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141.
Theory predicts that the probability that an ecosystem will provide a consistent level of functioning over a given unit of time, i.e. the reliability of ecosystem processes, should increase with species richness. There is growing evidence that plant diversity increases the temporal stability of productivity, but only a few studies have investigated its impact on the reliability of ecosystem processes, and information on whether this propagates to the belowground system is virtually lacking. Using a microcosm experiment with plant communities varying in species and functional group diversity and two decomposer groups (earthworms and Collembola) we investigated the effects of plant diversity on the reliability of the belowground system and vice versa, the effect of decomposers on the reliability of plant productivity. Generally, plant diversity increased the reliability of above- and belowground processes by significantly increasing the reliability of eight out of eleven measured ecosystem parameters (six out of nine belowground responses). Plant functional group diversity had a stronger stabilising effect than species richness on above- and belowground processes including plant shoot and total biomass, microbial basal respiration and Collembola densities. By contrast, in the presence of both decomposer groups the reliability of decomposer populations was reduced. The results indicate that plant diversity effects propagate into the belowground system and increase the reliability of belowground processes via more consistent plant derived belowground inputs. 相似文献
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143.
Vicentini CB Romagnoli C Andreotti E Mares D 《Journal of agricultural and food chemistry》2007,55(25):10331-10338
The present study was carried out to investigate the antifungal activity of pyrazole/isoxazole-3-carboxamido-4-carboxylic acids, 4-oxo-5-substituted pyrazolo[3,4-d]pyrimidine-6-thiones, and N-alkyl/aryl-N'-(4-carbethoxy-3-pyrazolyl)thioureas against Pythium ultimum, Botrytis cinerea, and Magnaporthe grisea. The results on growth inhibition showed differences in the sensitivity of the three fungi to the tested substances, and in general P. ultimum was shown to be the most sensitive. On all phytopathogens the best results within the pyrazole/isoxazolecarboxamide series are given by the compounds with the carboxamide and carboxylic groups in positions 3 and 4; the presence of these groups seems to be critical for biological activity in this series of compounds. Among the pyrazolopyrimidines the derivative supplied with the benzylic group was the most active on the three fungi and in particular against P. ultimum. Several compounds belonging to the thiourea series are able to inhibit selectively M. grisea at 50 and 10 microg mL(-1), doses at which the reference commercial compound tricyclazole had low or no effect. 相似文献
144.
The dagger nematode Xiphinema index has a high economic impact in vineyards by direct pathogenicity and above all by transmitting the Grapevine fanleaf virus (GFLV). Agrochemicals have been largely employed to restrict the spread of GFLV by reducing X. index populations but are now banned. As an alternative to nematicides, the use of fallow plants between two successive vine crops was assessed. We selected plant species adapted to vineyard soils and exhibiting negative impact on nematodes and we evaluated their antagonistic effect on X. index in greenhouse using artificially infested soil, and in naturally infested vineyard conditions. The screening was conducted with plants belonging to the families Asteraceae (sunflower, marigold, zinnia, and nyjer), Poaceae (sorghum and rye), Fabaceae (white lupin, white melilot, hairy vetch, and alfalfa), Brassicaceae (rapeseed and camelina), and Boraginaceae (phacelia). In the greenhouse controlled assay, white lupin, nyjer, and marigold significantly reduced X. index populations compared with that of bare soil. The vineyard assay, designed to take into account the aggregative pattern of X. index distribution, revealed that marigold and hairy vetch are good candidates as cover crops to reduce X. index populations in vineyard. Moreover, this original experimental design could be applied to manage other soilborne pathogens. 相似文献
145.
Dewhirst SY Birkett MA Loza-Reyes E Martin JL Pye BJ Smart LE Hardie J Pickett JA 《Pest management science》2012,68(10):1419-1429
BACKGROUND: Two important pests of the sweet pepper, Capsicum annuum, are the peach potato aphid, Myzus persicae, and the glasshouse potato aphid, Aulacorthum solani. Current aphid control measures include the use of biological control agents, i.e. parasitic wasps, but with varying levels of success. One option to increase parasitoid efficiency is to activate plant defence. Therefore, sweet pepper plants were treated with the naturally occurring plant defence activator cis-jasmone, and its impact upon the behaviour and development of aphids and aphid parasitoids was investigated. RESULTS: Growth rate studies revealed that the intrinsic rate of population increase of A. solani and M. persicae on sweet pepper plants treated with cis-jasmone (cJSP) was not affected compared with untreated plants (UnSP), but the positive behavioural response of alate M. persicae towards the volatile organic compounds (VOCs) from UnSP was eliminated by cis-jasmone treatment 48 h previously (cJSP48). In addition, the aphid parasitoid Aphidius ervi preferred VOCs from cJSP48 compared with UnSP, and a significant increase in foraging time was also observed on cJSP. Analysis of VOCs collected from cJSP48 revealed differences compared with UnSP. CONCLUSION: There is evidence that treatment with cis-jasmone has the potential to improve protection of sweet pepper against insect pests. © Crown copyright 2012. Reproduced with permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd. 相似文献
146.
Scazzola Roberto Matteucci Gabriele Guerzoni Stefano Chiamenti Elisa Rossini Paolo Molinaroli Emanuela 《Water, air, and soil pollution》2004,153(1-4):195-203
Trace metal (As, Cd, Cr, Ni, Hg, Pb) concentrations in soil samples collected around the Porto Marghera (Italy) industrial zone (2–40 km) near the city of Venice were compared with direct measurements of atmospheric deposition measured at comparable distances from the same source. Concentrations of Cd and Pb in soils decreased exponentially with increasing distance from the source; less clear signals were detected for As, Cr and Ni. Significant differences were found among the soils, which were partially resolved when their clay contents were normalised. Preliminary comparisons of fluxes of Cd and Pb derived from soil with direct deposition measurements showed increasing values with longer integration times. Annual Cd and Pb flux values of one year of direct deposition were 5 to 10 times lower than mean annual fluxes derived from soils,integrating 50 to 100 years. Values range from ~0.1–0.4 to 1–2 mg m-2 yr-1 for Cd, and from 3–18 to 50–100 mg m-2 yr-1 for Pb. These results fit information on `historical' emission trends as recorded in sediments of the lagoon. 相似文献
147.
148.
Critical care veterinarians observe a wide variety of patients who easily become malnourished and display negative nitrogen balance due to inappetance, complete anorexia, vomiting, or inability to normally prehend food, as in patients with head and facial trauma (Tables 1 and 2). Negative nitrogen balance is associated with delayed wound healing and increased incidences of gastroinstestinal mucosal atrophy, bacterial translocation, sepsis, and mortality. Early interventional nutrition is necessary for maintenance of normal function and for proper healing to occur. While total parenteral nutrition (TNP) is an option, enteral nutrition is preferred whenever possible. Enterocytes undergo atrophy within several days in the absence of direct trophic stimuli Within the intestinal lumen.
"If the gut works, use it" has gained widespread Popularity in early interventional nutrition in the critically ill veterinary patient. Force-Feeding is often stressful for both patient and caretaker alike. Instead, tube feeding is often well tolerated and an easier route for enteral nutrition. The following methods of tube feeding have been described: nasoesophageal, nasogastic, nasojejunostomy, esophagostomy, pharyngostomy, gastrostomy, and jejunostomy.
Esophagostomy tubes were first described for use in human patients with maxillofacial and cervical neoplasta. Later, Dr. Crowe described their use for veterinary patients (1989). Since that time, several methods for esophagostomy tube placement have been proposed. The modified percutaneous method is one of the easiest to perform, and requires minimal equipement. 相似文献
"If the gut works, use it" has gained widespread Popularity in early interventional nutrition in the critically ill veterinary patient. Force-Feeding is often stressful for both patient and caretaker alike. Instead, tube feeding is often well tolerated and an easier route for enteral nutrition. The following methods of tube feeding have been described: nasoesophageal, nasogastic, nasojejunostomy, esophagostomy, pharyngostomy, gastrostomy, and jejunostomy.
Esophagostomy tubes were first described for use in human patients with maxillofacial and cervical neoplasta. Later, Dr. Crowe described their use for veterinary patients (1989). Since that time, several methods for esophagostomy tube placement have been proposed. The modified percutaneous method is one of the easiest to perform, and requires minimal equipement. 相似文献
149.
Nagai S Dubrana K Tsai-Pflugfelder M Davidson MB Roberts TM Brown GW Varela E Hediger F Gasser SM Krogan NJ 《Science (New York, N.Y.)》2008,322(5901):597-602
Recent findings suggest important roles for nuclear organization in gene expression. In contrast, little is known about how nuclear organization contributes to genome stability. Epistasis analysis (E-MAP) using DNA repair factors in yeast indicated a functional relationship between a nuclear pore subcomplex and Slx5/Slx8, a small ubiquitin-like modifier (SUMO)-dependent ubiquitin ligase, which we show physically interact. Real-time imaging and chromatin immunoprecipitation confirmed stable recruitment of damaged DNA to nuclear pores. Relocation required the Nup84 complex and Mec1/Tel1 kinases. Spontaneous gene conversion can be enhanced in a Slx8- and Nup84-dependent manner by tethering donor sites at the nuclear periphery. This suggests that strand breaks are shunted to nuclear pores for a repair pathway controlled by a conserved SUMO-dependent E3 ligase. 相似文献
150.
Elena Badillo Elisa Escudero Verónica Hernandis Juan Sebastián Galecio Pedro Marín 《Journal of veterinary pharmacology and therapeutics》2020,43(1):50-56
The single-dose disposition kinetics of cefonicid were determined in clinically normal lactating goats (n = 6) after intravenous (IV), intramuscular (IM) and subcutaneous (SC) administration of a conventional formulation, and after subcutaneous administration of a long-acting formulation (SC-LA). Cefonicid concentrations were determined by high performance liquid chromatography with ultraviolet detection. The concentration–time data were analysed by noncompartmental pharmacokinetic methods. Steady-state volume of distribution (Vss) and clearance (Cl) of cefonicid after IV administration were 0.14 ± 0.03 L/kg and 0.51 ± 0.07 L/h·kg, respectively. Following IM, SC and SC-LA administration, cefonicid achieved maximum plasma concentrations of 14.46 ± 0.82, 11.98 ± 1.92 and 17.17 ± 2.45 mg/L at 0.26 ± 0.13, 0.42 ± 0.13 and 0.83 ± 0.20 hr, respectively. The absolute bioavailabilities after IM, SC and SC-LA routes were 75.34 ± 11.28%, 71.03 ± 19.14% and 102.84 ± 15.155%, respectively. After cefonicid analysis from milk samples, no concentrations were found above LOQ at any sampling time. From these data, cefonicid administered at 20 mg/kg each 12 hr after SC-LA could be effective to treat bacterial infections in lactating animals not affected by mastitis problems. 相似文献