Two forms of sustained xanthophyll cycle-dependent energy dissipation in overwintering Euonymus kiautschovicus

Seasonal differences in PSII efficiency (F_v/F_m), the conversion state of the xanthophyll cycle (Z + A)/ (V + A + Z), and leaf adenylate status were investigated in Euonymus kiautschovicus. On very cold days in winter, F_v/F_m assessed directly in the field remained low and Z + A high throughout day and night in both sun and shade leaves. Pre-dawn transfer of leaves from subfreezing temperatures in the field to room temperature revealed that recovery (increases in F_v/F_m and conversion of Z + A to violaxanthin) consisted of one, rapid phase in shade leaves, whereas in sun leaves a rapid phase was followed by a slow phase requiring days. The pre-dawn ATP/ADP ratio, as well as that determined at midday, was similar when comparing overwintering leaves with those sampled in the summer, although pre-dawn levels of ATP + ADP were elevated in all leaves during winter relative to summer. After a natural transition to warmer days during the winter, pre-dawn F_v/F_m and Z + A in shade leaves had returned to values typical for summer, whereas in sun leaves F_v/F_m and Z + A levels remained intermediate between the cold day in winter and the summer day. Thus two distinct forms of sustained (Z + A)-dependent energy dissipation were identified based upon their differing characteristics. The form that was sustained on cold days but relaxed rapidly upon warming occurred in all leaves and may result from maintenance of a low lumenal pH responsible for the nocturnal engagement of (Z + A)-dependent thermal dissipation exclusively on very cold days in the winter. The form that was sustained even upon warming and correlated with slow Z + A to violaxanthin conversion occurred only in sun leaves and may represent a sustained engagement of (Z + A)-dependent energy dissipation associated with an altered PSII protein composition. In the latter, warm-sustained form, uncoupler or cycloheximide infiltration had no effect on the slow phase of recovery, but lincomycin infiltration inhibited the slow increase in F_v/F_m and the conversion of Z + A to violaxanthin.     

风和风沙流对不同固沙植物生理状况的影响

在野外风洞条件下,对风和风沙流影响固沙植物的生理状况进行了研究。结果表明：风和风沙流对不同植物的影响不同,风对结皮和苔藓的影响在于吹蚀和干燥,对草本和灌木的影响主要是：１．通过迫使气孔关闭、降低叶温和胞间ＣＯ２浓度来抑制光合作用;２．加强蒸腾作用,减小水分利用率;３．降低叶片水势和土壤含水量,从而加强干燥作用。而风沙流对结皮和苔藓的影响主要在于剥蚀和堆积,对草本和灌木的影响主要是机械损伤作用,对光合和水分利用的影响将更加剧烈。不同类型植物对两种胁迫的适应程度不同。     

晋冀鲁豫接壤区生态环境现状评价

对“中国资源、生态环境预警研究”的有关方法,建立了晋冀鱼豫接壤区１１个地、市的生态环境质量评价指标体系,并用层次分析法,对１１个地市作出的生态环境质量进行了排序,以表征该区经济持续发展能力及其潜力。     

Nutrient concentration in shape Sphagna at increased N-deposition rates and raised atmospheric CO2 concentrations

Sphagnum fuscum, S. magellanicum, S. angustifolium and S. warnstorfii were treated with N deposition rates (0, 10, 30 and 100 kg ha^-1 a^-1) and with four atmospheric CO₂ concentrations (350, 700, 1000 and 2000 ppm) in greenhouse for 71–120 days. Thereafter, concentrations of total N, P, K, Ca and Mg in the capitulae of the Sphagna were determined. The response of each species to N deposition was related to ecological differences. With increasing N deposition treatments, moss N concentrations increased and higher N:P-ratios were found, the increase being especially clear at the highest N load. Sphagnum fuscum, which occupies ombrotrophic habitats, was the most affected by the increased nitrogen load and as a consequence the other elements were decreased. Oligotrophic S. magellanicum, wide nutrient status tolerant S. angustifolium and meso-eutrophic S. warnstorfii tolerated better increased N deposition, though there were increased concentrations of Ca and Mg in S. warnstorfii and Mg in S. magellanicum. Nitrogen and P concentrations decreased with raised CO₂ concentrations, except for S. magellanicum. This seems to be the first time this kind of response in nutrient concentrations to enhanced CO₂ concentration has been shown to exist in bryophytes. The concentration of K clearly decreased in S. fuscum as did the concentration of Mg in the other Sphagna with increasing CO₂. Sphagnum angustifolium and S. magellanicum, which are the less specialized species, were the least affected by the CO₂ treatments.     

Lactate Production from Glucose and Response to Insulin in Perifused Adipocytes from Mesenteric and Epididymal Regions of Lean and Obese Rats

Lactate, an important metabolic substrate for peripheral tissues and the liver, is released in significant amounts from adipose tissue. Using a perifusion system, we measured lactate production from glucose and response to insulin in isolated mesenteric and epididymal adipocytes removed from fed or fasted male Wistar rats at two stages of growth and development: (a) lean rats (7 weeks to 9 weeks old, weighing ～250 g), and (b) fatter rats (6 months to 8 months old, weighing ～550 g). The results show that lactate production in perifused adipocytes is regulated by the prior nutritional state of the animals, by the adipose tissue region, and by the presence of insulin in the perifusate. In fat cells from lean rats, basal lactate production was significantly higher (p<0.05) in mesenteric cells when compared with epididymal cells, both in the fed state (7.8 nmol/10⁷ fat cells per minute vs. 2.9 nmol/10⁷ fat cells per minute) and after 2 days of fasting (13.6 nmol vs. 3.5 nmol). When the response to 1 mU/mL insulin was studied, however, the relative increase in lactate production produced by insulin was greater in the epididymal cells than in the mesenteric cells, in both the fed (194% vs. 91% over basal, respectively) and fasted (360% vs. 55% over basal, p<0.05) state. When larger epididymal adipocytes from fatter rats were compared with an equal number of smaller epididymal cells from leaner rats, the larger cells produced 4.99 nmol of lactate/10⁷ fat cells per minute, whereas the smaller cells produced 2.93 nmol (p=0.08). Large fat cells showed a small and nonsignificant response to insulin in either type of cell (epididymal vs. mesenteric) or nutritional state (fed vs. fasted). This study indicates that distinct regional differences exist in lactate production and response to insulin. Mesenteric adipose tissue, which drains directly into the portal vein and provides substrates to the liver, may be an important source of lactate for the hepatic processes of gluconeogenesis and glycogenesis.     

The regulation of brood reduction in Booted Eagles Hieraaetus pennatus through habitat heterogeneity

Brood reduction, the death of one or more chicks through siblicide or starvation, can occur through density‐dependence in fecundity. Brood reduction may arise in territorial breeding systems either as a response to a high level of territorial interference in a situation of high density or as a result of habitat heterogeneity. To test the predictions of the two main hypotheses that attempt to explain how density‐dependent fecundity is generated, the Habitat Heterogeneity Hypothesis (HHH) and the Individual Adjustment Hypothesis (IAH), we analysed the relationship between density and fecundity in an expanding population of Booted Eagles in Doñana National Park, Spain, using an 18‐year data series. We also studied the occurrence and frequency of brood reduction in the same Booted Eagle population to appreciate further its effects and the factors that influence its occurrence and frequency. Our results support the HHH in the present situation of high density, as fecundity in the better territories (older and more frequently occupied) was higher than in low quality territories and was not affected by population density in high density periods. Nevertheless, the fecundity of high quality territories was affected (although not significantly) by population density in periods of low density, suggesting that the IAH was supported when only high quality territories were occupied. Older territories were used more frequently and chicks in these areas hatched earlier and suffered lower mortality than in new territories. We found a significant negative relationship between mean fecundity and its skewness, a finding that also supports HHH. During years of food shortage, less frequently occupied territories suffered higher rates of brood reduction. Brood reduction in this Booted Eagle population was a consequence of the heterogeneous structure of the habitat, with some territories having a higher probability of brood reduction than others. Parental nutritional condition did not affect brood reduction. The effect of brood reduction on nestling quality and population dynamics is also discussed.     

The changing otter population of Britain 1700–1989

Otters Lutra lutra were persecuted increasingly in Britain for fishery protection and for sport throughout the 18th and 19th centuries. There are indications of a population recovery occurring during the 1914–1918 war with the temporary cessation of hunting and keepering. Intensive otter hunting with packs of hounds throughout the 1920s and 1930s appears to have stressed the population by altering the age structure. A catastrophic decline occurring simultaneously over England, Wales and southern Scotland, but most severe in the south-east and starting in 1957–1958, appears to have been triggered in this stressed population by a single new factor, pollution of the rivers by organochlorine insecticides. The trough in the decline may have occurred around 1977— 1979. The first signs of rivers being re-occupied by otters have been seen by the early 1980s and partial recovery seems possible with legal protection and improved water quality.     

Distribution, endemism and threat status of freshwater fishes in the Western Ghats of India

Aim To study (1) the large-scale distribution patterns of freshwater fishes in the Western Ghats of India; (2) the endemism and uniqueness of the fishes in various zones; and (3) the threat status of fishes by categorizing them under low risk (LR), vulnerable (VU), endangered (EN) and critically endangered (CR). Location The Western Ghats of India. Methods The scientific literature describing the freshwater fishes of the Western Ghats was reviewed. Data describing the lists of the species were extracted and complied. The species accumulation curve was plotted using Michaelis–Menten-like equation. The Western Ghats was divided into six zones and similarity of the species was calculated using Jacquard's index. Results Literature to date records 288 species belonging to 12 orders, 41 families and 109 genera, of which 118 species are endemic and 51 are unique. However, the species accumulation curve shows that there might be 345 species in this region, indicating that 16% species have not been recorded to date. An analysis of the distribution pattern of fishes in the Western Ghats suggests that the southern region is more diverse than the northern and central regions. The southern region shows high endemism and high uniqueness while the northern region shows high endemism but less uniqueness. The similarity index between the zones indicates that as the distance between the zones increases similarity decreases. The status of 105 of 288 species was not known due to data deficiency but among the remaining 183 species, 58 species were categorized as LR, 41 as VU, 54 as EN, 24 as CR while the remaining six species were introduced. Conclusions The distribution patterns of fishes in the Western Ghats are discussed in accordance with the geography of Western Ghats, its climatic conditions and ‘Satpura Hypothesis’. The threat status of fishes found in Western Ghats suggests that at least 41% of fish fauna is threatened by either being VU, EN or CR. Implication of potent conservation measures is necessary to conserve the fish fauna of Western Ghats.     

重庆市消化内镜医师执业状况调查报告

目的:评价重庆市各级内镜医疗机构医疗执业现状,分析导致医疗执业状况不佳的原因,为改善医疗执业状况和医患关系,促进我国医疗执业健康、和谐发展提供参考。方法:对重庆市137家已开展消化内镜诊疗的医院,506名内镜医师进行调查,调查内容主要包括重庆内镜医师当前的基本素质状况以及医师们如何看待所面临的卫生改革、所处执业状况、管理体制、行业内协会职能、执业内镜医师法、继续教育培训等。结果:54.81%消化内镜医师对自己的工作表示满意,40.13%的医师感觉工作一般;在对医疗事故的调查中,遇到和未遇过医疗事故的比例分别为5%和95%;目前主要困惑重庆消化内镜医师的是以下问题:缺乏休息时间、工作较大强度,比例占到36.09%。结论:应改善消化内镜医师执业环境,缓解消化内镜医师工作压力,有效地发挥媒体导向作用,加强法制建设。