The physicochemical and microbiological status of a restored bog in Québec: Identification of relevant criteria to monitor success     

Roxane Andersen  André-Jean Francez 《Soil biology & biochemistry》2006,38(6):1375-1387

The Bois-des-Bel Sphagnum peatland (Rivière du Loup, QC) was restored in 1999 after 20 years of abandonment. Restoration work included not only the blockage of drainage ditches, but also the reintroduction of plant material including Sphagnum remains. Following restoration, the physicochemical and microbial characteristics (biomass, activity and composition) of the peat were analysed. The goal was to investigate the functional status of the restored ecosystem. The high N:P (>20) and N:K (>15) ratios indicated possible K and P deficiencies in the restored and the cutover sites, which is mainly associated with the intense leaching and the high degree of decomposition of the peat in these sites. The concentrations of , P and K in the top layer of the restored site were closer to those of the natural site, which indicated a possible effect of restoration on the physicochemistry of the restored site. Microbial biomass values derived from the FE technique followed a gradient natural>restored>cutover through the profile, which was not the case with the SIR technique. Values from SIR varied overall between 0.19 and 4.88 mg C g⁻¹ and were significantly higher in the natural site. The natural peatland site had significantly (P<0.05) greater cumulative C-CO₂ production (surface aerobic: 4.5-8.7 μg C-CO₂ g⁻¹ h⁻¹). The poor organic matter quality was the main explanation for the low respiration rates of the surface layer in the restored and the cutover site. All CO₂ respiration data were plotted against time and the resulting curves were successfully fitted to a global kinetic model. Methane production was detected at low but measurable rates in the natural and the restored samples, but not in the cutover peat. Overall, the results confirmed the existence of a lag between the positive response of vegetation to restoration and that of the microbial compartment. This study also pointed out that some physicochemical dysfunctions remained even after three growing seasons following restoration in the subsurface horizons studied.  相似文献   

Effect of ultrasonic cavitation on small and large organisms for water disinfection during fish transport          下载免费PDF全文

Eirik Svendsen  Stine W Dahle  Andreas Hagemann  Jens Birkevold  Stephanie Delacroix  Aage Bjørn Andersen 《Aquaculture Research》2018,49(3):1166-1175

Motivated by the need for additional tools to disinfect discharge water from well boats, and to prevent distribution of salmon lice, the effect of ultrasonic cavitation on the planktonic stages of the salmon louse, nauplii and copepodids, as well as marine heterotrophic bacteria, and the marine green microalgae Tetraselmis suecica, has been investigated. Survival and morphology were registered after different exposure times. Efficacy of the ultrasonic cavitation treatments varied with exposure time. A reduction in survival was registered even for the shortest exposure time (5 seconds) for both naupliar and copepodid stages of the salmon louse (36.7 ± 11.5 and 67.20 ± 7.2% survival respectively). Survival reached zero after exposure times of 20 and 60 seconds for the nauplii and copepodid stages, respectively. A reduction in 70% was observed for bacteria at all exposure times (5 to 300 s), while a reduction of 95% was observed after 300 s for algal cells. The logged energy transfer to the samples was on average 17.5 J/s. In conclusion, cavitation treatment is destructive for the planktonic stages of salmon lice, and may contribute to reduce discharge of pathogens and parasites from well boats when adapted for this purpose and combined with existing water disinfection methods.  相似文献   

Assessment of the inheritance of resistance and tolerance in cherry (Prunus sp.) to Blumeriella jaapii,the causal agent of cherry leaf spot          下载免费PDF全文

K. L. Andersen  A. M. Sebolt  G. W. Sundin  A. F. Iezzoni 《Plant pathology》2018,67(3):682-691

Cherry leaf spot (CLS), caused by Blumeriella jaapii, is a serious fungal disease of sour cherry (Prunus cerasus). Cultivar Montmorency, the major cultivar grown in the United States, is highly susceptible to CLS. As many as 10 fungicide sprays can be required each growing season to combat this disease; therefore, developing CLS‐resistant cultivars is a top breeding priority. Germplasm previously reported to be resistant or tolerant to CLS was acquired and incorporated into the sour cherry breeding programme at Michigan State University (MSU) and included three cherry species: sour cherry, sweet cherry (P. avium), and the wild species P. canescens. This study aimed to: (i) compare the CLS disease progression profile of the susceptible cultivar Montmorency with those of the resistant and tolerant germplasm; and (ii) gain an understanding of the inheritance of these resistance and tolerance traits by evaluating the host response of progeny individuals belonging to families derived from this germplasm. Significant differences were observed between the susceptible Montmorency and the tolerant and resistant accessions in their response to CLS and its progression during the growing season. Evaluation of the CLS host responses of progeny individuals derived from this germplasm supported a dominant two‐gene model for P. canescens‐derived resistance and a recessive gene model for sweet cherry‐derived tolerance. These insights into disease progression and trait inheritance improve the efficiency and potential success of breeding sour cherry cultivars with durable resistance to CLS.  相似文献   

Episodic Release of Arsenic,Copper and Chromium from a Wood Preservation Site Monitored by Transplanted Aquatic Moss     

Rasmussen  Grete  Andersen  Sjur 《Water, air, and soil pollution》1999,109(1-4):41-52

Leaching from a wood preservation site in Norway, severely contaminated with copper (Cu), chromium (Cr) and arsenic (As), was investigated using aquatic moss. The objectives were three-fold: (i) study the release of trace metals into a river during a rainfall episode, (ii) determine whether aquatic moss can be used to detect leaching during episodic events when sampling is frequent, and (iii) determine whether aquatic moss can be used as a bioindicator in brackish water. Aquatic moss (Fontinalis antipyretica was transplanted into the river in eight moss-cages. Samples were collected during one episode of rainfall. Concentrations of As in the moss increased during the rainfall event. Cu and Cr concentrations in the moss increased during the beginning of the period, but tended to decrease because of dilution towards the end. Accumulation patterns of Cu, Cr and As in the moss varied probably because of differences in binding affinity to soil and to the moss. The use of F. antipyretica proved that leaching of trace metals do increase during a rainfall event. It was shown that aquatic moss can be used as an indicator to monitor leaching during rainfall events, however, timing of sampling is critical. Although the moss survived in brackish water, it is questioned whether ions in the water can cause competition and desorption of the metals in the moss.  相似文献   

Haemodynamic effects of ATP in dogs during hypoxia-induced pulmonary hypertension     

B. Driessen  S.C. Haskins  P.J. Pascoe  L.D. Tripp  & J.A. Reitan 《Journal of veterinary pharmacology and therapeutics》1999,22(3):213-219

Pulmonary hypertension may result from an increase in vascular resistance caused by persistent hypoxia. We have investigated the effects of adenosine triphosphate (ATP), administered into the pulmonary artery, on haemodynamic changes occurring in anaesthetized adult dogs subjected to acute hypoxic pulmonary vasoconstriction. Hypoxia alone (ventilation with 10% O2/90% N2) caused significant increases in mean pulmonary arterial blood pressure (PAP), central venous pressure (CVP), and cardiac index (CI) by 71, 102 and 38%, respectively. ATP (0.03-3.0 micromol/kg/min approximately 0.02-1.65 mg/kg/min), when infused under hypoxic conditions, significantly reduced both mean PAP and systemic arterial blood pressure (ABP) in a dose-dependent manner. The maximum decrease in mean PAP amounted to 20%; mean ABP, on the other hand, was decreased by up to 52% (P<0.01). Heart rate, CI, CVP and pulmonary occlusion pressure were not dose-dependently affected by ATP. Our data indicate that while pulmonary arterial administration of ATP in mature dogs during hypoxic pulmonary hypertension causes dilation in the pulmonary vascular bed, it is even more effective in dilating the systemic vasculature. This result suggests a need for further evaluation and warrants cautious use of ATP in the treatment of hypoxic pulmonary hypertension in adult dogs.  相似文献   

Nutrient uptake and growth of potato: Arbuscular mycorrhiza symbiosis interacts with quality and quantity of amended biochars     

Qi Yang  Sabine Ravnskov  Mathias Neumann Andersen 《植物养料与土壤学杂志》2020,183(2):220-232

Aims : The aim of this study was to explore interactive effects between quality (types) and quantity (application rates) of biochar as well as of arbuscular mycorrhiza (AM) symbiosis on the growth of potato plants. Methods : A low P sandy loam soil was amended with 0%, 1.5%, or 2.5% (w/w) of either of 4 types of biochar, which were produced from wheat straw pellets (WSP) or miscanthus straw pellets (MSP) pyrolyzed at temperatures of either 550°C or 700°C. Potato plants grown in pots containing the soils or soil biochar mixture were inoculated with or without AM fungus (AMF), Rhizophagus irregularis. The experiment was carried out under fully irrigated semi‐field conditions and plants were harvested 101 days after planting. Results : Application of high temperature biochar decreased growth, biomass and tuber yield of potato plants, while the low temperature biochar had a similar effect on yield as plants grown without biochar amendment. Total biomass of potato plants were decreased with the increasing rate of biochar. Arbuscular mycorrhizal fungus inoculation stimulated the growth of potato plants in all organs, increased tuber biomass significantly in 1.5% MSP700 amended plants, and to a lesser degree for WSP700, MSP550, and WSP550. In addition, plant biomass gain was linearly related to N, P, and K uptake, the ratio of P to N in the leaf of plants indicated that all treatments were mainly P‐limited. A multiple linear regression using P uptake and biochar rate as independent variables explained 91% of the variation in total biomass. The single effect of AMF inoculation, type and rate of biochar affected plant N, P and K uptake similarly. While AMF inoculation significantly increased P uptake in potato plants grown in soil with WSP700 or MSP700 despite of the rate of biochar. In general, application of biochar significantly increased AMF root colonization of potato plants. Conclusions : The application of MSP550 at 1.5% combined with AMF stimulated growth of potato the most. Furthermore, the results indicated that the interactive effect of AMF inoculation, biochar type and application rate on potato growth to a large extent could be explained by effects on plant nutrient uptake.  相似文献   

Development and mapping of gene-tagged SNP markers in laccases of maize (Zea mays L.)     

J. R. Andersen    T. Asp    Y. C. Lu    M. Kloiber-Maitz  M. Ouzonova    T. Luebberstedt 《Plant Breeding》2009,128(4):423-425

Laccases, EC 1.10.3.2 or p -diphenol : dioxygen oxidoreductases, have been proposed to be involved in the oxidative polymerization of monolignols into lignins in plants. While 17 laccases have been identified in Arabidopsis , only five ( ZmLac1–5 ) have so far been identified in maize. By a bioinformatic approach, 14 putative laccases were identified in maize. One putative laccase was identical to ZmLac1 , while five were highly homologous to either ZmLac4 or ZmLac5 . Sequence alignment of allelic sequences enabled the development of TaqMan single nucleotide polymorphism (SNP) markers for nine putative laccases. Four of these gene-tagged SNP markers were validated in a doubled-haploid mapping population of 140 individuals, mapping these loci to chromosomes 1, 2, 3 and 7, respectively.  相似文献   

属间体细胞杂交创建甘蓝型油菜细胞质雄性不育系及其鉴定   总被引：26，自引：2，他引：26  

胡琼  李云昌  梅德圣  方小平  Lise N.Hansen  Sven B.Andorsen 《中国农业科学》2004,37(3):333-333

 利用原生质体融合技,获得了甘蓝型油菜品种中双4号与新疆野生油菜野油18的对称性体细胞杂种。杂种当代建成的6株植株中有2株雄性不育株。用中双4号做轮回亲本与不育株回交,不育株率随回交代数增加而升高,至BC3代大部分株系的不育株率接近100%,到BC4代不育性稳定,群体中无育性分离现象。用波里马CMS的恢复系和保持系与其测交,6个甘蓝型油菜品系均可保持该不育系的不育性,表明该雄性不育胞质与Pol不育胞质不同。  相似文献