Two new genera and two new species of proteocephalidean tapeworms (Eucestoda) from reptiles and amphibians in Australia

The examination of the type series of Ophiotaenia Gallardi (Johnston, 1911) (syn. Proteocephalus gallardi Johnston, 1911) revealed that it is a mixture of two species of different genera. Lectotype of Ophiotaenia gallardi is designated and the species is redescribed on the basis of it, conspecific paralectotypes and additional materials. The remaining part of the type series belongs to Vandiermenia gen. n. (Acanthotaeniinae), with V Beveridgei sp. n. as the type- and only species. The new genus differs from all other acanthotaeniine genera, i.e. Rostellotaenia Freze, 1963, Acanthotaenia von Linstow, 1903 and Kapsulotaenia Freze, 1963, by the presence of cortical uterine stem and paramuscular vitelline follicles, particular structure of the internal longitudinal musculature (absent laterally and more developed than in the three above-mentioned genera) and testes limited in two fields separated medially. Type series of Ophiotaenia mjobergi (Nybelin, 1917) (syn. Crepidobothrium mjobergi Nybelin, 1917), O. amphiboluri (Nybelin, 1917) (syn. Crepidobothrium amphiboluri Nybelin, 1917), O. striata (Johnston, 1914) (syn. Acanthotaenia striata Johnston, 1914) and O. longmani Johnston, 1916 are revised and compared with Ophiotaenia gallardi. Australotaenia hylae (Johnston, 1912) comb. n. is proposed for Ophiotaenia hylae Johnston, 1912. Australotaenia gen. n. differs from the remaining genera of the subfamily Acanthotaeniinae by (1) the Type 2 of the formation of the uterus (sensu de Chambrier et al. 2004) (all the other acanthotaeniines have the Type 1 of uterine development), (2) the cortical position of the uterine stem (all the other genera have medullary uterine stem) and (3) the morphology of the internal longitudinal musculature, which is composed of few well-developed bundles of fibres (in contrast to the other genera). The new genus also differs from ?by eggs not in clusters, the presence of two testicular fields (versus one in Vandiermenia) and the structure of the longitudinal internal musculature with only 8-10 bundles (versus formed by numerous bundles and with the presence of secondary muscles in Vandiermenia). Ophiotaenia sp. sensu de Chambrier (2004), a parasite of Litoria moorei, is described as Australotaenia grobeli sp. n., which can be distinguished from Australotaenia hylae by the smaller number of testes (46-76 versus 74-106), greater cirrus-sac length/width of proglottis ratio (27-33% versus 17-19%) and the smaller ovary width/proglottis width ratio (55-63% versus 68-71%).     

Volume change of bread and bread crumb during cooling,chilling and freezing,and the impact of baking

During baking, bread dough undergoes an expansion followed by a slight contraction at the end of baking. The contraction during baking has been evidenced by some authors. However, there is a limited amount of literature about the contraction of the crumb during the chilling phase and also during the freezing phase in the case of freezing. A study has been carried out to better understand the impact of the baking degree on the contraction of the crumb during chilling after baking and during freezing. The volume of the samples has been evaluated with a laser volumeter. Breads (70 g dough) were baked until reaching 75 °C, 85 °C, 95 °C, 98 °C and then 98 °C for 10 min. Results showed that a longer baking resulted in a lower contraction of the bread. The volume change was between 25% and 2.5% for baking at 75 °C—0 min dwell and 98 °C—10 min dwell, respectively. The contraction was compared to the contraction of degassed bread crumb samples, which was more important. SEM pictures showed that the degree of baking also corresponded to a very different structure of the crumb. For the longer baking, the starch granules were fully gelatinized and no ghosts of starch granules were visible. The magnitude of the contraction was thus associated with the degree of baking and with the degree of starch granule destructuration.     

Slow responses of understory plants of maple-dominated forests to white-tailed deer experimental exclusion

We examined the response of understory plants in mature maple-dominated forests of southern Québec, Canada, following about 30 years of high deer densities, using a deer exclosure experiment. An exclosure and a paired control of 625 m² each were established on six sites in 1998. An exclosure and a paired control of 16 m² were added at each of the same sites in 2003 but under a recent canopy gap to determine if light could enhance plant responses. We measured plant richness and abundance, and aboveground biomass of different plant groups for 8 years in the understory plots and for 3 years in the canopy gaps. Four herbaceous species were also monitored individually in the same plots. No significant differences between treatments were found in plots under forest cover, except for lateral obstruction at 0–50 cm height which was higher in the exclosures. Under canopy gaps, however, tree seedling and total plant abundance were higher in deer exclosures than in control plots. Trillium erectum recovered partially as individuals were taller, had larger leaves and more frequently produced a flower or a fruit in the absence of deer browsing under forest cover. To a lesser extent, Erythronium americanum and Maianthemum canadense also exhibited signs of recovery but were still at the single-leaf stage after 8 years of recovery. In general, the different plant groups exhibited little recovery following deer exclusion, possibly because of the low light levels that prevailed in the understory of undisturbed maple-dominated forests. The higher latitude of the present study could also contribute to the slow recovery rates of the different groups of plants compared to studies conducted in northeastern USA. Variability among sites and years had an effect on detection of statistically significant differences. Trends are however appearing over time, suggesting that many understory plants are recovering very slowly following deer exclusion. Our results emphasize the importance of studying large herbivore–forest interactions on different groups of plants, but also on specific species, and under different latitudes to be fully understood.     

Medicinal understory herbaceous species cultivated under different light and soil conditions in maple forests in southern Québec,Canada

Many northern hardwood understory plants have medicinal properties but their cost of production under conventional cultivation practices is fairly high. Therefore wild harvesting continues putting the natural populations at risk. Their cultivation in a forest farming system seems a promising alternative. This study was aimed at assessing the impact of canopy opening and soil fertility on growth and active component production of four medicinal plants: black cohosh (Actaea racemosa), wild ginger (Asarum canadense), blue cohosh (Caulophyllum thalictroides) and bloodroot (Sanguinaria canadensis). Rhizome sections were planted in two sugar maple forests. Mortality and total leaf area were monitored during 3 years, while subplots were harvested at the end of the second year for biomass and active component analyses. Multiple regressions indicated that all species responded more to acidity related elements (pH, Al, Al + H, Fe, Zn) than to soil fertility (Ca, K, Mg, P, C/N, base saturation and cation exchange capacity). This suggests that adjusting the pH by liming could be appropriate. Growth increased with irradiance, except for blue cohosh, indicating that forest openings could also be part of an appropriate forest management plan for their cultivation. While active component concentrations of rhizomes and roots increased in conditions that negatively affected growth, such as low pH, soil fertility or light availability, their total active component content exhibited responses that were similar to those of the growth variables. Thus, it seems that soil and light conditions that favour the growth of these medicinal plants also favour their total yield in active components.     

Spatial heterogeneity of soil organic carbon in tree-based intercropping systems in Quebec and Ontario,Canada

Land use affects the carbon sequestration potential of soils across landscapes. Tree-based intercropping (TBI) systems where annual crops are grown between established tree rows are expected to exhibit spatial heterogeneity in the soil organic carbon (SOC) content due to differences in carbon input and decomposition rates of litter from trees and herbaceous plants. This study aimed to quantify variability in the SOC of TBI systems, compare the SOC content of TBI and nearby conventional agroecosystems, and determine if SOC was related to soil fertility. The TBI research sites were established 4 years (St. Paulin and St. Edouard, Quebec, Canada), 8 years (St. Remi, Quebec, Canada) and 21 years (Guelph, Ontario, Canada) before soil samples were collected for this study. The SOC content was greater within 0.75 m of the tree row than in the intercropped space at the St. Edouard and St. Remi sites. At the Guelph site, the SOC was spatially heterogeneous in plots with Norway spruce (Picea abies L.) but not hybrid poplar (Populus deltoides × P. nigra clone DN-177), probably due to litterfall distribution. Formerly a tree plantation, the TBI system at St. Remi contained 77% more SOC than a nearby conventional agroecosystem, while there was 12% more SOC in the TBI system than the conventional agroecosystem at Guelph. There was no difference in the SOC content of 4-year old TBI sites and nearby conventional agroecosystems. However, an increase in SOC at all TBI sites was positively related to the plant-available N concentrations, indicating the benefit of temperate TBI systems for soil fertility.     

Spatial structure of shell polychromatism in <Emphasis Type="Italic">Cepaea hortensis</Emphasis> in relation to a gradient of landscape fragmentation in Western France

Because of their highly polymorphic shell patterns, Cepaea land snails have been the subject of numerous studies in ecological genetics. Here, we investigated the spatial structure of polychromatism in Cepaea hortensis in agricultural landscapes with zones from low to high hedgerow densities. Our main purpose was to search for a relationship between landscape composition and spatial structuring of chromatism. Despite significant spatial heterogeneity in the three landscapes sampled, only the high hedgerow density landscape showed a significant spatial structuring of shell polymorphism. In order to understand this result, an investigation of daily movement patterns in relation to habitat form was carried out on a mark-release experiment under semi-artificial conditions. This experiment revealed a strong influence of a linear corridor on snail dispersal. In the field, spatial heterogeneity of shell polymorphism, related to the effects of genetic drift, was shaped by restricted dispersal in narrow corridors. In the more enclosed one, i.e. where hedgerow density was the highest, the significant spatial structure we detected involved a balance between local genetic drift and environmentally mediated gene flow. This isolation-by-distance pattern resulted from direct gene exchange through fields between neighbouring populations. When applying landscape distances based on hedgerow length, no significant spatial correlation with polychromatism was found. In the more fragmented sites, random genetic drift seemed to be the prevailing force and, at the scale of the whole sampled area, selective pressures potentially interfere with these genetic drift-dispersal events.     

Quantitative relationships between Ostrinia nubilalis activity and deoxynivalenol contamination in French maize

We investigated the indirect effect of an insecticide spray against the European Corn Borer (Ostrinia nubilalis Hübner; Lepidoptera: Crambidae) on mycotoxin contaminations of grain maize at the harvest stage. Between 2004 and 2009, 45 paired plots comparing insecticide treatment with untreated control were studied in Alsace administrative region, in the northeast of France. An average reduction of 78% in O. nubilalis larval densities was observed in insecticide-treated plots compared with control plots. Mean levels of deoxynivalenol mycotoxin in harvested grain were significantly reduced from 849 ppb in the control samples to 152 ppb in the insecticide-treated samples. A statistical modelling approach involving Generalized Linear Models (GLMs) was employed to identify and rank the associated variables for damage and pest density on different plant parts, on deoxynivalenol levels in harvested grain at harvest. The modelling revealed that the occurrence and the density of O. nubilalis larvae in maize stalks and in ears are the best indicators for deoxynivalenol contamination. The identification of these deoxynivalenol contamination risk factors, along with other factors such as genetic background, harvest date and crop rotation allows improvement of the risk assessment and risk forecasting in maize crops in order to manage crop safety and maintain maize deoxynivalenol mycotoxin levels below the European Regulation (EC) No. 1126/2007 threshold.     

In situ imaging highlights local structural changes during heating: the case of meat

Understanding and monitoring deformation and water content changes in meat during cooking is of prime importance. We show the possibilities offered by nuclear magnetic resonance imaging (MRI) for the in situ dynamic measurement of deformation fields and water content mapping during beef heating from 20 to 75 °C. MRIs were acquired during heating, and image registration was used to calculate the deformation field. The temperature distribution in the sample was simulated numerically to link structural modifications and water transfer to temperature values. During heating, proton density decreases because of a magnetic susceptibility drop with temperature and water expulsion due to muscle contraction. A positive relationship was found between local cumulative deformation and water content. This new approach makes it possible to identify the deformation field and water transfer simultaneously and to trace thermal history to build heuristic models linking these parameters.     

Seed phosphorus remobilization is not a major limiting step for phosphorus nutrition during early growth of maize

Phosphorus (P) is the least mobile nutrient in the soil as compared to other macronutrients and therefore frequently limits crop growth. During germination and early growth, seed‐phytate hydrolysis and seed‐P remobilization is the major P source for developing seedlings. The objective of this paper was to investigate whether seed‐P hydrolysis and remobilization of nonphytate P are sufficient for seedling P nutrition during early growth stages of maize. A large part of initial maize endogenous seed P reserves are mainly in the form of phytate. Till 70 cumulated degree days after sowing, nearly all the phytate (98%) was hydrolyzed and caused an increase in nonphytate P in seeds. Phytate hydrolysis and remobilization of nonphytate P was the main source of P supply for the newly growing seedlings and was not a limiting step for seedling P nutrition during the first four weeks of early growth.     

Almond agronomic response to long-term deficit irrigation applied since orchard establishment

This study assesses the long-term suitability of regulated (RDI) and sustained deficit irrigation (SDI) implemented over the first six growing seasons of an almond [Prunus dulcis (Mill.) D.A. Webb] orchard grown in a semiarid area in SE Spain. Four irrigation treatments were assessed: (i) full irrigation (FI), irrigated to satisfy maximum crop evapotranspiration (100% ET_c); (ii) RDI, as FI but receiving 40% ET_c during kernel-filling; (iii) mild-to-moderate SDI (SDI_mm), irrigated at 75–60% ET_c over the entire growing season; and (iv) moderate-to-severe SDI (SDI_ms), irrigated at 60–30% ET_c over the whole season. Application of water stress from orchard establishment did not amplify the negative effects of deficit irrigation on almond yield. Irrigation water productivity (IWP) increased proportionally to the mean relative water shortage. SDI_ms increased IWP by 92.5%, reduced yield by 29% and applied 63% less irrigation water. RDI and SDI_mm showed similar productive performances, but RDI was more efficient than SDI_mm to increase fruiting density and production efficiency (PE). We conclude that SDI_ms appears to be a promising DI option for arid regions with severe water scarcity, whereas for less water-scarce areas RDI and SDI_mm behaved similarly, except for the ability of RDI to more severely restrict vegetative development while increasing PE.