Role of environmental filtering and seed source availability in natural regeneration processes following large-scale disturbances in mountain forests

European Journal of Forest Research - The relative importance of environmental factors and species pool in natural regeneration processes is still intensively disputed. Is environmental filtering...     

Chemical composition of natural and polyphenol-free apple pomace and the effect of this dietary ingredient on intestinal fermentation and serum lipid parameters in rats

Unprocessed pomace containing 61% of dietary fiber (DF) and 0.23% of polyphenols (PP) and ethanol- or ethanol/acetone-extracted pomaces containing 66% DF and 0.10% PP and 67% DF and 0.01% PP, respectively, were subjected to a 4 week study in rats. The aim of the study was assessing the advantages of dietary supplementation with the above pomaces. To measure the animal response to dietary treatments, parameters describing cecal fermentation and lipoprotein profile were assessed. The dietary use of 5% unprocessed pomace caused an increase in cecal short-chain fatty acid (SCFA) production and a decrease in blood triacylglycerols, leading to a drop in serum atherogenic index. Ethanol-extracted pomace increased the glycolytic activity of cecal microbiota and decreased cecal branched-chain fatty acid production, whereas acetone extraction led to lower cecal ammonia concentration, decreased colonic pH value, and higher HDL/total cholesterol ratio. The variations in the atherogenic index indicate flavonoids as the key pomace component in relation to blood lipid profile benefits.     

Riboflavin content in the coelomocytes of contrasting earthworm species is differentially affected by edaphic variables including organic matter and metal content

The riboflavin content in extruded coelomocyte lysates derived from Dendrodrilus rubidus may serve as a sensitive bioindicator of soil metal pollution: the vitamin (B2) content has previously been found to be high in worms from unpolluted soil but low in worms inhabiting Zn/Pb mine soils, aerially deposited Ni-contaminated soil, and in worms experimentally transferred from clean soil to the metalliferous field soils. The aim of the present work was to extend these observations by comparing the number and riboflavin composition of coelomocytes retrieved from three lumbricid species (Allolobophora chlorotica, Dendrobaena veneta, Eisenia andrei) after 4-week exposures to an unpolluted commercial soil, two geochemically contrasting unpolluted field soils, and two different Zn/Pb/Cd-polluted soils from the Bukowno district in South Poland. Whilst eco-physiologically contrasting, these three earthworm species share the trait of possessing relatively high numbers of eleocytes, a category of immune-competent coelomocyte rich in autofluorescent riboflavin. Spectroflurometric analysis indicated that coelomocyte riboflavin content in worms maintained in strongly metalliferous soils or in unpolluted sandy-clay and loamy-sand soils was increased in coleomocytes from epigeic D. veneta and E. andrei species, whilst was decreased in endogeic A. chlorotica. In conclusion, the riboflavin content of earthworm coelomocytes is affected in species-specific ways by edaphic variables, including organic matter and metal pollution.     

Sea anemone genome reveals ancestral eumetazoan gene repertoire and genomic organization

Sea anemones are seemingly primitive animals that, along with corals, jellyfish, and hydras, constitute the oldest eumetazoan phylum, the Cnidaria. Here, we report a comparative analysis of the draft genome of an emerging cnidarian model, the starlet sea anemone Nematostella vectensis. The sea anemone genome is complex, with a gene repertoire, exon-intron structure, and large-scale gene linkage more similar to vertebrates than to flies or nematodes, implying that the genome of the eumetazoan ancestor was similarly complex. Nearly one-fifth of the inferred genes of the ancestor are eumetazoan novelties, which are enriched for animal functions like cell signaling, adhesion, and synaptic transmission. Analysis of diverse pathways suggests that these gene "inventions" along the lineage leading to animals were likely already well integrated with preexisting eukaryotic genes in the eumetazoan progenitor.     

In vitro selection of strawberry (Fragaria × ananassa Duch.) clones tolerant to salt stress

The method of in vitro selection for increased salt tolerance at the seed germination and early growth phase of strawberry seedlings is proposed. Clone Pau/27 was selected on medium containing 200 mM of NaCl from population obtained by free pollination of cv. ‘Paula2019;. Subsequently, on the same medium 18 salt tolerant clones were attained from the population of seeds collected from self pollinated Pau/27 plants. In the next step we examined the influence of a mild salt stress (75 mM of NaCl) on vegetative growth parameters of selected clones and two cvs.; ‘Paula2019; and ‘Senga Sengana’. All materials in the study on the basis of calculated indexes were divided into four groups differing in reaction to salt. First group (clustered together cv. ‘Paula’, Pau/27 and three second generation clones: Pau/27/11, Pau/27/24, Pau/27/30) represents sensitive genotypes. Second group, including ‘Senga Sengana’, Pau/27/06, Pau/27/10, Pau/27/12, Pau/27/13, Pau/27/15, Pau/27/18, Pau/27/20, Pau/27/21, Pau/27/26, Pau/27/27, Pau/27/31 and Pau/27/32 was designated tolerant. Third group contains only one highly tolerant clone Pau/27/08. The last group comprises two highly sensitive clones (Pau/27/01 and Pau/27/03). This revised version was published online in August 2006 with corrections to the Cover Date.     

Regional impacts of abolishing direct payments: An integrated analysis in four European regions

The direct payment system of the Common Agricultural Policy (CAP) provides income transfers to European farmers. Recently, several countries including England and Sweden have advocated the elimination of direct payments after 2013. The extent to which an elimination of direct payments would affect the land use dynamics in Europe including impacts on structural change and the environment has not been addressed in the existing literature. In this paper, we combine participatory methods, to analyze regional preferences for functions and effects of agriculture, and farm-level modeling, to assess the impacts of such a policy change on farm structures and land use intensities in four European regions located in Germany, Denmark, Italy and Poland, each with different socio-economic and biophysical characteristics. In each region, the entire farm population consisting of different farm types with different production orientations and land management types was modeled under the presence and absence of direct payments using a combination of agent-based and bio-economic modeling. We found that the initial characteristics of the regions, such as the historical farm structure and regional site conditions, greatly influence the impact of direct support elimination and cause regionally different development trends. The results for the four regions were summarized in four specific storylines that emphasize how much the diversity of European regions matters for future policy decisions. An explicitly regional focus is, therefore, argued to be crucial to complement future policy analysis.     

Interactions betweenPotato leafroll virus and potato plants and their implications for assessment of infection resistance

The effects of Potato leafroll virus (PLRV) isolates and inoculation method on the resistance to PLRV in potato clones and cultivars were investigated. In the season of inoculation, aphid inoculation resulted in higher proportions of infected plants and higher virus concentration in infected plants, as compared to graft inoculation. In these respects, grafting showed superiority over aphid inoculation in the tuber progeny of inoculated plants, though distinct dominance of aphid inoculation was observed for some tested clones. This leads to the conclusion that both methods should be applied as complementary tests for the efficient selection of highly resistant potato clones. For inoculations, two isolates of PLRV were applied, and one of them, isolate L7, was routinely used in screening breeding materials for resistance to the virus. The second isolate originated from plants of the highly resistant clone DW84-1457, which were incidentally infected with PLRV. The virus isolated from these plants was able to infect only specific clones, which were resistant to isolate L7. At the same time, potato clones with resistance derived from a source different from that present in DW84-1457, and standard susceptible and resistant cultivars, showed generally lower infection ratings after inoculation with the new isolate. This result suggests that the isolates may be different strains of PLRV. It is possible that under the strong selection pressure of resistance genes present in clone DW84-1457, a new isolate I-1457 could evolve the ability to overcome resistance to infection controlled by these genes.     

The influence of temperature on transmission of potato leaf roll virus byMyzus persicae Sulz

Summary Potato leaf roll virus (PLRV) was usually better transmitted byMyzus persicae from source plants kept during the pre-acquisition period at 12°C than from those kept at 26°C. Significantly more plants became infected when PLRV was acquired or inoculated at 26°C than at 12°C. The effect of temperature during the acquisition feeding period was found to be greater than that of temperature during the inoculation feeding period. PLRV was most frequently transmitted when it was both acquired and inoculated at 26°C.

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Zusammenfassung Der Einfluss der Temperatur auf die übertragung des Kartoffel-Blattrollvirus (PLRV) durchMyzus persicae wurde in drei Perioden vor der Infektion der Pflanzen mit diesem Virus ermittelt: Vegetationsperiode vor Aufnahme durch die Virusquellen, Periode w?hrend der Virusaufnahme und der Inokulationsperiode. Die Untersuchungen wurden in temperaturkonstanten Kammern und im Gew?chshaus mit Pflanzen der Kartoffelsorte Osa als Quelle mit ausgew?hlten PLRV-Isolaten durchgeführt. Das Virus wurde aufPhysalis floridana und Kartoffelsorten unterschiedlicher Anf?lligkeit übertragen. Die H?ufigkeit der PLRV-übertragung durchM. persicae sank mit ansteigender Temperatur, zu welcher die Quellenpflanzen in der Periode vor der Virusaufnahme aufwuchsen (Abb. 2 und 3), obwohl dieser Effekt ausgeschaltet werden konnte, wenn das Virus durch die Blattl?use bei h?herer Temperatur aufgenommen wurde (Abb. 2). Die H?ufigkeit der PLRV-übertragung durch Blattl?use war nach einer Aufnahmeperiode bei 26°C signifikant gr?sser als bei 12°C (Abb. 2 bis 4). Der Einfluss h?herer Temperatur k?nnte stark genug sein, die Unterschiede in der PLRV-übertragung durch den Einfluss auf die Quellenpflanzen in der Vor-Aufnahmezeit zu eliminieren oder zu vermindern (Abb. 2). ?hnliches zeigte sich bei zunehmendem Alter der Quellenpflanzen (Abb. 1). Eindeutig mehr Pflanzen wurden infiziert, wenn PLRV bei 26°C anstatt 12°C inokuliert wurde (Abb. 3 und 4). Der Einfluss der Temperatur war in der Aufnahmeperiode gr?sser als in der Inokulationsperiode. Eine signifikant gr?ssere Population vonP. floridana und/oder Kartoffelpflanzen wurden infiziert, wenn PLRV durchM. persicae bei 26°C aufgenommen und inokuliert wurde (Abb. 3 und 4). Darüberhinaus war der Einfluss h?herer Temperatur, w?hrend beider Aufnahmeperioden angewendet, günstiger für visuelle und serologische (ELISA) Differenzierung der resistenten und anf?lligen Kartoffeln, gemessen an der H?ufigkeit infizierter Pflanzen (Abb. 4).

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Résumé L'influence de la température sur la transmission du virus de l'Enroulement de la pomme de terre (VEPT) parMyzus persicae a été déterminée à trois périodes précédant l'infection des plantes par ce virus: période de végétation des plantes sources de virus avant acquisition (pré-acquisition), période d'acquisition, période d'inoculation. Les recherches ont été réalisées dans des salles à température contr?lée et en serre: des pommes de terre du cultivar Osa, infectées par des isolats sélectionnés de VEPT ont été utilisées comme plantes sources. Le virus a été transmis àPhysalis floridana et à des cultivars de pomme de terre de différentes sensibilités à l'infection par le VEPT. La fréquence de transmission du VEPT parM. persicae décro?t avec l'augmentation de la température à laquelle les plantes sources de virus ont été cultivées lors de la période de pré-acquisition (Figs 2 et 3), bien que cet effet ait pu être éliminé quand le virus a été prélevé par les pucerons à température plus élevée (Fig. 2). La fréquence de transmission du VEPT par les pucerons a été significativement plus grande après une période d'acquisition à 26° qu'à 12°C (Figs 2–4). L'effet de la température la plus élevée a pu être suffisamment fort pour supprimer ou réduire les différences de transmission du VEPT causées par l'effet de la température sur les plantes sources lors de la période de pré-acquisition (Fig. 2) ou par l'augmentation de l'age des plantes sources (Fig. 1). Un nombre significativement plus grand de plantes a été infecté quand le VEPT était inoculé à 26°C qu'à 12°C (Figs 3 et 4). L'effet de la température s'est avéré avoir une importance plus grande pendant la période d'acquisition que pendant la période d'inoculation. Une proportion significativement plus élevée deP. floridana et/ou de plants de pomme de terre a été infectée quand le VEPT était à la fois acquis et inoculé parM. persicae à 26°C (Figs 3 et 4). De plus, une température plus élevée appliquée pendant les deux périodes d'alimentation des pucerons s'est montrée plus favorable pour différencier visuellement et sérologiquement (ELISA) les pommes de terre résistantes, modérément résistantes et sensibles, lorsqu'on se base sur la fréquence des plantes infectées (Fig. 4).

     

Altitudinal variability of stand structure and regeneration in the subalpine spruce forests of the Pol’ana biosphere reserve,Central Slovakia

The structure of natural subalpine spruce forest in the Zadná Pol’ana massif of the Western Carpathians was analysed. We focused on the variability of different aspects of stand structure, tree decay and regeneration processes in altitudinal gradient. We used systematic sampling, covering an area of 2 km², to detect even subtle changes in stand structure within one forest type over a range of less than 200 m in elevation. Mean stand density was 290 trees (>7 cm DBH) per hectare, average basal area was 41 m² ha⁻¹, and the volume accumulation in living trees amounted to 500 m³/ha⁻¹. Stand volume decreased by more than 50% between 1,260 and 1,434 m a.s.l. This means for an increase of altitude of 100 m that stand volume decreased by nearly 200 m³. Neither stand density nor basal area was related to elevation. Maximum tree height was strongly correlated to elevation, and it decreased on average by 6 m for each 100 m increment of altitude. No significant changes in the maximum spruce diameter were recorded in relation to the elevation gradient. Spatial distribution of trees was biased toward regularity at lower altitudes. Tree clustering increased with increasing altitude. The stock of coarse woody debris (CWD) decreased slightly along the altitudinal gradient, but changes were not significant. Density of spruce saplings and their number growing on CWD significantly increased across the elevation gradient. Despite the fact that the analysed forest tract was relatively large, highly variable in respect to environmental factors, and that stand volume, spatial structure, and tree height displayed strong variability along the elevation gradient, the diameter structure of stands and regeneration measures were uniform. Our results suggest that the recruitment of new trees in the Zadná Pol’ana subalpine spruce forest is not temporally continuous even at a scale of several square kilometres.