, Crangon crangon (Linnaeus 1758), is a benthic key species in the North Sea ecosystem, supporting an intense commercial fishery. Its reproductive pattern is characterized by a continuous spawning season from mid-winter to early autumn. During this extended period, C. crangon shows significant seasonal variations in egg size and embryonic biomass, which may influence larval quality at hatching. In the present study, we quantified seasonal changes in dry weight (W) and chemical composition (CHN, protein and lipid) of newly hatched larvae of C. crangon. Our data revealed significant variations, with maximum biomass values at the beginning of the hatching season (February–March), a decrease throughout spring (April–May) and a minimum in summer (June–September). While all absolute values of biomass and biochemical constituents per larva showed highly significant differences between months (P < 0.001), CHN, protein and lipid concentrations (expressed as percentage values of dry weight) showed only marginally significant differences (P < 0.05). According to generalized additive models (GAM), key variables of embryonic development exerted significant effects on larval condition at hatching: The larval carbon content (C) was positively correlated with embryonic carbon content shortly after egg-laying (r ² = 0.60; P < 0.001) and negatively with the average incubation temperature during the period of embryonic development (r ² = 0.35; P < 0.001). Additionally, water temperature (r ² = 0.57; P < 0.001) and food availability (phytoplankton C; r ² = 0.39; P < 0.001) at the time of hatching were negatively correlated with larval C content at hatching. In conclusion, “winter larvae” hatching from larger “winter eggs” showed higher initial values of biomass compared to “summer larvae” originating from smaller “summer eggs”. This indicates carry-over effects persisting from the embryonic to the larval phase. Since “winter larvae” are more likely exposed to poor nutritional conditions, intraspecific variability in larval biomass at hatching is interpreted as part of an adaptive reproductive strategy compensating for strong seasonality in plankton production and transitory periods of larval food limitation.     

In vivo effects of zoledronic acid on peripheral γδ T lymphocytes in early breast cancer patients

Introduction

Amino-bisphosphonates are potent activators of human γδ T cells. The aim of our study was to evaluate the immunomodulating properties of a single-dose of zoledronic acid (ZA) on γδ T cells in a select group of disease-free breast cancer patients with osteopenia.

Materials and methods

Blood samples were obtained, from 23 patients, before and 7, 28, 56, 90 and 180 days after a single-dose (4 mg) of ZA and analyzed by flow cyometry.

Results

A significant decrease of the different γδ T cell subsets was observed: Naïve (CD3+/Vdelta2+/CD45RA+/CD27+) after 180 days (P < 0.01); Central Memory (CD3+/Vdelta2+/CD45RA-CD27+) after 28 (P < 0.05), 90 (P < 0.01) and 180 days (P < 0.01); and Effector Memory (CD3+/Vdelta2+/CD45RA-/CD27-) after 56 (P < 0.01) and 90 (P < 0.05) days. Based on the observed γδ T cells kinetics patients could be divided in two groups: “responders” that showed a significant decrease in total numbers of γδ T cells and “non-responders” that showed no significant change. However, in vitro phosphoantigen stimulation of patients cells did not show significant differences in terms of IFN-γ response by Vδ2 T cells.

Conclusion

We describe for the first time a long-lasting activation of effector subsets of γδ T cells in disease-free breast cancer patients after a single-dose of ZA. Our results highlight the need to further investigate the clinical significance of the immunomodulating properties of N-BPs.     

2-methylbutanal, a volatile biomarker, for non-invasive surveillance of Proteus

Pathogen detection needs a paradigm shift from time-consuming conventional microbiological and biochemical tests to much simpler identification methods with higher sensitivity and specificity. In this regard, a simple detection method for frequently isolated nosocomial uropathogen, Proteus spp., was developed using the characteristic volatile 2-methylbutanal released in Luria Bertani broth. The instant reaction of the compound with 5-dimethylaminonaphthalene-1-sulfonylhydrazine (DNSH) has been adapted to develop a sensitive fluorescence assay named “ProteAl” (Prote, “Proteus” & Al, “Aldehyde”). The assay was performed by direct addition of the fluorescence reagent to the culture after 7 h of growth. The distinct green fluorescence by Proteus (other organisms show orange fluorescence) served as the simplest and quicker identification test available for Proteus. In the laboratory, it exhibited 100 % specificity and 100 % sensitivity during testing of 95 strains including standard and known clinical isolates representing frequently encountered uropathogens.     

Achene structure and taxonomy of North American Bolboschoenus (Cyperaceae)

Surface and transverse section achene structures ofBolboschoenus maritimus, B. robustus, B. fluviatilis, B. novae-angliae, B. glaucus, and the putative hybridsB. maritimus × B. rubustus andB. glaucus × B. maritimus from North America are described and illustrated with SEM micrographs. The same three type of pericarp structure reported by Browning and Gordon-Gray (1993) from southern Africa were found except that the “type 2” (B. glaucus) was not matched precisely. Intermediate achene structures and other evidence support both the hybrid origin ofB. novae-angliae (=B. fluviatilis × B. robustus) and hybridization betweenB. glaucus andB. maritimus. The new combinationBolboschoenus novae-angliae is made.     

Age structure, growth and mortality estimates of an endemic Ptychobarbus dipogon (Regan, 1905) (Cyprinidae: Schizothoracinae) in the Lhasa River, Tibet

Ptychobarbus dipogon is an endemic fish in the Yarlung Tsangpo River, but its biology is poorly known. We sampled 582 specimens (total length, TL, between 70.6 and 593.0 mm) from April 2004 to August 2006 in the Lhasa River, Tibet. We estimated ages based on the counts of alternating opaque and translucent zones (annuli) in thin transverse sections of lapilli otoliths. Ages ranged from 1⁺ to 23⁺ years for males and 1⁺ to 44⁺ for females. The observed 44⁺ years was the oldest reported for schizothoracine fishes. Females attained a larger size than males. The TL–weight relationship was W?=?7.12?×?10^?6 TL ^3.006 for combined sexes. The growth parameters fitted von Bertalanffy growth functions were $L_\infty = 598.66\,{\text{mm}}$ , k?=?0.0898 year^?1, t ₀?=??0.7261 year and $W_\infty = 1585.38\;{\text{g}}$ for females and $L_\infty = 494.23{\text{ mm}}$ , k?=?0.1197 year^?1, t ₀?=??0.7296 year and $W_\infty = 904.88{\text{ g}}$ for males. The longevities of 32.7 year for females and 24.3 year for males were similar to the observed ages. Using an empirical model we estimated the instantaneous rate of total mortality (Z) at 0.28 per year in the lower reaches. Z in the upper and middle stocks was close to the M because of unexploited or lightly exploited stock. Protracted longevity, slow growth, low natural mortality and large body size were typical characteristics of P. dipogon. The current declining trend of P. dipogon could be prevented by altering fishing regulations.     

Effects of negative air ions on oxygen uptake kinetics,recovery and performance in exercise: a randomized,double-blinded study

Limited research has suggested that acute exposure to negatively charged ions may enhance cardio-respiratory function, aerobic metabolism and recovery following exercise. To test the physiological effects of negatively charged air ions, 14 trained males (age: 32?±?7 years; \( \overset{\cdotp }{V}{\mathrm{O}}_{2 \max } \) : 57?±?7 mL min^?1 kg^?1) were exposed for 20 min to either a high-concentration of air ions (ION: 220?±?30?×?10³ ions cm^?3) or normal room conditions (PLA: 0.1?±?0.06?×?10³ ions cm^?3) in an ionization chamber in a double-blinded, randomized order, prior to performing: (1) a bout of severe-intensity cycling exercise for determining the time constant of the phase II \( \overset{\cdotp }{V}{\mathrm{O}}_2 \) response (τ) and the magnitude of the \( \overset{\cdotp }{V}{\mathrm{O}}_2 \) slow component (SC); and (2) a 30-s Wingate test that was preceded by three 30-s Wingate tests to measure plasma [adrenaline] (ADR), [nor-adrenaline] (N-ADR) and blood [lactate] (B_Lac) over 20 min during recovery in the ionization chamber. There was no difference between ION and PLA for the phase II \( \overset{\cdotp }{V}{\mathrm{O}}_2 \) τ (32?±?14 s vs. 32?±?14 s; P?=?0.7) or \( \overset{\cdotp }{V}{\mathrm{O}}_2 \) SC (404?±?214 mL vs 482?±?217 mL; P?=?0.17). No differences between ION and PLA were observed at any time-point for ADR, N-ADR and B_Lac as well as on peak and mean power output during the Wingate tests (all P?>?0.05). A high-concentration of negatively charged air ions had no effect on aerobic metabolism during severe-intensity exercise or on performance or the recovery of the adrenergic and metabolic responses after repeated-sprint exercise in trained athletes.     

Comparative QTL analysis of root lesion nematode resistance in barley

Key message

This study demonstrates for the first time that resistance to different root lesion nematodes ( P. neglectus and P. penetrans ) is controlled by a common QTL. A major resistance QTL ( Rlnnp6H ) has been mapped to chromosome 6H using two independent barley populations.

Abstract

Root lesion nematodes (Pratylenchus spp.) are important pests in cereal production worldwide. We selected two doubled haploid populations of barley (Igri × Franka and Uschi × HHOR 3073) and infected them with Pratylenchus penetrans and Pratylenchus neglectus. Nematode multiplication rates were measured 7 or 10 weeks after infection. In both populations, continuous phenotypic variations for nematode multiplication rates were detected indicating a quantitative inheritance of resistance. In the Igri × Franka population, four P. penetrans resistance QTLs were mapped with 857 molecular markers on four linkage groups (2H, 5H, 6H and 7H). In the Uschi × HHOR 3073 population, eleven resistance QTLs (P. penetrans and P. neglectus) were mapped with 646 molecular markers on linkage groups 1H, 3H, 4H, 5H, 6H and 7H. A major resistance QTL named Rlnnp6H (LOD score 6.42–11.19) with a large phenotypic effect (27.5–36.6 %) for both pests was mapped in both populations to chromosome 6H. Another resistance QTL for both pests was mapped on linkage group 5H (Igri × Franka population). These data provide first evidence for common resistance mechanisms against different root lesion nematode species. The molecular markers are a powerful tool for the selection of resistant barley lines among segregating populations because resistance tests are time consuming and laborious.     

Development of somatic hybrids Solanum × michoacanum Bitter. (Rydb.) (+) S. tuberosum L. and autofused 4x S. × michoacanum plants as potential sources of late blight resistance for potato breeding

Key message

Phytophthora infestans resistant somatic hybrids of S. × michoacanum (+) S. tuberosum and autofused 4 x S. × michoacanum were obtained. Our material is promising to introgress resistance from S. × michoacanum into cultivated potato background.

Abstract

Solanum × michoacanum (Bitter.) Rydb. (mch) is a wild diploid (2n = 2x = 24) potato species derived from spontaneous cross of S. bulbocastanum and S. pinnatisectum. This hybrid is a 1 EBN (endosperm balance number) species and can cross effectively only with other 1 EBN species. Plants of mch are resistant to Phytophthora infestans (Mont) de Bary. To introgress late blight resistance genes from mch into S. tuberosum (tbr), genepool somatic hybridization between mch and susceptible diploid potato clones (2n = 2x = 24) or potato cultivar Rywal (2n = 4x = 48) was performed. In total 18,775 calli were obtained from postfusion products from which 1,482 formed shoots. The Simple Sequence Repeat (SSR), Cleaved Amplified Polymorphic Sequences (CAPS) and Random Amplified Polymorphic DNA (RAPD) analyses confirmed hybrid nature of 228 plants and 116 autofused 4x mch. After evaluation of morphological features, flowering, pollen stainability, tuberization and ploidy level, 118 somatic hybrids and 116 autofused 4x mch were tested for late blight resistance using the detached leaf assay. After two seasons of testing three somatic hybrids and 109 4x mch were resistant. Resistant forms have adequate pollen stainability for use in crossing programme and are a promising material useful for introgression resistance from mch into the cultivated potato background.     

Expression patterns of WRKY genes in di-haploid Populus simonii × P. nigra in response to salinity stress revealed by quantitative real-time PCR and RNA sequencing

Key message

Spatio-temporal expression patterns of 13 out of 119 poplar WRKY genes indicated dynamic and tissue-specific roles of WRKY family proteins in salinity stress tolerance.

Abstract

To understand the expression patterns of poplar WRKY genes under salinity stress, 51 of the 119 WRKY genes were selected from di-haploid Populus simonii × P. nigra by quantitative real-time PCR (qRT-PCR). We used qRT-PCR to profile the expression of the top 13 genes under salinity stress across seven time points, and employed RNA-Seq platforms to cross-validate it. Results demonstrated that all the 13 WRKY genes were expressed in root, stem, and leaf tissues, but their expression levels and overall patterns varied notably in these tissues. Regarding overall gene expression in roots, the 13 genes were significantly highly expressed at all six time points after the treatment, reaching the plateau of expression at hour 9. In leaves, the 13 genes were similarly up-regulated from 3 to 12 h in response to NaCl treatment. In stems, however, expression levels of the 13 genes did not show significant changes after the NaCl treatment. Regarding individual gene expression across the time points and the three tissues, the 13 genes can be classified into three clusters: the lowly expressed Cluster 1 containing PthWRKY28, 45 and 105; intermediately expressed Clusters 2 including PthWRKY56, 88 and 116; and highly expressed Cluster 3 consisting of PthWRKY41, 44, 51, 61, 62, 75 and 106. In general, genes in Cluster 2 and 3 displayed a dynamic pattern of “induced amplification—recovering”, suggesting that these WRKY genes and corresponding pathways may play a critical role in mediating salt response and tolerance in a dynamic and tissue-specific manner.     

Haploid plants carrying a sodium azide-induced mutation (fdr1) produce fertile pollen grains due to first division restitution (FDR) in maize (Zea mays L.)

Key message

We induced a fdr1 mutation in maize which makes haploid plants male fertile due to first division restitution; the optimum sodium azide treatment on maize kernels has been identified.

Abstract

Sodium azide mutagenesis experiments were performed on haploid and diploid maize plants. Kernels with haploid embryos of maize inbred line B55 were induced by pollinating with RWS pollen. These kernels were treated with 0.2, 0.5, or 1.0 mM sodium azide solution for 2 h. The 0.5 mM solution was optimal for inducing numerous albino sectors on the treated plants without significant damage. Kernels of a maize hybrid, Oh43 × B55, were treated with sodium azide solutions at concentrations of 1.5, 2.0, 2.5, and 3.0 mM. Haploids were generated by pollinating RWS pollen. The highest rate of chlorophyll mutations in seedlings (15.3 % [13/85]) was recorded with the 2.5 mM concentration. A mutated haploid plant (PP1-50) with higher pollen fertility was isolated during the experiments. This haploid plant produced four kernels on the ear after selfing. These kernels were germinated and produced ears with full seed set after selfing. The haploid plants induced from PP1-50 diploids also exhibited high pollen fertility. In situ hybridization studies showed that meiocytes in PP1-50 haploid anthers underwent first division restitution at a rate of 48 % and produced equally divided dyads. We designated the genetic factor responsible for this high pollen fertility as fdr1. PP1-50 haploid ears exhibited high levels of sterility, as seen for regular haploids. Diploid PP1-50 meiocytes in the anther underwent normal meiosis, and all selfed progenies were normal diploids. We concluded that the fdr1 phenotype is only expressed in the anthers of haploid plants and not in the anthers of diploid plants.     

Plasma matrix metalloproteinase-9 levels, <Emphasis Type="Italic">MMP</Emphasis>-<Emphasis Type="Italic">9</Emphasis> gene haplotypes,and cardiovascular risk in obese subjects

Plasma matrix metalloproteinase (MMP)-9 is a predictor of cardiovascular mortality, and MMP-9 polymorphisms affect plasma MMP-9 levels. However, no study examined whether MMP-9 haplotypes affect MMP-9 levels in obese adults. We examined whether MMP-9 polymorphisms and haplotypes are associated with obesity, and whether they affect MMP-9 levels in obese subjects. We examined the plasma levels of MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1 in 105 subjects with normal weight (controls), 100 obese subjects, and 156 obese subjects with ≥3 metabolic risk factors (MRFs). We determined genotypes for three polymorphisms: C-1562T (rs3918242), Q279R (A>G, rs17576), and R668Q (G>A, rs17577). MMP-9 levels and activity (MMP-9/TIMP-1 ratio) were higher in obese subjects than in controls (P < 0.05). However, MMP-9 levels were higher in obese subjects with ≥3 MRFs than in obese subjects (P < 0.05). Obese subjects with ≥3 MRFs carrying the GA+AA genotypes for R668Q (G>A) polymorphism had higher MMP-9 levels than subjects carrying the AA genotype (P < 0.05). The “T, G, A” haplotype was more common in both groups of obese subjects than in controls (OR 3.95 and 4.39, respectively; P < 0.01). Notably, obese subjects with ≥3 MRFs carrying the “T, G, A” haplotype had higher MMP-9 levels than subjects carrying the “C, A, G” reference haplotype (P < 0.05). The “T, G, A” haplotype was associated with an increased risk of obesity and affected MMP-9 levels in obese subjects with ≥3 MRFs. Our findings suggest that plasma MMP-9 levels and MMP-9 haplotypes may help to discriminate obese subjects at an increased cardiovascular risk.     

On the status of “Urotherium antiquum” (Ameghino) (Xenarthra,Glyptodontidae)

Within the Late Neogene Glyptodontidae of the Pampean region of Argentina, “Urotherium antiquum” was described on the basis of some associated osteoderms of the dorsal carapace, which in addition include a partial skull and left hemimandible. The diagnostic characters are located on the exposed surface of the osteoderms of the dorsal carapace which somewhat resembles those of the Pleistocene genus Neuryurus. Although the relationship of “U. antiquum” to the remaining Glyptodontidae has never been clarified, some cladistic analyses suggest a close phylogenetic affinity with the clade composed of Plohophorus + (Glyptodon + Doedicurus). A careful comparison of “U. antiquum” to well-characterized taxa with similar stratigraphic and geographic provenance reveals that no significant skull differences are observed from Plohophorus figuratus Ameghino. It seems likely that the alleged ornamentation pattern that characterizes this species was produced by a taphonomic alteration of the exposed surface of the osteoderms, a process broadly distributed in glyptodonts having a “rosette” ornamentation pattern. Finally, some characters present in the osteoderms of the type specimen of “U. antiquum” suggest that it may be a juvenile specimen. In summary, “U. antiquum” should be considered a junior synonym of P. figuratus.     

Physiological responses of Haloxylon ammodendron to rainfall pulses in temperate desert regions,Northwestern China

Key message

Physiological characteristics except WUE of H. ammodendron have obvious response to rainfall pulses of 6–12 mm, and rainfall in this range at least is “effective” precipitation for H. ammodendron.

Abstract

In water-limited ecosystems, pulses of rainfall can trigger a cascade of plant physiological responses. Small precipitation events account for a large proportion of the precipitation received in arid regions. Their potential ecological importance, however, has previously been ignored. Here the responses of the physiological characteristics of Haloxylon ammodendron (H. ammodendron) to rainfall were evaluated by rainfall manipulative experiments during the growing season of 2012 in the desert region of Northwestern China. Net Photosynthesis rate (P _n), transpiration (Tr), water use efficiency (WUE), stomatal conductance (G _s), internal concentration of CO₂ (C _i), sap flow, leaf water potential (Ψ), and soil volumetric water content (SVWC) were monitored throughout the experimental period. The results showed that the water status of H. ammodendron is highly sensitive to rainfall pulses. P _n, Tr, and G _s increased with rainfall and then decreased gradually after rainfall. WUE decreases after rainfall and increases in times of increasing drought, although within a narrow range. H. ammodendron has a special buffering ability induced by harsh environmental conditions, particularly the rainfall patterns. Collectively, a 6-mm or greater rainfall amount is “effective” precipitation for H. ammodendron from the perspective of plant physiology. This study result is essential to the theories and practice of combating desertification.     

Evidence for genetic erosion of a California native tree, <Emphasis Type="Italic">Platanus racemosa</Emphasis>, via recent,ongoing introgressive hybridization with an introduced ornamental species

When non-native, genetically diverse species are introduced, hybridization with native congeners may erode the genetic composition of local species, perhaps even resulting in extinction. While such events may lead to adverse consequences at the community and ecosystem level, few studies exist on ecologically important tree species. In the genus Platanus, introgressive hybridization is widespread, and one common ornamental species, introduced to California during the late 19th century, is itself a hybrid. Our microsatellite analysis of more than 400 Platanus trees from north-central California reveals a complex pattern of invasion and hybridization in an age-structured population. By using size as a proxy for age, we have demonstrated that the Platanus population of north-central California has recently gained genetic diversity and effective population size. Principal coordinate analysis (PCoA) and genetic admixture analysis (STRUCTURE) both reveal a strong differentiation of genotypes into two main genetic clusters, with a large number of admixed genotypes. One of the genetic clusters identified is heavily biased towards younger trees, including samples from locations with relatively recently planted ornamental trees likely to be P. × hispanica (formerly known as P. × acerifolia). We conclude that the two genetic clusters correspond to the native P. racemosa and the introduced invasive hybrid species P. × hispanica. Additional hybridization between the invasive ornamental and the native species has occurred in California, and recent hybrid trees are more likely to be younger than trees without admixture. Our findings suggest that the observed increase in genetic diversity among California Platanus is due to rampant ongoing introgression, which may be threatening the continued genetic distinctiveness of the native species. This is cause for concern from a conservation standpoint, due to a direct loss of genetic distinctiveness, and a potential reduction in habitat value of associated species.     

Inter-specific territoriality in a Canis hybrid zone: spatial segregation between wolves, coyotes, and hybrids

Gray wolves (Canis lupus) and coyotes (Canis latrans) generally exhibit intraspecific territoriality manifesting in spatial segregation between adjacent packs. However, previous studies have found a high degree of interspecific spatial overlap between sympatric wolves and coyotes. Eastern wolves (Canis lycaon) are the most common wolf in and around Algonquin Provincial Park (APP), Ontario, Canada and hybridize with sympatric gray wolves and coyotes. We hypothesized that all Canis types (wolves, coyotes, and hybrids) exhibit a high degree of spatial segregation due to greater genetic, morphologic, and ecological similarities between wolves and coyotes in this hybrid system compared with western North American ecosystems. We used global positioning system telemetry and probabilistic measures of spatial overlap to investigate spatial segregation between adjacent Canis packs. Our hypothesis was supported as: (1) the probability of locating wolves, coyotes, and hybrids within home ranges ( $\bar{x}$  = 0.05) or core areas ( $\bar{x}$  < 0.01) of adjacent packs was low; and (2) the amount of shared space use was negligible. Spatial segregation did not vary substantially in relation to genotypes of adjacent packs or local environmental conditions (i.e., harvest regulations or road densities). We provide the first telemetry-based demonstration of spatial segregation between wolves and coyotes, highlighting the novel relationships between Canis types in the Ontario hybrid zone relative to areas where wolves and coyotes are reproductively isolated. Territoriality among Canis may increase the likelihood of eastern wolves joining coyote and hybrid packs, facilitate hybridization, and could play a role in limiting expansion of the genetically distinct APP eastern wolf population.     

High-frequency generation and characterization of intergeneric hybrids and haploids from new wheat–barley crosses

Key message

Hybrid plants and a high frequency of maternal haploids were obtained using an efficient wheat–barley hybridization system (with new genotype combinations) and confirmed by several cytological and molecular tools.

Abstract

An efficient hybridization system between wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) is presented on the basis of three new genotype combinations. A particularly high, 14 % frequency of plant regeneration per florets was achieved in the wheat–barley genotype combination of ‘Sichuan’ × ‘Morex’. The genome composition in 42 of the 95 plants regenerated by embryo rescue was determined using ploidy analysis, genomic in situ hybridization and the application of chromosome arm-specific molecular markers (SSR and STS). A high overall frequency (76 %) of maternal (wheat) haploids was observed in all the tests for all three cross combinations. A major implication of this observation is that this new hybridization system represents a useful tool to study the mechanism of uniparental chromosome elimination in cereals.     

Carbon assimilation variation and control in Picea rubens,Picea mariana,and their hybrids under ambient and elevated CO2

Key message

After 3 years of CO ₂ treatments, A stimulation from ambient to elevated CO ₂ was strongly related to the total dry mass change (%), supporting the sink demand A hypothesis.

Abstract

Adaptations related to gas exchange are important fitness traits in plants and have significant growth and ecological implications. Assimilation (A) and assimilation to internal CO₂ (AC _i ) response curve parameters were quantified from a red spruce (RS) (Picea rubens Sarg.)—black spruce (BS) [P. mariana (Mill.) B.S.P.] controlled-cross hybrid complex grown under ambient and elevated CO₂ conditions. Under ambient conditions, maximum A (A _max), maximum rate of carboxylation by rubisco (V _cmax), maximum rate of electron transport (J _max), and carboxylation efficiency (CE) generally increased with increasing BS content; however, under elevated CO₂ conditions, hybrid index 50 (hybrid index number is the percentage of RS, balance BS) often had greater values than the other indices. There were significant hybrid index, CO₂, and hybrid index × CO₂ effects for A _growth at 360 ppm (A ₃₆₀) and 720 ppm (A ₇₂₀). The net A stimulation (A _stim), from ambient to elevated CO₂ treatment after 3 years was 10.8, 57.8, 74.1, 69.8, and 58.7 %, for hybrid indices 0 (BS), 25, 50, 75, and 100 (RS), respectively. Why does BS have the least A _stim, hybrid index 50 the most, and RS a moderate level? There was a significant relationship between A ₃₆₀ and ambient total biomass among indices (P = 0.096), but none was found between A ₇₂₀ and elevated total biomass. However, A _stim (%) was strongly related to the change in total dry mass (%) in response to elevated CO₂ (R ² = 0.931, P = 0.008), supporting the hypothesis that sink demand drives A. Traits A _max, V _cmax and J _max were correlated to total chlorophyll concentration. Moreover, A _max V _cmax and J _max also showed a significant underlying male effect, particularly under ambient conditions consistent with the paternal inheritance of the chloroplast genome.     

The introduction of Citrus to Italy, with reference to the identification problems of seed remains

While some consensus exists about the roles of southwestern China and northeastern India in the origin and diversification of the genus Citrus, the scarcity of its archaeological remains, as well as some methodological limits in unequivocally identifying taxa, do not facilitate reconstruction of the tempo and mode of spread of the genus towards other areas, notably the Mediterranean. Recent discoveries of archaeobotanical macro-remains (seeds and fruits) and pollen records from some important Italian sites in the Vesuvius area and Rome can be used to shed new light on this history. However, due to their morphological variability and the changes derived from the preservation processes, Citrus seeds appear difficult to recognise. In this paper, we present criteria to facilitate their precise identification, based on the observation of the morphology of modern seeds, and most of all the seed-coat patterns. The reference material consisted of “archaic” varieties of C. medica L. (citron), C. × limon (L.) Burm. f. (lemon) and seeds of C. × aurantium L. (bitter or Seville orange), C. × aurantiifolia (Christm.) Swingle (lime) and C. reticulata Blanco (tangerine, mandarin orange). Considering the fact that the general morphology of seeds, especially when mineralised, can confuse the identification of Citrus with Maloideae types, we also add criteria for the recognition of Cydonia oblonga Mill. (quince), Malus domestica Borkh. (apple), Pyrus communis L. (pear), Sorbus aria (L.) Crantz (whitebeam) and S. domestica L. (service tree). The observation of the keels and cell patterns was mostly useful to identify new material from Pompeii and Rome dating from the 3rd/2nd century b.c. and the Augustan period around the beginning of the Common (Christian) Era as C. medica L. (citron) and C. cf. × limon (L.) Burm. f. (possible lemon). The classical Greek and Latin sources helped us to understand the use and status of citrus fruits in the ancient world and, in combination with all available archaeobotanical remains compiled in this paper, have allowed us to discuss the spread of Citrus from its regions of origin to the eastern Mediterranean and then within the Mediterranean.     

The novel ethylene antagonist, 3-cyclopropyl-1-enyl-propanoic acid sodium salt (CPAS), increases grain yield in wheat by delaying leaf senescence

Orchid is a major floral crop around the world and Dendrobium hybrids are considered to be one of the most popular orchids. In vitro germination of hybrid seeds is a common practice among orchid growers, however, in many cross pollinations the embryos may not develop to maturity, leading to poor seed germination. The effect of seed maturity and sucrose concentration were investigated via asymbiotic germination of nobile Dendrobium hybrids. Capsules were harvested from two hybrids (Den. Lucky Girl × Den. Second Love ‘Kirameki’ and Den. Lucky Girl × Den. Hamana Lake ‘Kumi’) and one selfing of Den. Second Love ‘Kirameki’ at 2, 3, 4, and 5 months after pollination and immature seeds were taken. Immature seeds from 3- to 5-month old capsules could be successfully germinated on Hyponex based medium. Immature seeds from 4-month old capsules showed greatest germination rate of tested treatments, whereas 3-month old immature seeds showed the least germination. After 6 weeks of in vitro culture, protocorms derived from embryos developed on every concentration of sucrose, but germination was greater at lower concentrations. Greater concentration of sucrose decreased normal-developed protocorms.