Instantaneous and potential radiation effect on underplanted European beech below Norway spruce canopy     

Matjaž Čater  I. Schmid  M. Kazda 《European Journal of Forest Research》2013,132(1):23-32

In even-aged, 120-year-old Norway spruce stands with underplanted beech (in 1995) four permanent research plots were established, each 100 × 100 m in size. Twelve subplots were selected on each plot along a light gradient from complete canopy closure to open light conditions. On each plot, photon flux density (PFD) was measured continuously, and during same time interval (August 2008, 2009), color digital hemispherical photographs were taken. Cumulative PFD values for measuring points were compared with potential PFD radiation obtained from hemispherical photograph analysis for different angle of hemisphere and different parameters from hemispherical image analysis (gap fraction, total openness and direct, indirect and total amount of radiation). Cumulative and average daily values for the plots were compared; 120° hemispherical photograph angle, gap fraction and total openness were the variables that explained the largest proportion of variance in light transmittance. Determination coefficients between direct and total light component were highest for the total potential radiation and lowest for the diffuse light component. Comparison between potential and instantaneous light measurements for radial, height increment and SLA of young beech showed that instantaneous radiation measurements explained height increment best; 120° of hemisphere proved to be the best explaining angle.  相似文献   

Das Vorkommen von Mehltaupilz auf der Wiesen-Platterbse (Lathyrus pratensis L.)     

Bohumila Voženílková  Milan Kobes  František Klimeš  Bohuslav Čermák  Vlasta Ptáčníková 《Gesunde Pflanzen》2007,59(4):179-182

The aim of small-site experiments carried out in the area of the foothills of the ?umava Mts. was to determine the etiological agent of the disease of meadow peavine (Lathyrus pratensis L.). The experimental locality (Kaplice-Chuchelec) was situated in an altitude of 655?m a.s.l. The investigation was accomplished in the years 2004–2005. During the vegetation period we observed whitish to grey-white soft cover of mycelium on the leaves of meadow peavine. These characteristic symptoms of powdery mildew (Erysiphe trifolii Grev.) were found on the plants in the observed area at the end of summer and in autumn. In the area of interest with permanent grassland we evaluated the following variants: first M – mulched stands (mulched once), second L – fallow stands, third K – mown stands (mowing once to three times), and fourth P – pasture stands (grazed by cattle twice to four times). The observed stands were managed in different ways from 2000, and in relation to the ways and intensity of management we observed the changes and coverage of creeping legumes including Lathyrus pratensis. Phytopathological analysis of plants with the symptoms of Erysiphe fungi attack was accomplished in all variants and repetitions during the whole vegetation period. The observation of particular variants was carried out in four repetitions, the size of the sites being 30?m² (4?×?30?m²), and we evaluated the total number of Lathyrus pratensis plants as well as the number of the plants attacked by powdery mildew. Powdery mildew occurrence on Lathyrus pratensis at different management methods of grass stands was statistically processed (in STATISTICA program). The three-year investigation of Lathyrus pratensis L. yielded statistical evidence that the most significant growth of fungal disease Erysiphe trifolii Grev. was recorded in fallow stands. On the other hand, the least occurrence of the disease was found in the pasture stands, which were grazed by the cattle.  相似文献   

Effect of low‐dose N application and early mowing on plant species composition of mesophilous meadow grassland (Arrhenatherion) in Central Europe     

K. Čámská  H. Skálová 《Grass and Forage Science》2012,67(3):403-410

Semi‐natural temperate grasslands in Europe make an important contribution to biodiversity, but their existence has been endangered by both agricultural intensification and abandonment. In the Czech Republic, Arrhenatherion meadows are a typical example, with their conservation made difficult by the scarcity of research on effective management practices. We examined effects of two potentially useful approaches, application of 56 kg N ha^?1 and earlier first mowing (i.e. in the middle of May, about 2 weeks earlier than usual), on species composition of an Arrhenatherion grassland in central Bohemia over a 7‐year period (1998–2004). These treatments did not influence species richness, but resulted in small changes in canopy structure in terms of cover of individual species and particular plant functional groups. N application resulted in increases in nitrophilous species and tall graminoids, especially Alopecurus pratensis, Festuca pratensis, Heracleum sphondylium and Ranunculus acris, and in decreases in short graminoids. Earlier mowing decreased tall herbs, especially H. sphondylium, and might thus be useful in compensating for increases in some nitrophilous species owing to N application. However, earlier mowing had negative impacts on spring‐flowering species in terms of reduced cover.  相似文献   

Production,size, and germination of broad‐leaved dock seeds collected from mother plants grown under different nitrogen,phosphorus, and potassium supplies     

JANA HRDLIČKOVÁ  MICHAL HEJCMAN  VERONIKA KŘIŠŤÁLOVÁ  VILÉM PAVLŮ 《Weed Biology and Management》2011,11(4):190-201

Rumex obtusifolius is believed to be a nitrophilous weedy species that spreads mainly by seed. However, the effects of nutrient availability on seed production never have been investigated. In this study, how the amount of seed production per plant, the chemical composition of the seeds, and their size and germination are affected by the supply of N, P, and K was investigated. A pot fertilizer experiment with 10 treatments (combinations of 0, 150 [N1], and 300 [N2] kg N ha^?1, 0, 40 [P1], and 80 [P2] kg P ha^?1, and 0 and 100 [K] kg K ha^?1 applied twice per vegetation season) was carried out in Prague, Czech Republic, in 2008 and 2009. The seeds from plants that were cultivated since the spring were collected each August. The germination of the seeds was determined in long‐daylight conditions at a stable temperature of 20°C. The number of seeds per plant ranged from 0 in the P1 and P2 treatments and <200 in the control and K treatments to almost 9000 in the N2P2K treatment. The number of seeds per plant was positively correlated with the number of stems per plant and the number of seeds per stem. The relationship between the amount of seeds per plant and the individual seed weight was positive. The concentration of N, P, and K in the seeds was affected by the treatments. The weight of 1000 seeds ranged from 1.3 to 1.7 g. The seed length ranged from 2.11 to 2.34 mm and the seed width varied from 1.26 to 1.42 mm. With the exception of the control (with 94% germination), the amount of seed germination was >98% in all the other treatments in 2008. In 2009, the amount of seed germination was >95% in all the treatments, except N1 and N2, where 93% and 89% germination, respectively, was recorded. The germination rate was positively related to the P concentration in the seeds. The amount of time that was necessary for 50% seed germination ranged from 1.53 to 2.89 days and was not related to the N concentration in the seeds, but it was negatively related to the P and K concentrations. A balanced N, P, and K supply to the mother plant strongly affected the number of produced seeds and their chemical composition and germination ability.  相似文献   

Predicting ash dieback severity and environmental suitability for the disease in forest stands     

Eva Chumanová  Dušan Romportl  Ludmila Havrdová  Daniel Zahradník  Vítězslava Pešková  Karel Černý 《Scandinavian Journal of Forest Research》2019,34(4):254-266

Ash dieback, caused by the ascomycete fungus Hymenoscyphus fraxineus, has been rapidly expanding across Europe during the last two decades, posing a considerable threat to native ash populations. In this study, we applied regression-based models trained by field data, in conjunction with geographic information systems, to produce spatial predictions of ash dieback severity and environmental suitability for the disease in Czech forests. A model of actual ash dieback severity relates disease extent to silvicultural and environmental characteristics of forest stands and their neighbourhood, while a model of environmental suitability for the disease quantifies the relative susceptibility of sites to the disease, independent of the current silvicultural characteristics. The final predictive maps suggested that fertile lowlands and humid areas bordering Poland and Slovakia were the most endangered regions. Areas at the lowest risk of damage were concentrated in dry areas and in highland and mountain areas in the western part of the country, usually with poor soils on acid bedrock. Predictions of actual disease severity are an effective tool for guiding the current management of infested stands whereas predicting environmental suitability is useful for making long-term strategic decisions, e.g. identifying areas where future ash regeneration and cultivation may be unsuccessful.  相似文献   

Influence of cutting regime and fertilizer application on the botanical composition,yield and nutritive value of herbage of wet grasslands in Central Europe     

J. Čop  M. Vidrih  J. Hacin 《Grass and Forage Science》2009,64(4):454-465

The changes in dry matter (DM) yield, botanical composition and nutritive value of herbage to ruminants of two wet grasslands, Arrhenatherum elatius grassland (Experiment 1) and a Molinia caerulea fen meadow (Experiment 2), in which a range of cutting and fertilizer treatments were imposed in 1999, were assessed after 4–7 years of treatment imposition. Both experiments had a split‐plot design with four replicates. In Experiment 1 the three main‐plot cutting treatments were two cuts with a delayed first cut, three cuts and four cuts during the growing season of each year. In Experiment 2 the cutting treatments were two cuts with a traditional harvest time, two cuts with a delayed first cut and three cuts. The four sub‐plot fertilizer treatments were an unfertilized control, application of a phosphorus and potassium (PK) fertilizer, application of a nitrogen (N) and PK fertilizer to the first cut only (N₁PK) and application of PK plus N applied to each of two, three or four cuts (N_c PK). Application of fertilizer influenced yield and botanical composition of herbage more than the cutting treatments while the opposite occurred for nutritive value of the herbage. Application of fertilizer increased the proportion of tall grasses in Experiment 1 and forbs in Experiment 2. The proportion of Equisetum palustre, present only in Experiment 1, was reduced from 0·33 to less than 0·01 by increased cutting frequency together with the NPK fertilizer treatments. In Experiment 1 diversity of vascular plants was negatively affected only by the four‐cuts treatment while on both wet grasslands other cutting and fertilizer application treatments had no effect. Changes in DM yield of herbage caused by the cutting and fertilizer application treatments were similar for both vegetation types with DM yield increased significantly by fertilizer application but only slightly or not reduced by increasing the cutting frequency. Nutritive value of herbage was positively correlated with cutting frequency and was most influenced at the first cut.  相似文献   

Characterizing the potential habitat of European anchovy Engraulis encrasicolus in the Mediterranean Sea,at different life stages     

M. GIANNOULAKI  M. IGLESIAS  M. P. TUGORES  A. BONANNO  B. PATTI  A. DE FELICE  I. LEONORI  J. L. BIGOT  V. TIČINA  M. M. PYROUNAKI  K. TSAGARAKIS  A. MACHIAS  S. SOMARAKIS  E. SCHISMENOU  E. QUINCI  G. BASILONE  A. CUTTITTA  F. CAMPANELLA  J. MIQUEL  D. OÑATE  D. ROOS  V. VALAVANIS 《Fisheries Oceanography》2013,22(2):69-89

Identification of the potential habitat of European anchovy (Engraulis encrasicolus) at different life stages in relation to environmental conditions is an interesting subject from both ecological and management points of view. For this purpose, acoustic data from different seasons and different parts of the Mediterranean Sea along with satellite environmental and bathymetry data were modelled using generalized additive models. Similarly, egg distribution data from summer ichthyoplankton surveys were used to model potential spawning habitat. Selected models were used to produce maps presenting the probability of anchovy presence (adults, juveniles and eggs) in the entire Mediterranean basin, as a measure of habitat adequacy. Bottom depth and sea surface chlorophyll concentration were the variables found important in all models. Potential anchovy habitats were located over the continental shelf for all life stages examined. An expansion of the potential habitat from the peak spawning (early summer) to the late spawning season (early autumn) was observed. However, the most suitable areas for the presence of anchovy spawners seem to maintain the same size between seasons. Potential juvenile habitats were associated with highly productive inshore waters, being less extended and closer to coast during winter than late autumn. Potential spawning habitat in June and July based on ichthyoplankton surveys overlapped but were wider in extent compared with adult potential habitat from acoustics in the same season. Similarities and dissimilarities between the anchovy habitats as well as comparisons with sardine habitats in the oligotrophic Mediterranean Sea and other ecosystems with higher productivity are discussed.  相似文献   

Quality and Antioxidant Activity of Buckwheat-Based Cookies Designed for a Raw Food Vegan Diet as Affected by Moderate Drying Temperature     

Iveta Brožková  Veronika Dvořáková  Kateřina Michálková  Libor Červenka  Helena Velichová 《Plant foods for human nutrition (Dordrecht, Netherlands)》2016,71(4):429-435

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Effect of Allium flavum L. and Allium melanantherum Panč. Extracts on Oxidative DNA Damage and Antioxidative Enzymes Superoxide Dismutase and Catalase     

Dragana Mitić-Ćulafić  Biljana Nikolić  Nataša Simin  Nebojša Jasnić  Dragana Četojević-Simin  Maja Krstić  Jelena Knežević-Vukčević 《Plant foods for human nutrition (Dordrecht, Netherlands)》2016,71(1):28-34

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Electrophysiological and behavioural responses of <Emphasis Type="Italic">Ips typographus</Emphasis> (L.) to trans-4-thujanol—a host tree volatile compound     

Laima Blažytė-Čereškienė  Violeta Apšegaitė  Sandra Radžiutė  Raimondas Mozūraitis  Vincas Būda  Dalė Pečiulytė 《Annals of Forest Science》2016,73(2):247-256

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