Recent plant diversity changes on Europe's mountain summits

In mountainous regions, climate warming is expected to shift species' ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe's major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras' species richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (-1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region.     

Organic nitrogen mineralization in temperate humid-zone soils after two and six weeks of aerobic incubation

The N mineralization rate in 11 soils was studied by aerobic incubation at 28°C and at a moisture content of 75% of field capacity for 2 weeks (short term) and 6 weeks (medium term). Relationships between the N mineralization indices for each period were evaluated. Ammonification largely predominated during the first 2 weeks of incubation, whereas nitrification was the predominant process between weeks 2 and 6. The net N mineralized in the different soils varied from 0 to 2.85% of the organic N after 2 weeks of incubation and from 0.32 to 3.36% of the organic N after 6 weeks of incubation, the mean values for each period being 0.82 and 1.51% of the organic N, respectively. The quantities of NH _inf4 ^sup+ -N, NO _inf3 ^sup- -N, and total inorganic N produced and the percentage of organic N mineralized after 2 weeks of incubation were highly and positively correlated with the coresponding values after 6 weeks of incubation. These results showed that either length of incubation could be used to determine the potential N mineralization capacity of the soils. Information obtained from two incubation periods was largely supplementary for the kinetic study of N mineralization, ammonification, and nitrification; therefore a medium-term incubation with intermediate measurements of N mineralization over a short term may be more useful than a single measurement using either of the two incubation periods.     

The chemical composition of rainfall in a city of Northern Spain

A study was carried out over a period of 4 yr on precipitation in Santander, a coastal city with heavy rainfall in the north of Spain. An increase in acidity was found for the latter period studied, from April 1984 to April 1985, possibly due to a change in the meteorology of the area in this period. The correlations between the ions themselves, and with pollution from SO₂ and suspended particulate matter, as well as possible correlations with meteorological variables were analyzed using a multiple linear regression method. The influence of mid- and long-range transport of pollutants was also analyzed and found to be important when air masses come from highly industrialized zones both in Central Europe and in neighboring Spanish regions, although the contribution of the latter to total acid deposition is less owing to low frequency and the usually low volume of precipitation.     

Lowest effective and optimum poultry manure dose for reclaiming burnt soils: pot experiments

 Poultry manure (PM) efficacy to improve burnt soil revegetation was evaluated to determine the lowest effective and the optimum dose for burnt soil reclamation. A ¹⁵N-labelled forest soil (LS) was used to set up six treatments: LS, laboratory burnt LS (BLS) and BLS with PM dose equivalent to 1 (BLS+PM1), 2 (BLS+PM2), 4 (BLS+PM4) and 8 Mg dry PM ha^–1 (BLS+PM8). Ryegrass was sown in all treatments and grown for 3 months in a greenhouse. At harvesting, in the BLS treatment: (1) ryegrass yield was very low and the shoot:root ratio was high; (2) ryegrass-N content was closer to that of metabolic tissues or young plants than to structural tissues or mature plants; (3) most of the available endogenous N still remained in the soil inorganic N pool. These results suggested that, although seed germinated normally, ryegrass growth was stopped at an early developmental stage, producing small and weak plants unable to protect the burnt soil against erosion and to exploit the post-fire pulse of available N which, consequently, could be lost. The addition of PM to BLS increased the ryegrass yield from the lowest dose (BLS≈LS<BLS+PM1< BLS+PM2<BLS+PM4<BLS+PM8;P<0.05), the increase of the phytomass yield per Mg of added PM varying as follows: PM8<PM1≤PM4<PM2. The uptake of soil-available N by the ryegrass was greatly enhanced in all manured treatments, but the contribution of PM-N to plant nutrition was only significant in BLS+PM4 and BLS+PM8 treatments. The lowest effective PM dose was PM1 and the optimum cost-to-benefit ratio treatments were PM2 and PM4. Received: 31 January 2000     

Targeting arthropod subolesin/akirin for the development of a universal vaccine for control of vector infestations and pathogen transmission

Diseases caused by arthropod-borne pathogens greatly impact on human and animal health. Recent research has provided evidence that tick protective antigens can be used for development of vaccines with the dual target of controlling arthropod infestations and reducing their vector capacity for pathogens. As reviewed herein, protective antigens such as subolesin/akirin, which are highly conserved across vector species, show promise for use in development of a universal vaccine for the control of arthropod infestations and the reduction of pathogen transmission. However, further research is needed in critical areas towards achieving this goal.     

Is the ranking of poplar genotypes for leaf carbon isotope discrimination stable across sites and years in two different full-sib families?

Introduction   

Because of its vigorous growth, poplar can play an important role for sustainable production of woody biomass to cover renewable energy needs. Hence, the selection of suitable genotypes has to be based on relevant traits, among which intrinsic water use efficiency (W _i, estimated through leaf carbon isotope discrimination, Δ) may be a key trait. Besides a large genetic variation in Δ among the frequently planted poplar hybrids, the use of Δ in deployment or breeding programmes requires insights in the robustness of the genotype ranking for Δ across environments and years.     

Coffee ripeness monitoring using a UAV-mounted low-cost multispectral camera

Coffee beverage quality is highly correlated with the degree of fruit ripeness. In this sense, monitoring fruit ripeness is of utmost importance for harvest planning and, especially for obtaining high-quality beverages. Currently, this process is carried out through manual counts of unripe fruits, which is laborious and limited to a few plants within the field. This study aimed at evaluating the potential of a low-cost multispectral camera for coffee ripeness monitoring in the Zona da Mata region of Minas Gerais State, Brazil. For that, five fields of Arabica coffee with distinct characteristics were evaluated. During the coffee ripeness period, four flights were carried using a Phantom 4 Pro quadcopter equipped with a Mapir Survey 3W camera for imagery acquisition. After that, nine vegetation indices (VIs) were obtained. For the same dates, the percentage of unripe fruits was obtained using an irregular grid in all fields. The data was split into two ripeness classes: suitable for harvest (R) with?<?30% of unripe fruits; and not suitable for harvest (U), with?>?30% of unripe fruits. Then, a principal component analysis was used to infer the importance of the VIs to discriminate plants with unripe fruits from those with ripe fruits. The first two principal components explained?>?75% of the variance in the datasets from all coffee fields. The VIs were able to discriminate the ripeness classes (U and R) in most fields; however, their performance was directly influenced by the crop yield and canopy volume.

     

Optimisation of sample size for the detection of latent infection byRalstonia solanacearum in potato seed tubers in the highlands of Peru

Summary A sampling strategy was evaluated in the Andean highlands of Peru to optimise the detection ofRalstonia solanacearum in seed tubers harvested from symptomless crops. A sensitive and specific serological method developed at CIP was used to detect the pathogen in latently infected tubers. Optimum sample size was evaluated for symptomless crops after analysing various numbers of composite samples and using a binomial distribution model to calculate the detection probabilities.R. solanacearum was detected in all lots from fields with visible symptoms, so validating the detection technique. About half of the seed lots from apparently healthy fields at altitudes of up to 3,100 m were found positive for the pathogen.R. solanacearum was detected with 99% probability in samples of 350 tubers from seed lots from symptomless crops. This number of seed tubers could feasibly be processed in a seed-health test without incurring too high a cost for labour and materials.     

Niveles de diferenciación estructural alcanzados por las células prospectivas cardiacas cultivadas in vitro

A study of the ultrastructural characteristics of developing cardiac muscle cells from in vitro culture was carried out with die aid of tissues taken from the cardiogenic areas of 5 H. H. stage chick embryos. The characteristics of the developing cells were quite comparable to those developed in situ.