Effects of drought and rewatering on growth and transpiration in European beech seedlings late in the growing season     

Martina Hájíčková  Roman Plichta  Daniel Volařík  Roman Gebauer 《New Forests》2017,48(6):773-784

Drought stress is one of the most important environmental factors affecting plant growth and survival. To date, most studies aim at understanding of post-stress physiological and anatomical adaptation to drought stress; however only few studies focus on plant recovery. In the present study, transpiration, shoot water potential, and anatomical and morphological measurements were performed on 4-year-old European beech seedlings with fully developed leaves. The seedlings were exposed to three levels of soil water potential (well-watered, moderate drought stress and severe drought stress) and followed by rewatering under greenhouse conditions. Reduced transpiration rates were observed in the stressed seedlings as a response to drought stress, whereas anatomical and morphological variables remained unchanged. Three days after rewatering, transpiration rates in both moderately and severely stressed seedlings recovered to the levels of those of well-watered seedlings. Drought stress promoted leaf budding, resulting in higher shoot dry mass of stressed seedlings. Our findings indicate that anatomical and morphological adaptations of European beech seedlings to drought stress are visibly limited during late-season growth stages. These results will help us to further understand factors involved in drought adaptation potential of European beech seedlings faced with expected climate-related environmental changes. To complete our findings, further experiments on plant recovery from drought stress should be focused on different periods of growing season.  相似文献   

First report of Hymenoscyphus fraxineus on Fraxinus excelsior in Montenegro          下载免费PDF全文

I. Milenković  T. Jung  Z. Stanivuković  D. Karadžić 《Forest Pathology》2017,47(5)

During the monitoring of the mycological complex on different forest tree species in the Biogradska Gora National Park in north‐east Montenegro, symptoms indicative of ash dieback caused by Hymenoscyphus fraxineus were observed on young Fraxinus excelsior trees in the protected virgin forest, including dieback of plants and branches, wilting of leaves and shoots leading to a “flag‐like” habitus, premature shedding of leaves and longitudinal bark necroses. Using standard isolation methods, slow‐growing cultures with numerous phialides, typical of the asexual phase of the ash dieback fungus, were obtained. In addition, petioles with numerous characteristic apothecia were also recorded. This is the first report of H. fraxineus on common ash in Montenegro. Possible pathways of introduction and implications of the findings are discussed.  相似文献   

A quantitative analysis of food movement convergence in four Canadian provinces     

Ashley McInnes  Evan Fraser  Ze’ev Gedalof  Jennifer Silver 《Agriculture and Human Values》2017,34(4):787-804

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Radioactivity of Selected Agricultural Soils in Croatia: Effects of Soil Properties,Soil Management,and Geological Parameters     

Marko Šoštarić  Željka Zgorelec  Dinko Babić  Ivana Šestak  Ivica Kisić  Milan Mesić  Aleksandra Perčin 《Water, air, and soil pollution》2017,228(6):218

We present a study on the radioactivity of selected Croatian agricultural soils that vary considerably with respect to geological background; physical, chemical, and biological characteristics; soil type; land use; and soil management. Our investigation is focused on the main naturally occurring radionuclides (⁴⁰K, ²³⁸U, ²²⁶Ra, ²³²Th, ²³⁵U) and ¹³⁷Cs as the most threatening long-lived anthropogenic radionuclide. We find that the radioactivity level is not influenced by the application of different soil amendments, at least in moderate quantities, and that no effect of soil management can be detected as well. In contrast, geological and location-specific properties influence radionuclide content in soil, especially regarding the naturally occurring ones. Moreover, physical and chemical soil properties such as texture and soil adsorption complex, respectively, seem to be the main factors regarding fixation of ¹³⁷Cs in soil. Calculated dose rates for external exposure to the gamma radiation originating from soil have been found to be generally low, except for two locations where they are higher but not at a level that would lead to health problems for workers on the field.  相似文献   

Cabbage (Brassica oleracea var. capitata) as possible indicator of wartime metal and metalloid contamination in eastern Croatia (ICP-MS method)     

Dragana Jurić  Dinko Puntarić  Vlatka Gvozdić  Zdenko Lončarić  Ada Puntarić 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2017,67(3):270-277

Biomonitoring of the local population and environmental monitoring in eastern Croatia have revealed abnormalities in metal and metalloid distribution that could be related to war activities during the 1990s. The goal of this study was to determine whether there are differences in the concentrations of metals and metalloids by comparing locations of high and low-intensity combat activity; we also evaluated a possible connection between metal contamination in soil and in humans. We sampled 14 locations and measured the concentrations of 20 war related metals and metalloids (Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Li, Mg, Ni, Pb, Sb, Si, Sr, U, V and Zn). The results of principal components analysis showed two main clusters: locations Dopsin and Dalj (both characterized by high-intensity combat activity), where the concentrations of most elements (except Hg) were increased. Although the concentrations of metals and metalloids in cabbage samples collected in eastern Croatia did not exceed the maximum allowed values, the results of our study confirmed existance of environmental ‘hotspot’ with higher concentrations of war metals and metalloids. Our findings indicate that there is a possible common source and mechanism of transferring metals from the environment to the population.  相似文献   

Trans‐endoscopic diode laser fenestration of equine conchae via contralateral nostril approach          下载免费PDF全文

Filip Kološ MVDr  Štěpán Bodeček MVDr  PhD  Zdeněk Žert MVDr  CSc  Dipl ECVS 《Veterinary surgery : VS》2017,46(7):915-924

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Effect of weight fraction of total dry residue of cacao products on chocolate shelf life     

M. V. Osipov  N. B. Kondrat’ev  O. S. Rudenko  L. M. Aksenova 《Russian Agricultural Sciences》2010,36(5):382-383

The oxidative stability of fats extracted from various types of chocolate differing in content of total dry residue of cacao products during storage is investigated. Data allowing predicting the shelf life of chocolate are given. The induction time and shelf life of chocolate vary depending on the weight fraction of the total dry residue of cacao products.  相似文献   

Biochemical characteristics of hemp seeds from various regions of Russia     

S. V. Grigor’ev  T. V. Shelenga  V. S. Baturin  Yu. V. Sarana 《Russian Agricultural Sciences》2010,36(4):262-264

The composition and content of fatty acids in oil of ruderal hemp seeds collected in the Volga, Southern, Urals, Siberian, and Far Eastern federal districts are studied. The content of tetrahydrocannabinol is assessed.  相似文献   

Comparison of bacterial culture and real-time PCR for the detection of Salmonella in grow-finish pigs in Western Canada using a Bayesian approach     

Wilkins W  Waldner C  Rajić A  McFall M  Muckle A  Mainar-Jaime RC 《Zoonoses and public health》2010,57(Z1):115-120

The study objective was to evaluate the accuracy of a real-time polymerase chain reaction (RT-PCR) and a culture protocol used to detect Salmonella in the faeces of grow-finish pigs using a Bayesian approach. The RT-PCR was invA-gene-based assay, while the culture protocol included pre-enrichment in buffered peptone water, selective enrichment in tetrathionate and Rappaport-Vassiliadis broths, and isolation on semi-solid (modified semi-solid RV) or solid (XLT4, Rambach) agar plates. Bayesian analysis was performed using a two-test, two-population model with dependence between culture and RT-PCR and compared to a second model with conditional independence between these two tests. Two hundred and ninety three individual faecal and 294 pooled pen samples from grow-finish pig collected from 10 farms were tested and results were divided into two groups according to herd size (five herds <250 sows, five herds with >400 sows). In the dependence model, RT-PCR sensitivity (Se) and specificity (Sp) were estimated to be 90% (95% probability interval 74, 97) and 99% (98, 99), respectively. Culture Se was 92% (75, 99), while culture Sp was considered 100% as all culture-positive samples were confirmed by serotyping. In the conditional independence model, RT-PCR Se and Sp, and culture Se, were 96% (93, 98), 99% (98, 100) and 97% (94, 100), respectively. The dependence model resulted in posterior estimates of Se that were lower and with broader probability intervals than the independence model, indicating that when RT-PCR and culture are evaluated relative to each other, the correlation between these tests is an important source of bias and should be adjusted for during analysis. The RT-PCR evaluated in this study performed almost comparably to culture; given the cost savings associated with using this test and more timely results, the RT-PCR may be a useful alternative to culture for screening large numbers of samples, particularly when Salmonella prevalence is low.  相似文献   

Reduction of herbivore density as a tool for reduction of herbivore browsing on palatable tree species     

Jiří Kamler  Miloslav Homolka  Miroslava Barančeková  Jarmila Krojerová-Prokešová 《European Journal of Forest Research》2010,129(2):155-162

Browsing of overabundant free-living herbivores often limits the natural as well as artificial regeneration of forest in Central-European Mountains. The aim of the study was to assess the efficiency of the extensive reductions of herbivore populations for protection of forest regeneration in preferred areas. We analysed the relationship between the intensity of shoot browsing and relative density of herbivores in viewpoint of natural regeneration of secondary mountain spruce stands with low proportion of broadleaved trees in Králicky Sněžník Reserve (Czech Republic). The distribution of seasonally migrating herbivores was established by counting faecal pellet groups (standing crop method) in growing season. The intensity of browsing of spruce, beech and rowan was assessed using the proportion of browsed shoots on individual tree sapling. Density of red deer was re-counted from the number of pellet groups and it was 15–56 individual/km². The intensity of spruce browsing was low in the whole area in all seasons. In general, the intensity of rowan and beech shoot browsing was high in the whole area. There were no correlations between deer density and browsing intensity of rowan (browsing was severe in all plots). We conclude that the natural regeneration of attractive trees and shrubs is nearly impossible in habitats where proportion of these food items is too small, even when the density of herbivores is low. Reduction of herbivores density is useful for protecting spruce and other tree species with low preference by herbivores. Forest managers should take into account the high palatability of deciduous tree species and distribution of herbivores on localities. Preference of localities is often based on grasses in the food supply. Regeneration of highly palatable tree species requires both low density of herbivores and sufficient protection of saplings.  相似文献