上海崇明岛水杉人工林生物量方程构建及固碳潜力研究

水杉(Metasequoia glyptostroboides)因其生长快递、冠型优美、适应性强等特点,成为亚热带和温带地区最重要的用材林和景观林树种之一。在本研究中,以上海崇明岛东平国家森林公园不同龄级水杉林分为研究对象,构建水杉人工林异速生长方程,估测幼龄林(8年生)、中龄林(15年生)、成熟林(30年生)3个不同年龄阶段林分地上部分生物量、碳储量和年固碳量,并比较不同龄级林分的固碳能力。结果显示,水杉地上部分生物量及干、枝、叶部分生物量与胸径呈显著指数关系(r2=0.89～0.99,P<0.001)。2011年,水杉幼龄林、中龄林和成熟林地上部分生物量分别为13.11、29.76和64.93t/hm2,地上部分年固碳量分别为3.57、2.41和1.52t/hm2/a。对比相关研究发现,降雨量的差异可能是我国不同地区水杉生物量差异的主要因素。研究结果将为华东地区乃至全国营造和经营管理水杉人工林,尤其是水杉碳汇林,提供基础数据和理论依据。     

"Candidatus Phlomobacter fragariae" Is the Prevalent Agent of Marginal Chlorosis of Strawberry in French Production Fields and Is Transmitted by the Planthopper Cixius wagneri (China)

ABSTRACT Marginal chlorosis has affected strawberry production in France for about 15 years. A phloem-restricted uncultured bacterium, "Candidatus Phlomobacter fragariae," is associated with the disease. A large-scale survey for marginal chlorosis in French strawberry production fields and nurseries by polymerase chain reaction amplification of "Ca. P. fragariae" 16S rDNA revealed that symptoms of marginal chlorosis were not always induced by "Ca. P. fragariae" and that the stolbur phytoplasma could induce identical symptoms. "Ca. P. fragariae" was found to be predominant in strawberry production fields, whereas the stolbur phytoplasma was predominantly detected in nurseries. Two transmission periods of the disease, one in spring and the other from late summer to early fall, were evident. Cixius wagneri planthoppers captured on infected strawberry plants were demonstrated to be efficient vectors of "Ca. P. fragariae." The involvement in natural disease spread of the whitefly Trialeurodes vaporariorum, previously shown to acquire and multiply "Ca. P. fragariae" under greenhouse conditions, remains uncertain.     

Inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase lower fecundity in the German cockroach: correlation between the effects on fecundity in vivo with the inhibition of enzymatic activity in embryo cells

The enzyme 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase is crucial to insect development and reproduction, as revealed by the sterilising properties of some specific inhibitors of it. In the present paper, we study the sterilising effects of a number of HMG-CoA reductase inhibitors on the German cockroach, Blattella germanica (L). The inhibitors tested were naringenin, lovastatin, mevastatin, simvastatin, atorvastatin and fluvastatin. The first two compounds were ineffective or scarcely effective as HMG-CoA reductase inhibitors. The most active compounds in vivo were fluvastatin and atorvastatin, followed by simvastatin and mevastatin. They were equally ranked when tested as HMG-CoA reductase inhibitors in the B germanica embryonic derived cell line UM-BGE-1. This suggests that this cell line may be an appropriate tool for testing HMG-CoA reductase inhibitors and so to predict their properties as insect sterilising agents with insecticide potential.     

Oxidative stress in the erythrocytes of cattle intoxicated with Senecio sp

BACKGROUND: Intoxication caused by Senecio sp is characterized by irreversible damage to liver cells and may be associated with oxidative stress. OBJECTIVES: The aim of this study was to evaluate the effects of intoxication by Senecio sp on lipoperoxidation, antioxidant defenses, and the osmotic resistance of erythrocytes in cattle. METHODS: Blood samples from 30 intoxicated animals (group 1) and 30 healthy animals (group 2) were analyzed. The diagnosis of poisoning by Senecio sp was based on histopathologic lesions verified through hepatic biopsy. The following biochemical parameters of oxidative stress in the erythrocytes were determined: thiobarbituric acid-reactive substances (TBARS), copper-zinc superoxide dismutase (CuZnSOD) activity, and nonprotein sulfhydryl (NPSH) groups. Erythrocyte osmotic fragility also was evaluated. RESULTS: TBARS concentration and CuZnSOD activity were significantly (P <.001) higher in group 1 when compared with group 2. The concentration of erythrocyte NPSH groups was significantly (P <.03) lower in group 1 when compared with group 2. Osmotic fragility was more pronounced in the erythrocytes of group 1 when compared with group 2 (P < .001). CONCLUSIONS: The results of this study indicate that poisoning by Senecio sp causes an increase in lipoperoxidation, oxidation of NPSH groups, and consequently, oxidative stress in bovine erythrocytes that may contribute to hemolysis. These findings may contribute to a better understanding of the mechanisms involved in cell damage in animals intoxicated by Senecio sp.     

Long-term monitoring of classical swine fever in wild boar (Sus scrofa sp.) using serological data

In the European Community, epizootics of classical swine fever (CSF) in the wild boar (Sus scrofa) are compulsorily monitored because transmission may occur between wild boars and domestic pigs, causing heavy economic losses to the pork industry. The estimation of incidence in populations of wild boars is generally based on viroprevalence. However, viral isolation becomes rare when the incidence is low because the virus cannot be detected for more than a few weeks following infection. On the contrary, seroprevalence is detectable at low incidence levels, because antibodies can be detected for the lifetime of the infected animal. We thus attempted to analyse the long-term evolution of CSF incidence using serological data. The data came from France, where CSF had been monitored from 1992 to 2002, and where the virus has not been detected since 1997. We assumed that the overall seroprevalence would estimate the proportion of immune wild boars, that seroprevalence in juveniles would approximate incidence and that seroprevalence in different age classes would show the evolution of incidence in a given cohort. Spatial and temporal trends of incidence and seroprevalence were explored using logistic modelling and the spatial trend was analysed using polynomial regression. In 1992, incidence peaked in the northern area. After 1993, incidence decreased but remained the highest in the northern area. After 2000, no seropositive juvenile was observed, suggesting the extinction of the epizootic. Our results support the reliability of serological monitoring since it allowed a longer detection of viral transmission and provided more information on the spatio-temporal evolution of incidence than did viral isolation. We advocate that the highest persistence of infection in northeastern France is not independent from infection persistence in Reinland-Pfalz (Germany). Such persistence may be due to favourable local conditions and/or the social organisation of wild boars.     

Bioassay method for testing Fusarium wilt disease tolerance in transgenic banana

Fusarium wilt caused by the fungus, Fusarium oxysporum f.sp. cubense is a major factor limiting commercial banana production in Malaysia. Field evaluation of banana plants for Fusarium wilt disease has not been effective as the infection period is slow and other variables such as distribution of inoculum concentration is difficult to control. Therefore, a study was carried out to develop a semi-qualitative bioassay for early and rapid susceptibility tests against Fusarium wilt disease in banana plantlets. The induction of sporulation and germination of Foc race 1 (VCG 01217) were firstly determined. Then, the effect of inoculum density of fungal spores on the magnitude of infection in Pisang Rastali (AAB) plantlets was carried out. The concentration of hydrogen peroxide (H₂O₂) and other enzyme activities such as phenylalanine ammonia lyase (PAL), chitinase, glucanase, peroxidase (PER) and polyphenol oxidase (PPO) in infected roots of banana plants were determined to relate to the levels of tolerance or susceptibility to Fusarium wilt disease. Using similar conditions, transgenic Pisang Rastali (AAB) was tested to investigate the effectiveness of this bioassay. Hydrogen peroxide and phenylalanine ammonia lyase is the most sensitive compound and enzyme detectable after inoculated with Fusarium spores. The chitinase, β-1,3-glucanases, peroxidase and polyphenol oxidase enzymes activity of transgenic plants were higher than untransformed plantlets. The results obtained indicate that the use of these biochemical parameters has the potential to predict the levels of tolerance or susceptibility to Fusarium wilt disease in other banana cultivars.     

Changes of Heavy Metal and PCB Contents in Surficial Sediments of the Barcelona Harbour after the Opening of a New Entrance

Water, Air, & Soil Pollution - The Barcelona harbour is one of the biggest and most important in commercial and passenger traffic in the Mediterranean Sea. In 2003, construction works for the...     

Forest recovery since 1860 in a Mediterranean region: drivers and implications for land use and land cover spatial distribution

Context

Land use and land cover (LULC) change is a major part of environmental change. Understanding its long-term causes is a major issue in landscape ecology.

Objectives

Our aim was to characterise LULC transitions since 1860 and assess the respective and changing effects of biophysical and socioeconomic drivers on forest, arable land and pasture in 1860, 1958 and 2010, and of biophysical, socioeconomic and distance from pre-existing forest on forest recovery for the two time intervals.

Methods

We assessed LULC transitions by superimposing 1860, 1958 and 2010 LULCs using a regular grid of 1 × 1 km points, in a French Mediterranean landscape (195,413 ha). We tested the effects of drivers using logistic regressions, and quantified pure and joint effects by deviance partitioning.

Results

Over the whole period, the three main LULCs were spatially structured according to land accessibility and soil productivity. LULC was driven more by socioeconomic than biophysical drivers in 1860, but the pattern was reversed in 2010. A widespread forest recovery mainly occurred on steeper slopes, far from houses and close to pre-existing forest, due to traditional practice abandonment. Forest recovery was better explained by biophysical than by socioeconomic drivers and was more dependent on distance from pre-existing forest between 1958 and 2010.

Conclusions

Our results showed a shift in drivers of LULC and forest recovery over the last 150 years. Contrary to temperate regions, the set-aside of agricultural practices on difficult land has strengthened the link between biophysical drivers and LULC distribution over the last 150 years.

     

Characterization of sex, age, and breed for a population of canine leishmaniosis diseased dogs

Our study of a large canine population investigated whether the development of symptomatic canine leishmaniosis revealed any predilection for sex, age, or breed. Included in the study were 390 leishmaniosis-affected dogs that had been treated at the Hospital Clínic Veterinari attached to the Universitat Autònoma de Barcelona. Of the diseased dogs, 238 were male (61%) and 152 were females (39%), whereas percentages for males and females in the overall reference population of dogs treated at this unit were 53% and 47%, respectively, (P<0.05). Age distribution was bimodal, with the highest prevalence of the disease occurring at 2-4 years of age and a secondary peak occurring at seven years or over. The over represented breeds were the German shepherd (13.6% versus 6.35%, P<0.001), the Rottweiler (13.1% versus 3.0%, P<0.001), and the Boxer (7.9% versus 4.7%, P=0.002), whereas the underrepresented breeds were the Yorkshire terrier (0.5% versus 6.5%, P<0.001), and the Poodle (0.3% versus 3.0%, P<0.001).     

Placental transfer of etomidate in pregnant ewes after an intravenous bolus dose and continuous infusion

Etomidate (ETO) is a short-acting intravenous (IV) anaesthetic characterised by cardiopulmonary stability and favourable pharmacokinetics. Although ETO has been used satisfactorily in obstetrical anaesthesia, little is known about placental transfer and the drug's pharmacokinetics in the fetus. Placental transfer in pregnant ewes has been evaluated following the administration of an IV bolus of 1mg/kg ETO; and after a 1-h infusion of 100 microg/kg min(-1) ETO preceded by an IV bolus of 1mg/kg. In ewes, ETO concentration and AUC were higher than those found in fetuses. After the ETO bolus dose, the fetus:ewe AUC ratio was 0.45+/-0.32, and the mean residence time (MRT) was 20+/-7 min for dams and 22+/-3 min for the fetuses. After ETO infusion, the AUC ratio was 0.37+/-0.08, and MRT was 46+/-12 min for ewes and 46+/-22 min for fetuses. Although ETO crosses the placenta very rapidly and reaches the fetus in high amounts, a certain placental barrier effect limits its transfer. There is no evidence of cumulative effects of the drug in the fetus as fetal ETO elimination was as rapid as in the dam.