First report of Sydowia polyspora causing disease on Pinus pinea shoots

The fungus Sydowia polyspora is frequently isolated from conifers worldwide and is considered a pathogen on several hosts. Stone pine (Pinus pinea) is one of the most important forestry species throughout the Mediterranean basin due to the value of the edible pine nut. Stone pines showing tip dieback, needles with tan‐ to yellow‐coloured lesions and shoot death, observed in stands in Portugal, were sampled for analysis. Fungal colonies covered with cream‐coloured spore masses, were consistently obtained. Morphological and phylogenetic analyses of the ITS rDNA region enabled identification of these isolates as S. polyspora. Inoculation tests showed that the fungus caused lesions on excised P. pinea shoots. The symptoms observed might have a negative effect on pine nut production, and thus, evaluation of the impact of this disease is of relevance to future research. This paper is the first to report S. polyspora causing disease on P. pinea.     

Which are the best environmental conditions for catching the beach‐seine target species? A Portuguese case study

The beach‐seine fishery is a commercial fishing activity on the Portuguese coast, with reports dating as far back as the early 15th century. The main target species of this fishery are small pelagic fish such as Atlantic chub mackerel, Atlantic horse mackerel and sardine. To identify the best conditions for fishing the target species, catches of beach seine (2007–2017) were used and generalized linear models were applied, using a binomial and gamma distributions. The logistic model explained between 36.3% and 45.7% of the catches variability; the gamma model explained 9.1% and 46.9% of the catches variability, being month and wind direction the best covariates for the occurrence and/or abundance of the three small pelagic fishes in analysis. If the effort is directed to the days that meet the conditions found for each species (sardine: between May and October, wind NW, daytime; Atlantic horse mackerel: May, NW/NE wind, 800 m from the coastline; Atlantic chub mackerel: from July to August, NW moderate wind), a reduction in bycatch and discards can be achieved. This approach can have a positive economic and social impact, since it provides information for turning fisheries more efficient.     

Soil macropore dynamics affected by tillage and irrigation for a silty loam alluvial soil in southern Portugal

Soil tillage can have a significant effect on soil porosity and water infiltration. This study reports field measurements of near saturated hydraulic conductivity in an undisturbed soil under two tillage treatments, conventional tillage (CT) and minimum tillage (MT). The objective was to determine effective macro and mesoporosities, porosity dynamics during the irrigation season, and their contribution to water flow. Field observations were performed during the 1998 maize (Zea mays L.) cropping season in an Eutric Fluvisol with a silty loam texture, located in the Sorraia River Watershed in the south of Portugal. Infiltration measurements were done with a tension infiltrometer. At each location an infiltration sequence was performed corresponding to water tensions (φ) of 0, 3, 6 and 15 cm. Five sets of infiltration measurements were taken in both treatments in the top soil layer between May and September. One set of measurements was done at the depth of 30 cm at the bottom of the plowed layer in the CT plot. After 5 years of continuous tillage treatments the results show that regardless of the tillage treatment, saturated conductivity values K(φ₀) were several times larger than near saturation conductivity K(φ₃). This indicates that subsurface networks of water conducting soil pores can exist in both CT and MT maize production systems. In CT, the moldboard plow created macro and mesoporosity in the top soil layer while breaking pore continuity at 30 cm depth. This porosity was partially disrupted by the first irrigation, resulting in a significant decrease of 45% in the macropore contribution to flow. Later in the season, the irrigation effect was overlaid by the root development effect creating new channels or continuity between existing pores. In MT macroporosity contribution to flow did not show significant differences in time, representing 85% of the total flow. In both the treatments, macropores were the main contributing pores to the total flow, in spite of the very low macroporosity volumes.     

Recovering Portuguese Rice Landraces by Marker-Assisted Selection

Rice （Oryza sativa L.） was domesticated in Asia and brought to Europe （Mediterranean region） by returning members of Alexander the Great＇s expedition to India （324 B.C） （Khush, 1997）. In Portugal, rice was introduced by the Moors in the 10th century, and therefore has a long cultural tradition. Among the European countries, Portugal has the highest rice consumption per capita, with approximately 22.4 kg/capita/year, while the second country, Spain, only consumes 10.4 kg/capita/year （data from http：//www.fao.org referring 2004）. In 2005, the total rice area harvested was 23 060 hm2, distributed on the four main river beds： Mondego, Tejo, Sado and Sorraia. Presently Portugal produces nearly 56% of the internal demands, to meet the national needs, importation reached 6.8 xl07 kg in the year 2005 （data from http：//ania.pt）. About 80 percent of the rice area in Portugal is cultivated with japonica varieties and the rest is cultivated with indica-like varieties. These indica-like varieties are being cultivated particularly in the Southern regions, with much acceptance by the farmers due to their higher yields. Presently all Portuguese commercial varieties are either from Italy or from overseas.     

Incorporation of trace elements on iron-rich concretions around plant roots of tagus estuary salt marsh (portugal)

Objective

The concentration gradients of solid Al, Fe, Mn, Zn, Cd, Pb, Cr and Ni in freshly formed concretions and in older concretions preserved in the sediment were evaluated in a millimetre resolution scale. These results provide a better understanding of the complex biogeochemical processes in the root-sediment system and elucidate the potentialities of marshes in the restoration of contaminated aquatic systems.

Methods

Tens (soll das vielleicht tonnes/tons heißen) of freshly formed concretions and preserved concretions were collected in the Rosário salt marsh. Each tubular structure and involving sediments were scraped in concentric layers of 2-mm thickness to form two sets of composite samples. The elemental composition of concretion and sediment samples were determined by atomic absorption spectrometry.

Results and Discussion

The sediment involving the concretions contained ～0.5 mmol g^-1 Fe, but concentrations increased towards the root up to 3.4 mmol g^-1 in 3-mm interval. Manganese, Zn, Cd and Pb exhibited similar radial distribution in both preserved and freshly formed concretions indicating that these metals remain in those structures with the age. Chromium and Ni showed a different pattern being lower in concretions with respect to involving sediments, and consequently, concretions do not act as a barrier for these elements. The estimated amount of Zn (59 tons), Pb (5 tons) and Cd (0.4 tons) retained in the concretions all over the Rosario salt marsh highlights the importance of these structures in sequestering metals.

Conclusions and Outlook

The sequestering may be particularly relevant in salt marshes located near urban and industrial zones, being areas working as a natural remediation system and contributing for the detoxification of aquatic environments and the well-being of coastal resources.

     

Precipitation and Erosivity in Southern Portugal: Seasonal Variability and Trends (1950–2008)

Southern Portugal experiences the lowest amounts of annual precipitation and the highest level of susceptibility to soil erosion, drought events and desertification phenomena in mainland Portugal. The first goal of this paper was to analyse spatial variability and trends in annual precipitation and erosivity in southern mainland Portugal for the period 1950/1951–2007/2008. The second objective was to evaluate seasonality in relation to precipitation distribution, erosivity and concentration over the same period and to evaluate and detect possible changes in the time trend for precipitation erosivity. In order to achieve these objectives, the annual and seasonal precipitation figures, corresponding to data from 90 rain gauges, were analysed and the Modified Fournier Index and Precipitation Concentration Index calculated for each station. The results obtained revealed distinct behaviour patterns for yearly precipitation, erosivity and concentration trends. Decreases in annual precipitation and erosivity figures accompanied by increases in precipitation concentration were found. Nevertheless, no generalised significant trends have been detected for these variables. In seasonal terms, there was a general trend towards an increase in amount, concentration and precipitation erosivity in autumn and summer, and a significantly reducing in winter. The increase in precipitation erosivity, particularly in the autumn, the most water‐erosive season, suggests a rising in potential soil erosion risk in southern Portugal. Copyright © 2014 John Wiley & Sons, Ltd.     

Sublethal infection of different pine species by the pinewood nematode

Bursaphelenchus xylophilus, the pinewood nematode and causal agent of pine wilt disease (PWD), is a globally destructive pine pest. PWD is favoured by high temperatures and drought, but B. xylophilus can also persist in symptomless hosts in areas not prone to PWD. We compared seedlings of different Pinus species that were inoculated with B. xylophilus when well-watered and under moderate temperatures, conditions that favour sublethal infections. We compared isolates of B. xylophilus in south-west Europe (Portugal) and south-east USA (Louisiana). P. pinea, P. pinaster, and P. radiata were challenged in both areas with inoculations of local B. xylophilus. P. sylvestris in Portugal and P. palustris in Louisiana were also tested. Seedling mortality was low, as expected, but nematode establishment was common. There were higher nematode densities and more damage in seedlings of P. sylvestris and P. radiata, followed by P. pinaster, with P. pinea and P. palustris proving to be more tolerant. Life history of hosts was a better predictor of resistance to B. xylophilus than geographical origin, even under sublethal conditions. Fast-growing species (P. radiata and P. pinaster) appeared most likely to be symptomless carriers in areas not prone to the development of PWD. Cold-adapted species (P. sylvestris) may still be suitable hosts for the pathogen, even at the sublethal conditions of their distribution areas. There were more nematodes per gram of host using nematode isolates from Portugal. Nonetheless, our results opposed the hypothesis that North American pinewood nematodes have such low virulence that they are obligatorily saprophytic.     

Variation in fish assemblages across dry-season pools in a Mediterranean stream: effects of pool morphology, physicochemical factors and spatial context

Pires DF, Pires AM, Collares-Pereira MJ, Magalhães MF. Variation in fish assemblages across dry-season pools in a Mediterranean stream: effects of pool morphology, physicochemical factors and spatial context. Ecology of Freshwater Fish 2010: 19: 74–86. © 2009 John Wiley & Sons A/S
Abstract –  Knowledge of patterns of refuge use by fish is critical for maintaining biodiversity in drought-prone streams. In this study, the fish assemblages of 21 dry-season pools in a Mediterranean stream were characterised and related to three sets of factors reflecting pool morphology, physicochemistry and spatial context. Fish were associated with the three sets of variables, with variation partitioning indicating that overall species richness and abundance were primarily related to pool morphology but relative species abundances were mainly associated with physicochemical contexts. In general, species richness was the highest but overall fish abundance was the lowest in large pools. Pools well shaded by riparian canopy held the highest richness and abundance of native fish, but relative species abundances and assembly structure varied among pools contingent on canopy cover, substrate composition and spatial location. These results suggested that conservation of fish diversity in Mediterranean streams requires networks of pools with diverse sizes and physicochemical contexts.     

NPK farm-gate nutrient balances in dairy farms from Northwest Portugal

Farm-gate nutrient balances (N, P and K) were analysed in three groups of dairy farms from NW Portugal – medium, intensive and very intensive farms – during 3 consecutive years, 2003, 2004 and 2005. Results showed that the N surplus per hectare with values between 200 and 850 kg N ha⁻¹ was positively correlated with the milk production per ha and the stocking rate of the farm, whereas the P and K surpluses showed fewer variations between groups. In all farms the main inputs were the mineral fertilizers and the feed concentrates whereas milk was the main output. Farmers involved in the study were advised in terms of nutrient management and significant decreases in the nutrient surpluses were observed during the 3 years study, mainly due to a decrease of the inputs, namely fertilizers. We conclude that advisory campaigns among farmers are efficient to reduce the nutrient surpluses. The N losses via NH₃ emissions at farm scale were also estimated accordingly to IPCC emission factors and it appeared that such losses were significant and had to be considered together with the nutrient surpluses when strategies to enhance nutrient management are defined. On average, higher N surplus per hectare were observed in the studied dairy farms from NW Portugal relatively to other European regions, but NW Portugal present lower N surplus per production unit (kg milk) as well as higher N efficiency. Nevertheless, a target limit of 450 kg N ha⁻¹ for N surplus should be easily reached as a first step by most of the farms of NW Portugal by improving nutrient management at farm scale. However, more efforts will be necessary to reduce NPK surplus and NH₃ emissions to the mean values in a per hectare basis found in other European dairy regions with less intensive systems.     

提莫菲维小麦与葡萄牙野燕麦远缘杂交后代的SRAP分析

采用SRAP技术分析提莫菲维小麦与葡萄牙野燕麦远缘杂交后代的真实性及其特点。结果表明,22对SRAP引物中,20对引物在双亲间扩增出多态性条带,其多态性比率为73.81%。me4-em1、me3-em5、me4-em3和me3-em3四对引物在提莫菲维小麦与葡萄牙野燕麦杂交F3株系中扩增出双亲特异带,表明该F3株系具有双亲的遗传物质,该F3株系是提莫菲维小麦和葡萄牙野燕麦成功属间杂交的真实杂种后代。在F3株系的扩增结果中部分双亲带型消失,并且提莫菲维小麦消失的带数远少于野燕麦的;同时有非父母标记新带型出现。杂种后代DNA序列的这种变化可能有利于新形成异源多倍体小麦的快速进化、遗传协调和遗传稳定性。