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1.
Shipley Amy A. Sheriff Michael J. Pauli Jonathan N. Zuckerberg Benjamin 《Landscape Ecology》2022,37(3):779-793
Landscape Ecology - Variability in temperature and snow cover are characteristics of high-latitude environments that impose significant pressures on overwintering species. To cope with increased... 相似文献
2.
MU Xin-bing LI Su-zhi GAO Yu-qi LIU Fu-yu YE Gang-lin TANG Hong-ya ZHU Dan ZHOU Xiao-bo CHEN Guang-lin 《园艺学报》2003,19(8):1106-1108
AIM:To explore the pathogenic mechanism of high altitude pulmonary edema(HAPE).METHODS:Haemodynamic changes and effects of 100 percent oxygen breathing were measured by Swan-Ganz thermistor catheters, high altitude healthy volunteers were served as controls.RESULTS:The important features of haemodynamic changes in HAPE: (1)Pulmonary arterial pressure was raised; (2)Pulmonary arterial resistance and cardiac output were raised; (3)Pulmonary artery wedge pressures and right atrial pressure were normal; (4)Pulmonary arterial pressure and resistance were induced by oxygen breathing.CONCLUSIONS:The normal pulmonary artery wedge pressures with a high cardiac output indicated that HAPE was recognized as a form of noncardiogenic pulmonary edema. The pulmonary hypertension may play an important role in the development of HAPE. 相似文献
3.
Domenica Manicacci Isabelle Olivieri Véronique Perrot Anne Atlan Pierre-Henri Gouyon Jean-Marie Prosperi Denis Couvet 《Landscape Ecology》1992,6(3):147-159
Distribution of genetic diversity in a landscape depends on both within and among population processes. Selective pressures within populations have traditionally been studied by population genetics, which usually assumes that populations are at equilibrium. However, when selection pressures within and among populations are different, landscape processes are required to define an equilibrium (landscape being defined as the habitat of a set of populations called a metapopulation, and populations will differ depending on their situation in the landscape, i.e. their age and the state of neighboring populations). We examine reproduction systems and life history traits, for which variation depends on landscape processes. Predictions of their states in a metapopulation are drawn from theoretical models, and confronted to observations collected in natural populations. 相似文献
4.
Forests used to be the main field of interest for rural communities, but now they attract the attention of urbanites too. The forest–public relationship is important as forests protect water resources, preserve the soil and increase its productivity, provide positive effects on climate and health in general, and can be used for recreation and tourist purposes. This study aims at assessing how the current rapid urbanization process in Turkey affects forests. Urban requirements such as biomass for heating, education facilities, settlements, recreation, tourism and employment exert various pressures on the forest. In this study we assessed these pressures and suggest that forest legislations should be developed to respond to expectations of urbanites from forests, new recreation areas should be developed and urbanites’ interest in and knowledge of the forests should be increased, where all social groups including the forestry authority should work together. 相似文献
5.
The influence of harvest date and storage method on bruises sensitivity of apples was investigated. The cultivars ‘Braeburn’, ‘Jonagold’ and ‘Golden Delicious’ were harvested at three times in an interval of 10 days. Fruits have been stored at 2°C in normal atmosphere (cold storage) or in film bags (CA-/ULO-storage; CA?=?Controlled Atmosphere, ULO?=?Ultra Low Oxygen) for three months. Monthly fruits were bruised by a penetrometer applying a range of pressures. One day later the appearance of bruises were evaluated. Increasing pressures resulted in bruises of increasing severity. Early harvest led to less severe bruises. No differences were observed in storage conditions, but duration of storage increased bruise sensitivity of ‘Braeburn’. In comparison of the three cultivars ‘Braeburn’ was less sensitive than ‘Jonagold’ and ‘Golden Delicious’. 相似文献
6.
Ripening of mango fruit is markedly delayed when the pressure in the storage chamber is reduced below 100 mm Hg, and fruit storage life is thus prolonged. The prolongation of storage life is inversely related to the pressure; control fruit stored at 760 mm Hg started to ripen after 16 days in storage at 13°C, while fruit stored at 100 and 75 mm Hg after 25 and 35 days, respectively. Fruit stored at 50 mm Hg remained unripe for 35 days. No effect on ripening was recorded at pressures above 250 mm Hg, while at pressures below 50 mm Hg the fruit desiccated. All fruits stored at subatmospheric pressure ripened 3–4 days after transfer to shelf life at 25°C. However, green mango fruits of the colored cultivars like ‘Haden’ and ‘Maya’, stored at subatmospheric pressure for a prolonged period, did not develop the proper red or orange color during shelf-life, but turned pale yellow instead. Treatment with ethylene upon removal from storage slightly improved color development in these fruits. 相似文献
7.
The influence of foliar fertilization and storage method on the bruise sensitivity of apples was investigated. The foliar fertilization was carried out with calcium, manganese or zinc by the cultivars ‘Braeburn’ and ‘Jonagold’. Fruits have been stored at 2°C in normal atmosphere (cold storage) or in film bags (CA-/ULO-storage (CA?=?controlled atmosphere, ULO?=?ultra low oxygen) for three months. Monthly fruits were bruised with a penetrometer applying a range of pressures. One day later the appearance of bruises was evaluated. Increasing pressures resulted in bruises of increasing severity. Foliar fertilization had no effect on the bruise susceptibility of both cultivars. The application of manganese and zinc led to an increase of manganese and zinc concentration in the leaves. The calcium concentration of fruits was not affected by the manganese and zinc application. The application of calcium increased the calcium concentration in the leaves and fruits to a lower degree, but no effect on the bruise sensitivity could be observed. No differences were observed in storage conditions, but duration of storage increased the bruise sensitivity of ‘Braeburn’. In comparison of the cultivars ‘Braeburn’ was less sensitive than ‘Jonagold’. 相似文献
8.
Tomato fruits were stored in a low (hypobaric) pressure system (LPS), ventilated with different oxygen and ethylene concentrations. The effect of these factors on different ripening-parameters (respiration, chlorophyll degradation, lycopene synthesis, fruit firmness and pectic enzyme activities) was investigated. Ethylene had a definite effect on most but not all of these parameters, even at the low oxygen pressure used in this system. The reduction in oxygen as well as in ethylene partial pressures was responsible for the observed retardation of tomato fruit ripening at hypobaric conditions. 相似文献
9.
观察３０例门诊病人服用灵芝口服液一个疗程后的症状改善情况。结果表明：灵芝口服液对植物性神经紊乱症疗效较好,症状改善明显;对冠心病、脑动脉硬化症、脑血栓后遗症及慢性支气管炎等也有一定疗效,其症状均有不同程度的改善;高血压症患者舒张压、收缩压及高血脂症患者的血清胆固醇、甘油三脂均下降,趋于正常（Ｐ＜００１）。 相似文献
10.
J.B. O&#x;Loughlin 《Scientia Horticulturae》1978,9(1):41-46
This study involved harvesting samples of ‘Richared’ and ‘Starkrimson’ from Tasmanian orchards on 3 harvest dates in 2 consecutive years. The storage performance was assessed after 12 weeks cool storage in 1974 and 18 weeks in 1975.Flesh pressures at harvest were usually higher in ‘Richared’ than in ‘Starkrimson’. The incidence of superficial scald did not differ between the 2 cultivars. ‘Richared’ was far more susceptible to watercore at harvest and breakdown ex store than ‘Starkrimson’. For these reasons, the timing of harvest was more critical for ‘Richared’ than for ‘Starkrimson’. 相似文献
11.
《Scientia Horticulturae》2005,103(2):249-255
Bromeliad growers report severe leaf quality problems for Aechmea cultivars grown under commercial greenhouse conditions. In this research, a leaf damage ‘sensitive’ and ‘insensitive’ A. cultivar were compared for their C-metabolism and hydrophysiology under these greenhouse conditions. Stomata opening index indicated CAM (Crassulacean acid metabolism) for both cultivars, with 45–50% open stomata around 4:00 a.m. and 5–10% in the afternoon. Malic and citric acid were the major organic acids present in the leaves, with diurnal malic acid accumulation during the night. The leaf damage ‘sensitive’ cultivar showed higher malic acid accumulation than the ‘insensitive’ cultivar (200 μmol/gfw versus 170 μmol/gfw). Leaf osmotic potential and turgor pressure were linked with diurnal malic acid fluctuations: organic acid accumulation during the night generated high leaf turgor pressures (up to +0.86 MPa).A leaf damage sensitivity test was designed and confirmed previous experiences of several bromeliad growers. Both cultivars showed higher leaf damage percentages (98 and 78%) when leaf malic acid accumulation was high. We attribute this elevated sensitivity to lethal turgor pressures and consider them to be caused by the water capturing mechanism generated by high organic acid accumulation. Under current greenhouse conditions, this water capturing mechanism can be disastrous for plant leaf quality. Especially, under high relative humidity, hindering plant transpiration and stimulating water uptake by dew formation, leaf quality could be endangered. 相似文献
12.
果品产业高质量发展是兼顾经营者、生产者、消费者利益的更高层面的发展;推动山东果品产业高质量发展对于应对产业面临的挑战与压力、促进乡村振兴、落实新发展理念、增加农民收入等都具有十分重要的意义;山东果品产业发展水平具备了由追求高产量向追求高质量发展转变的客观条件;推动山东果品产业高质量发展,需要在充分发挥市场配置资源的决定性作用的同时,更好地发挥政府作用。 相似文献
13.
Context
National borders remain an impediment to efficient preservation of biodiversity and ecosystems. For transboundary water resources, conservation planning becomes more challenging, as competitive interests make these sensitive and productive systems focal points of interstate conflicts.
ObjectivesThis global study aims to explore the patterns of protection coverage for transnational lakes and their catchments, highlighting gaps and inconsistencies at the protection observed among countries sharing the same lake.
MethodsIdentifying 793 transnational lakes globally, we initially investigated protection coverage at their water bodies. Next, we explored protection coverage patterns across each lake’s catchment, in which we also quantified human pressures’ extent and intensity. Socio-economic and political parameters were examined as potential predictors of the observed patterns.
ResultsOnly half of the world’s transnational lakes are fully or partly covered by existing protected areas. Our analysis demonstrated that in only 37% of the protected transnational lakes, the extent of protection coverage was similar in the neighboring counties sharing the same lake. Protection patterns were not driven by the relative area of the transnational lakes found in the neighboring countries. Moreover, protection cover focuses mainly on lakes’ water surface ignoring the terrestrial surroundings, while more than 75% of the catchments are subjected to intense human pressures.
ConclusionsProviding the first overview of the protection gaps of transnational lakes globally, we highlight a failure of policy responses to cross-border conservation of sensitive freshwater ecosystems. Consequently, such limitations are likely to loom risks for human well‐being and for the initiation of intense conflicts.
相似文献14.
Tree ordinances can be an effective means of preserving urban forests in the face of development pressures. Despite this, they also have the potential to be divisive among the public - especially when applied to privately-owned land. In this study we surveyed 1716 Florida urban residents to understand how they value regulation and management of the urban forest. Specifically, we asked about: tree protection ordinances, incentive programs to manage or plant trees, justification for tree removal, and development. Most respondents supported tree protections, even when applied to trees on their own property or when they had the potential to limit development activities. Additionally, there was limited support for removing healthy trees for development. Respondents supported the use of funds for urban forestry efforts – particularly at the local or state level. 相似文献
15.
AIM:To investigate the functional changes and histopathological basis of Oddi’s sphincter under hypercholesterolemia. METHODS:Twenty - four New Zealand rabbits were equally divided into be groups ran- domly. Experimental groups Ⅰ and Ⅱ fed with cholesterol - added forage for 4 and 8 weeks respectively before sacri- ficed. Images, functions and histopathological characteristics of Oddi’s sphincters of experimental groups were studied and compared with control group by cholangiography, catheter manometry, and quantitative analysis of nitric oxide synthase. RESULTS: The hasal pressures of proximal low - pressure segment of Oddi’s sphincter of hath experimen- tal groups Ⅰand Ⅱ (20.9±6.1 mmHg, 25 .6±9.1 mmHg, respectively) were higher than those of control group sig- nificantly (11.7±2.8 mmHg, P < 0.01, P < 0.01 ). The hasal pressures of distal high - pressure "valve" segment of both experimental pops (138 .4±45. 5 mmHg and 144. 5 ±40 .4 mmHg, respectively) were significantly higher than those of coned group (69.3±9.8 mmHg, P < 0.01 and P<0.01). The gallbladder volUmes of experimental group Ⅰ and Ⅱ (3.4±1.0 mL and 3.9±1.9 mL) were significantly larger than those of control group (2.0 ±1.9 mL, P < 0.05 and P < 0.01 ). Between groups there were no significant differences in nitric oxide synthase con- tents. Enlargement of the cell volume, wavy distortion of the cell membrane, loosening and disarrangement of myofila- ment, uneven in size and distribution of dense body, angulation of longitudinal axis between dense body and myofila- ment, swelling, congregated at one end of nucleoulus and disappearance of cristae of plasmosomes and concertration of chromosome at nucleolus margin were observed in experimental groups under electron-microscope. CONCLUSION: The diastole function of Oddi’s sphincter could be damaged by hyperecholesterolemia, inducing a functional disorder of Oddi’s sphincter with increased resistance in bile excretion. The result is retertion of bile in the gallbladder. 相似文献
16.
围绕基因枪微粒的制备、大白菜小孢子对基因枪轰击的耐受能力以及小孢子的胚胎发生能力开展研究,初步建立了以小孢子为外植体的遗传转化体系。高胚胎发生的大白菜材料‘CC-4’的小孢子在基因枪7.58×10~6 Pa爆破压力,9 cm的轰击距离下,利用直径0.6μm,亚精胺包裹的金粒子微弹以每次500μg的金粒子量连续轰击5次,小孢子活力不受影响,培养1 d后GUS基因瞬时表达检测,平均每皿可获得20个以上转化小孢子;小孢子培养15 d后成功获得胚状体,GUS基因瞬时表达检测,平均每皿最多获得4个遗传转化的胚状体,40个花蕾可获得20个以上转化胚状体。初步探讨基因枪法介导大白菜小孢子结果表明:大白菜小孢子数量庞大易收集,可耐受基因枪的多次轰击,并能继续保持胚胎发生的能力,作为新尝试的遗传转化受体,有可能是解决白菜类作物再生困难,提高转基因效率的有效手段。 相似文献
17.
Uncertainty analysis of a spatial habitat suitability model and implications for ecological management of water bodies 总被引：3，自引：0，他引：3
Guda E. M. Van der Lee Diederik T. Van der Molen Henk F. P. Van den Boogaard Hanneke Van der Klis 《Landscape Ecology》2006,21(7):1019-1032
Habitat suitability index (HSI) models have been generally accepted in ecological management as a means to predict effects
of pressures and restoration measures on habitats and populations. HSI-models estimate habitat suitability from relevant habitat
variables. Because outcomes of HSI-studies may have significant consequences, it is crucial to have insight into the uncertainties
of the predictions. In this study a method for uncertainty analysis, using Monte Carlo simulations, was developed and applied
for a HSI-model of pondweed (Potamogeton pectinatus) in Lake IJsselmeer, The Netherlands. Uncertainties in both habitat model functions and in input data were considered. The
magnitude of the uncertainties in model functions were estimated by a panel of experts, and the uncertainty was highest at
intermediate values of the suitability index (0.4–0.6). Uncertainty in the predicted habitat suitability is spatially correlated
with variations in environmental habitat variables such as water quality and substrate. The estimated uncertainty may be considered
acceptable for the purposes of water management, namely directing ecological rehabilitation and conservation activities. However,
the uncertainties may be too high to meet the accuracy requirements of legislation such as the EU Bird and Habitat directive. 相似文献
18.
Nihal C. Rajapakse Chuanjiu He Luis Cisneros-Zevallos Fred T. Davies Jr. 《Scientia Horticulturae》2009
The primary objective of this research was to investigate how low pressure (hypobaria) and low oxygen (hypoxia) affect functional phytochemicals and the nutritional quality of ‘Red Sails’ lettuce (Lactuca sativa L.). Plants were grown under two levels of total gas pressure (reduced or ambient (25 or 101 kPa, respectively)) at three levels of O2 partial pressures (low, medium or ambient (6, 12 or 21 kPa, respectively)). Hypoxia effects on nutritional and functional phytochemicals were more pronounced than hypobaria effects. Regardless of the total pressure, hypoxia, in general, enhanced leaf anthocyanin levels, enhanced total phenolic compounds, enhanced carbohydrate concentration and enhanced free radical scavenging capacity of lettuce but reduced leaf mineral concentration. Hypoxia increased the ethylene production of plants but ethylene accumulation was not the sole reason for enhanced anthocyanin production in plants grown under hypoxia. Our results suggest that low oxygen stress induces the production of protective phytochemicals and the free radical scavenging potential in lettuce, which may in turn enhance the functional value. However, further human intervention studies are needed to confirm if enhanced phytochemicals in plants have significant impact in human body. 相似文献
19.
Mango production is often subject to space and tree size management pressures among growers. This study found that root restriction contributed to reduced leaf expansion, thus inhibiting the growth of mango trees. There was even less leaf expansion under water stress conditions. Under well-watered conditions, restricted roots considerably reduced stomatal conductance and leaf water potential compared to control root growth. More rapid reductions in stomatal conductance and leaf water potential occurred under restricted root and water stress conditions compared to control trees. Leaf proline concentrations and abscisic acid (ABA) levels increased as a result of root restriction and water stress but decreased with re-watering. Re-watering also increased stomatal conductance, leaf water potential and peroxidase accumulation in plants with both restricted and non-restricted root growth. Anatomical studies of cross sections of secondary branches showed that root restriction and water stress brought about various changes: compacted cells, as estimated by epidermis thickness and area, as well as by cortex thickness, but with increases in schelerenchyma thickness, phloem and xylem thickness, schelerenchyma area, and pith area and diameter. These results suggest that reduction of soil volume and water stress could effectively control tree size through physiological and morphological changes; thereby bringing higher sustainable returns per hectare and greater effectiveness in orchard management. 相似文献
20.
Cities are characterized by dynamic interactions between socio-economic and biophysical forces. Currently more than half of the global population reside in cities which influence the global biogeochemical cycles and climate change, substantially exacerbating pressures on urban pollution, water quality and food security, as well as operating costs for infrastructure development. Goods and services such as aesthetic values, water purification, nutrient recycling, and biological diversity, that urban ecosystems generate for the society, are critical to sustain. Urban planners are increasingly facing the considerable challenges of management issues for urban ecosystems. Poor understanding of the complementary roles of urban ecology in urban infrastructure, and the functioning of ecosystems and ecological resilience of a complex human-dominated landscape has impeded effective urban planning over time, resulting in social disharmony. Here a complementary framework for urban ecology is proposed, in which ecosystems interact with land use, architecture and urban design – “E-LAUD” – affecting ecosystem and human health, and building on the concept that land uses in urban green areas, road-strips, wetlands, ‘habitat islands’ and urban architecture could synergistically benefit when clustered together in different combinations of urban landscapes. It is proposed that incorporation of the E-LAUD framework in urban planning forms the context of a new interdisciplinary research programme on ecological resilience for urban ecosystems and helps promote ecosystem services. 相似文献