Search results for "gum"

Inhibition of NO Biosynthetic Activities during Rehydration of Ramalina farinacea Lichen Thalli Provokes Increases in Lipid Peroxidation

2019

Lichens are poikilohydrous symbiotic associations between a fungus, photosynthetic partners, and bacteria. They are tolerant to repeated desiccation/rehydration cycles and adapted to anhydrobiosis. Nitric oxide (NO) is a keystone for stress tolerance of lichens

Reply from m. Heino, j.a.j. Metz and v. Kaitala.

1998

Eva Kisdi clarifies the relationships between frequency dependence, optimization and ESSs. We basically agree with all her comments. However, some further clarification may be useful.In the first paragraph of Kisdi's letter, ESSs and optimal strategies are seemingly opposed by saying that `finding an optimal strategy is a considerably stronger result than finding an ESS'. Although this statement is factually correct, it might engender a suggestion that is slightly wrong. Conceptually, ESSs are always primary: only ESSs matter from the viewpoint of long-term evolution. Optimization is secondary only, and must be justified by an ESS argument that explicitly accounts for the ecology in which t…

Net ammonification as influenced by plant diversity in experimental grasslands

2012

Abstract Previous plant diversity experiments have mainly reported positive correlations between diversity and N mineralization. We tested whether this relationship can be explained by plant diversity-induced changes i) in the quantity or quality of organic matter or ii) in microclimatic conditions of central European grassland mixtures. We measured ex-situ net ammonification in a laboratory incubation of aboveground plant material and soil sampled in differently diverse plant mixtures. Secondly, in-situ net ammonification was assessed in a field incubation with mineralization cores containing standardized material in four treatments: soil only (control), and soil mixed with field-fresh pla…

Drivers of Spruce Bark Beetle (Ips typographus) Infestations on Downed Trees after Severe Windthrow

2020

Research Highlights: Bark beetles are important agents of disturbance regimes in temperate forests, and specifically in a connected wind-bark beetle disturbance system. Large-scale windthrows trigger population growth of the European spruce bark beetle (Ips typographus L.) from endemic to epidemic levels, thereby allowing the killing of Norway spruce trees over several consecutive years. Background and Objectives: There is a lack of evidence to differentiate how outbreaks are promoted by the effects of environmental variables versus beetle preferences of trees from endemic to outbreak. However, little is known about how individual downed-tree characteristics and local conditions such as tre…

Potential Solar Radiation as a Driver for Bark Beetle Infestation on a Landscape Scale

2019

In recent decades, Norway spruce (Picea abies L. Karst.) forests of the High Tatra Mountains have suffered unprecedented tree mortality caused by European spruce bark beetle (Ips typographus L.). Analysis of the spatiotemporal pattern of bark beetle outbreaks across the landscape in consecutive years can provide new insights into the population dynamics of tree-killing insects. A bark beetle outbreak occurred in the High Tatra Mountains after a storm damaged more than 10,000 ha of forests in 2004. We combined yearly Landsat-derived bark beetle infestation spots from 2006 to 2014 and meteorological data to identify the susceptibility of forest stands to beetle infestation. We found that digi…

Influence of shear rate and concentration ratio on viscous synergism. Application to xanthan—Iocust bean gum— NaCMC mixtures Influencia de la velocid…

2000

A method is described that allows the development of an empirical approach to quantify synergistic interactions and their variations with shear rate. The approach is based on the definition of a viscous synergism index, Iv. The method is applied to xanthan-locust bean gum gels, and an equation is developed for relating the synergism index to shear rate, γ, and the locust bean gum/xanthan gum concentration ratio, z. The value of at which that function has a maximum, IMV, is calculated. This value of z provided an estimation of the proportion of gums at which maximum synergism occurs. A decreasing exponential dependence of these IMV on γ is shown. The influence of the addition of a fixed pro…

From a Crisis Discipline Towards Prognostic Conservation Practise: An Argument for Setting Aside Degraded Habitats

2017

Phylogeography and Molecular Evolution of Potato virus Y

2012

Potato virus Y (PVY) is an important plant pathogen, whose host range includes economically important crops such as potato, tobacco, tomato, and pepper. PVY presents three main strains (PVYO, PVYN and PVYC) and several recombinant forms. PVY has a worldwide distribution, yet the mechanisms that promote and maintain its population structure and genetic diversity are still unclear. In this study, we used a pool of 77 complete PVY genomes from isolates collected worldwide. After removing the effect of recombination in our data set, we used Bayesian techniques to study the influence of geography and host species in both PVY population structure and dynamics. We have also performed selection and…

Interactive effects between diet and genotypes of host and pathogen define the severity of infection

2012

Host resistance and parasite virulence are influenced by multiple interacting factors in complex natural communities. Yet, these interactive effects are seldom studied concurrently, resulting in poor understanding of host-pathogen-environment dynamics. Here, we investigated how the level of opportunist pathogen virulence, strength of host immunity and the host condition manipulated via diet affect the survival of wood tiger moth Parasemia plantaginis (Arctidae). Larvae from “low cuticular melanin” and “high cuticular melanin” (considered as low and high pathogen resistance, respectively) selection lines were infected with moderately and highly virulent bacteria strains of Serratia marcescen…

The ongoing naturalisation of Eucalyptus spp. in the Mediterranean Basin: new threats to native species and habitats

2019

The genus Eucalyptus has been widely introduced into many regions of the world outside its native range and has become invasive in some Mediterranean biomes (e.g. in southern Africa and California). In the Mediterranean Basin and Europe, eucalypts were introduced at the end of the 18th century. However, natural regeneration events in these regions are recent in time and limited in terms of affected areas, except for the Iberian Peninsula. An updated overview about the natural spread of Eucalyptus species in Italy is still lacking. This paper aims to fill this knowledge gap, using both published data and unpublished field data regarding naturalisation events, with a specific focus on Sicily.…