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Chronic, excessive nitrogen deposition is potentially an important ecological threat to forests of the greater Sierra Nevada in California. We developed a model for ammonia bioindication, a major nitrogen pollutant in the region, using epiphytic macrolichens. We used non-metric multidimensional scaling to extract gradients in lichen community composition from surveys at 115 forested sites. A strong ammonia deposition gradient was detected, as evidenced by a high linear correlation with an index of ammonia indicator species conventionally known as “nitrophytes” (r = 0.93). This gradient, however, was confounded by elevation (r = ?0.54). We evaluated three statistical techniques for controlling the influence of elevation on nitrophytes: simple linear regression, nonlinear regression, and nonparametric regression. We used the unstandardized residuals from nonlinear regression to estimate relative ammonia deposition at each plot, primarily because this model had the best fit (r 2 = 0.33), desirable asymptotic properties, and it is easy to apply to new data. Other possible sources of noise in the nitrophyte-ammonia relationship, such as substrate pH and acidic deposition, are discussed. Lichen communities indicated relatively high deposition to forests of the southern Sierra Nevada, the Modoc Plateau, as well as in stands near urban areas. Evidence of elevated ammonia was also detected for popular recreation areas such as Sequoia and Yosemite National Parks. Lichen communities from forests in the Tahoe basin, northern Sierra Nevada, southern Cascades, and eastern Klamath Range appeared considerably less impacted. This model will be used for continual assessment of eutrophication risks to forest health in the region. 相似文献
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Branimir Jovančićević Miroslav Vrvić Jan Schwarzbauer Hermann Wehner Georg Scheeder Dragomir Vitorović 《Water, air, and soil pollution》2007,183(1-4):225-238
A review is given in this paper of the up-to-date results observed in differentiation and transformation studies on petroleum-type pollutants in underground and surface waters. Water and particulate matter derived from the locality of Pan?evo Petroleum Refinery, Serbia (River Danube alluvial formations). It was shown that distributions of n-alkanes, steranes and triterpanes, and δ13CPDB values of n-alkanes may successfully be used for qualitatively differentiating the petroleum-type pollutants from native organic matter in recent sedimentary formations. In underground waters, a petroleum-type pollutant is exposed to microbiological degradation which is manifested through relatively fast degradation of n-alkanes. Following an almost complete degradation of crude oil n-alkanes in underground water, the biosynthesis of novel, even carbon-number C16–C30 n-alkanes may be observed. It is shown that the n-alkane distribution observed in a petroleum-type pollutant may depend on the intensity of its previous interaction with water. The fate of petroleum-type pollutants in environmental waters may be predicted through laboratory simulative microbiological degradation experiments by using microorganism consortiums similar to those observed under relevant natural conditions, as well as on corresponding nutrient base. 相似文献
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Jovan Tucakov 《Plant foods for human nutrition (Dordrecht, Netherlands)》1958,5(1-2):108-120
Zusammenfassung Verfasser berichtet über die langjährigen Beobachtungen an den im Sandgebiet von Deliblato wachsenden Arznei-und Gewürz-pflanzen und über die mit einigen von ihnen angestellten Kulturversuche. 相似文献
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Ivana Imerovski Aleksandra Dimitrijevic Dragana Miladinovic Bosko Dedic Sinisa Jocic Branislav Kovacevic Dragana Obreht 《Plant Breeding》2013,132(1):115-120
Broomrape is a parasitic plant that significantly decreases yield of sunflower. Breeding for resistance has proved to be the most efficient method for suppressing broomrape infestation in the field; however, new races of parasite constantly emerge, and new resistance genes need to be discovered and introduced into cultivated sunflower lines. The aim of this work was to test SSR markers from linkage group 3 (LG3) to investigate whether they could be used for identification of a particular Or gene. Twenty sunflower inbred lines were used, and polymorphism between the lines with various resistance genes and genetic background was investigated. The used markers revealed DNA polymorphism between the investigated lines. Strong association of markers from LG3 with Or6, as well as Or4 and Or2 genes, was found. Identified markers could be used for introduction of these resistance genes into commercial sunflower lines and for establishment and identification of differential lines. 相似文献
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Branimir Jovančićević Mališa Antić Ivona Pavlović Miroslav Vrvić Vladimir Beškoski Alexander Kronimus Jan Schwarzbauer 《Water, air, and soil pollution》2008,190(1-4):299-307
This paper presents transformations of saturated hydrocarbons of petroleum type pollutants during ex situ bioremediation of soil on the pilot heap (halde), during a period of 6 months, within the grounds of Petroleum Refinery Pan?evo (Serbia). Samples for analysis were taken in time intervals of 2 weeks (P1–P12 samples). Organic substance was extracted by Soxhlet’s method and quantified. Isoprenoid aliphatics, in particular pristane and phytane, and polycyclic aliphatics of sterane and triterpane types in saturated hydrocarbon fractions were analysed by GC-MS (SIM method). Significant amounts of n-alkanes have not been detected. The MS-chromatogram revealed only marginal amounts of pristane and phytane in sample P1. Pristane and phytane occurred in sample P8, and in even higher quantities in the final sample P12. The proceeding bioremediation process was accompanied by the decrease of the relative amounts of pentacyclic terpanes of hopane type, compared to tri- and tetracyclic terpanes. In the initial sample P1 the distribution of steranes and hopanes follows a pattern, which is characteristic for crude oils. However, their identification by SIM method was not possible in samples P8 and P12 because of the reduced concentration. The observed changes in the alkane fractions’ compositions may be considered as atypical, referring to the fact that during oil biodegradation under natural conditions, decomposition of isoprenoids occurs much easier and faster than decomposition of polycyclic alkanes of tri-, tetra- and pentacyclic terpane, sterane and diasterane types, after the decomposition of n-alkanes has been almost completed. 相似文献
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Kovacevic Branislav Roncevic Savo Miladinovic Dragana Ivanisevic Petar Katanic Marina 《New Forests》2009,38(2):177-185
The relationship between early root and shoot formation at the beginning of the vegetation period and cutting survival on
sandy and loamy fluvisol for 14 genotypes of black poplars was analyzed. Considerable cutting mortality was observed only
within the first 80 days since planting. Intensive root formation in the first 20 days since the planting and vigorous shoot
growth and development in subsequent 20 days was observed in easy-to-root genotypes. Coefficients of correlation revealed
close relationship between early root and shoot growth and development and cutting survival of tested genotypes. The obtained
results could be used in the breeding process, as well as for the design of cultivar-adjusted nursery and plantation establishment
technology. Tested shoot characteristics, were found to be especially interesting since they could be measured rapidly, by
non-destructive means. 相似文献
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Katja N. Adamik DrMedVet ; Iwan A. Burgener DrMedVet DACVIM DECVIM ; Alan Kovacevic DrMedVet DECVIM ; Sebastian P. Schulze MRCVS Barbara Kohn DrMedVet DECVIM 《Journal of Veterinary Emergency and Critical Care》2009,19(3):247-253
Objective – To determine whether myoglobin (Mb) is a useful prognostic indicator for outcome and to investigate any relationship between Mb and mortality in dogs with gastric dilatation‐volvulus (GDV). Design – Prospective study. Setting – Veterinary teaching hospital. Animals – Seventy‐two dogs with GDV. Interventions – Blood sampling. Measurements and Main Results – Mb levels were measured at the time of diagnosis (Mbt0), 24 hours (Mbt1), and 48 hours (Mbt2) after signs of GDV were recognized. Fifty‐seven dogs survived (group I) and 15 dogs did not survive (group II). Mb t0 differed significantly between groups (P=0.04). Mbt0 in group I ranged from <30 to >700 ng/mL (n=57, median 74 ng/mL), and in group II from 34 to >700 ng/mL (n=15, median 238 ng/mL). Analysis of a receiver operating characteristic curve of Mbt0 suggested that the best single cutpoint would be 168 ng/mL (sensitivity 60.0%, specificity 84.2%). Fifty percent of dogs with Mbt0>168 ng/mL were euthanized, while 88.9% with Mbt0<168 ng/mL survived. Mbt1 and Mbt2 differed significantly between groups I and II. Mbt1 in group I ranged from 32 to >700 ng/mL (n=55, median 123 ng/mL), and Mbt1 in group II ranged from 131 to 643 ng/mL (n=7, median 343 ng/mL) (P=0.006). Mbt2 in group I ranged from 30 to 597 ng/mL (n=54, median 101 ng/mL), and in group II from 141 to >700 ng/mL (n=8, median 203 ng/mL) (P=0.02). Conclusions – In this study, Mbt0 is a moderately sensitive and specific prognostic indicator. Almost 90% of the dogs below the cutpoint survived to discharge, whereas 50% with Mbt0 above the cutpoint did not survive. 相似文献