13 resultados para Reciprocal patchiness of resources

em Chinese Academy of Sciences Institutional Repositories Grid Portal


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  克隆植物常常生长在资源异质性分布的环境中,克隆植物特有的生活史特征使其对环境和资源变化产生的反应规范(Reaction norm)具有特殊的表现和适应意义。本文以匍匐茎草本植物蛇莓(Duchesnea indica)和活血丹(Glechoma longituba)为材料,研究克隆植物在不同异质性环境中的反应规范,即可塑性(plasticity)和克隆分株间相互作用(即克隆整合(clonal integration))对表型的影响及其适应意义。 蛇莓和活血丹是具有不同分枝类型的两种匍匐茎草本植物。对于匍匐茎草本植物而言,生境中光资源分布在时间和空间上的变化极为丰富。本文主要研究在不同环境中,这两种克隆植物克隆分株间的相互作用是如何通过影响其形态特征,从而影响其光资源获取策略。 实验涉及了4种光照条件,分为5个部分,分别在大棚和野外进行。 1.同质光环境中蛇莓和活血丹克隆片段的可塑性 在大棚中,将整个克隆片段(clonal fragment)都放置在光照强度分别为自然光照PPFD(Photosynthetic Photon Flux Density)的100%、50%和10%三种不同的同质光环境中,目标是通过比较不同光照强度同质环境中不同基因型的形态特征,揭示匍匐茎草本克隆植物的反应规范及遗传差异。实验结果发现,当光照强度从100% PPFD 降到 50% PPFD时,活血丹增加对地上部分生物量投资,增加部分多投入到匍匐茎上,用于支持匍匐茎实现觅食行为,叶片和叶柄的变化不大。同样条件下,蛇莓的生物量投资却向根部转移,地上部分叶片和叶柄形态上的变化比匍匐茎的形态变化显著,出现增强对光资源吸收能力的变化。当光照强度从50%降到 10%时,活血丹继续增加对地上部分的生物量投资,但由于光照强度弱,几乎不足以维持新的匍匐茎的发生,所有增加的生物量部分都投入到叶片和叶柄的变化上。这种条件下,蛇莓的生物量投资依然向根部转移,叶片和叶柄为增加对光资源吸收能力而发生了相应变化,匍匐茎的新增数减少,形态变化也不大。实验证明,可能由于匍匐茎的发生方式不同,活血丹的匍匐茎节间长度,叶片和叶柄的关联程度比蛇莓相应性状的关联程度强。不同基因型的蛇莓和活血丹对光照梯度的反应有显著差异。 2.异质光环境中蛇莓克隆片段的可塑性 针对克隆植物分株间在相当长的时间里形体相连,而环境异质性可能存在于分株大小的空间尺度,设置异质环境,将蛇莓的不同相连分株放置在不同的光资源斑块中,研究其整合作用在适应异质性环境过程中的作用及其对表型的影响。首先设置同一种资源(光资源)的梯度差异斑块。 在光斑块中,整合作用发生与否、作用方式与资源梯度、分株自身所处斑块的资源条件和分株的年龄结构有关。在不同的条件下,整合作用可能造成对表型的不同影响,从而可能加剧或削弱分株对本地资源的反应(局部反应,local response)。整合作用对分株局部反应的影响强度和方向,在不同基因型间存在明显差异。这些基因型间的差异暗示,整合作用可能也是具有遗传基础的一种独立性状。 3.光块斑和养分斑块共存环境中活血丹克隆片段的可塑性 设置光和养分的资源互补性斑块。将相连分株种植在不同斑块中。当生长在高光低养斑块中的分株与其互补斑块(低光高养斑块)的分株相连时,其适合度相关性状的值增加,根冠比是可塑的,通过相应的形态变化,高光照斑块中的分株捕获光资源的能力增强,但两种斑块中植株的吸收养分的能力却没有大的变化。收益-损耗分析显示整合作用有益于异质环境中的植株,低光高养斑块中植株的生物量获益。实验结果证明了异质环境中相连分株间存在光合产物和养分传递。在这种环境种,分株形态的变化对本地斑块发生趋富反应,形态的改变有助于对本地丰富资源的吸收。这种反应有利于克隆片段对资源的吸收。 4.野外环境中蛇莓克隆片段的可塑性 基于大棚实验资料,对野外林下蛇莓种群进行监测。首先对单株在林下复杂的光环境中的表现进行了跟踪,结果发现,随着分株数目的增加,适合度相关性状值有所提高,而处于不同位置的相连分株在形态上的差异不显著。大棚实验中发现的显著形态变化在具有显著差异的自然环境条件下没有发生,这可能暗示着在资源条件变化频率较高的环境中整合作用的作用方式。分株不是对某一时刻资源条件进行形态特化,而是通过对所扩展的总体区域的总的环境条件调整表型。这样,从克隆片段的水平上看,资源的吸收可能达到较高水平。在密度增大,植株间互相荫蔽使得光照减弱的情况下,匍匐茎的变化没有表现出觅食行为,叶片和叶柄出现增大增长等增强吸收光能力的相应表型变化,证明叶片叶柄是克服光照不足的主要器官。这些结果与大棚实验结果一致。蛇莓基株对于相连分株内部可能具有密度调节功能,从而通过减弱叶片增大的趋势,增长匍匐茎,分散新生分株,使密度保持在一定程度,不对种群的发展造成阻碍作用。非相连分株间随着密度的增大,相互间的作用方式类似于非克隆植物:出现叶片增大,叶柄增长的现象,同时密度制约了适合度相关性状如分株数目等的增加。 5.野外环境中蛇莓种群格局动态 最后,在进化的单位,种群水平上对蛇莓种群在自然界的动态进行了调查。Spearman相关分析,没有发现光资源和测量指标在量上的相关。在自然界中整合作用使大量分散分布、相互连接的分株相互作用,以促进基株对资源的获取。Moran’s I指数分析显示,随时间的推进,各个指标在相关尺度上有所增加。这暗示了整合作用的存在,分株间联系的加强。大棚实验中观察到的关于各个器官的作用的结论在自然界中得到进一步的验证。蛇莓匍匐茎在遮荫环境中不是作为觅食器官。为了争取对更多光资源的吸收,蛇莓在叶片数和叶形态上发生改变。对分株数、叶片数、匍匐茎数目的分布格局的调查显示出没有一定的规律性,而且处于不断的变化中。这一结果可能暗示种群发展过程中处理异质性分布资源的对策的变化。 此外,本文还揭示了可塑性和整合作用在基因型间的差异,针对所发现的现象,从作用的遗传机制上对可塑性及其适应意义进行了讨论。结合分子生物学和地统计学等学科的研究成果,对进一步的实验提出了方法和路线。

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Provisioning along pedestrian trails by tourists much increased the nutrient quality and patchiness of food (NqPF)for Tibetan macaques (Macaca thibetana) at Mt Emei in spring and summer. In the habitat at a temperate-subtropical transition zone, the mncaque's NqPF could be ordered in a decreasing rank from spring summer to autumn to winter With the aid of a radio-tracking system, I collected ranging data on a multigroup community in three 70-day periods representing the different seasons in 1991-92, Rank-order correlation on the data show that with the decline of NqPF; the groups tended to increase days away from the trail, their effective range size (ERS) their exclusive area (EA) and the number of days spent in the EA, and reduced their group/community density and the ratio of the overlapped range to the seasonal range (ROR). In icy/snowy winter; the macaques searched for mature leaves slowly and carefully in the largest seasonal range with a considerable portion that was nor used in other seasons. Of the responses, the ROR decreased with the reduction in group/community density; and the ERS was the function of both group size (+) and intergroup rank (-) when favorite food was highly clumped. All above responses were clearly bound to maximize foraging effectiveness and minimize energy expenditure, and their integration in term of changes in time and space leads to better understanding macaque ecological adaptability. Based on this study and previous work on behavioral and physiological factors, I suggest a unifying theory of intergroup interactions. Ir! addition, as the rate of behavioral interactions,was also related to the group density, I Waser's (1976) gas model probably applies to behavioral, as well as spatial, data on intergroup interactions.

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Controlled vertical drying deposition method was used to make high-quality single crystal close-packed colloidal films formed of different radii polystyrene latex spheres on glass substrates coming from a low concentration water suspension (0.1% volume fraction). Regardless of the spheres radii the film thickness was about 6.3 microns. However, cracks destroyed the crystalline film structure during the colloidal film growth. The effect of particle radius (85-215 nm range) on film cracking was systematically studied using in situ optical fracture monitoring. Primary parallel cracks run along the vertical growth direction, later followed by secondary branched cracks in-between the primary cracks due to residual water evaporation. Quantitative theoretical relationship between the cracks spacing and particles radius was derived and shows good agreement with experimental observations. Normalized cracks spacing is related to a reciprocal ratio of the dimensionless particle radius.

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National Natural Science Foundation of China [40871177]; Project of State Key Lab of Resources and Environmental Information System [088RA304SA]; CAS Knowledge Innovation Project

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In addition to classical methods, namely kriging, Inverse Distance Weighting (IDW) and splines, which have been frequently used for interpolating the spatial patterns of soil properties, a relatively more accurate surface modelling technique is being developed in recent years, namely high accuracy surface modelling (HASM). It has been used in the numerical tests, DEM construction and the interpolation of climate and ecosystem changes. In this paper, HASM was applied to interpolate soil pH for assessing its feasibility of soil property interpolation in a red soil region of Jiangxi Province, China. Soil pH was measured on 150 samples of topsoil (0-20 cm) for the interpolation and comparing the performance of HASM, kriging. IDW and splines. The mean errors (MEs) of interpolations indicate little bias of interpolation for soil pH by the four techniques. HASM has less mean absolute error (MAE) and root mean square error (RMSE) than kriging, IDW and splines. HASM is still the most accurate one when we use the mean rank and the standard deviation of the ranks to avoid the outlier effects in assessing the prediction performance of the four methods. Therefore, HASM can be considered as an alternative and accurate method for interpolating soil properties. Further researches of HASM are needed to combine HASM with ancillary variables to improve the interpolation performance and develop a user-friendly algorithm that can be implemented in a GIS package. (C) 2009 Elsevier B.V. All rights reserved.

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Sustainable water use is seriously compromised in the North China Plain (NCP) due to the huge water requirements of agriculture, the largest use of water resources. An integrated approach which combines the ecosystem model with emergy analysis is presented to determine the optimum quantity of irrigation for sustainable development in irrigated cropping systems. Since the traditional emergy method pays little attention to the dynamic interaction among components of the ecological system and dynamic emergy accounting is in its infancy, it is hard to evaluate the cropping system in hypothetical situations or in response to specific changes. In order to solve this problem, an ecosystem model (Vegetation Interface Processes (VIP) model) is introduced for emergy analysis to describe the production processes. Some raw data, collected by investigating or observing in conventional emergy analysis, may be calculated by the VIP model in the new approach. To demonstrate the advantage of this new approach, we use it to assess the wheat-maize rotation cropping system at different irrigation levels and derive the optimum quantity of irrigation according to the index of ecosystem sustainable development in NCP. The results show, the optimum quantity of irrigation in this region should be 240-330 mm per year in the wheat system and no irrigation in the maize system, because with this quantity of irrigation the rotation crop system reveals: best efficiency in energy transformation (transformity = 6.05E + 4 sej/J); highest sustainability (renewability = 25%); lowest environmental impact (environmental loading ratio = 3.5) and the greatest sustainability index (Emergy Sustainability Index = 0.47) compared with the system in other irrigation amounts. This study demonstrates that application of the new approach is broader than the conventional emergy analysis and the new approach is helpful in optimizing resources allocation, resource-savings and maintaining agricultural sustainability.

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Mapping the spatial distribution of contaminants in soils is the basis of pollution evaluation and risk control. Interpolation methods are extensively applied in the mapping processes to estimate the heavy metal concentrations at unsampled sites. The performances of interpolation methods (inverse distance weighting, local polynomial, ordinary kriging and radial basis functions) were assessed and compared using the root mean square error for cross validation. The results indicated that all interpolation methods provided a high prediction accuracy of the mean concentration of soil heavy metals. However, the classic method based on percentages of polluted samples, gave a pollution area 23.54-41.92% larger than that estimated by interpolation methods. The difference in contaminated area estimation among the four methods reached 6.14%. According to the interpolation results, the spatial uncertainty of polluted areas was mainly located in three types of region: (a) the local maxima concentration region surrounded by low concentration (clean) sites, (b) the local minima concentration region surrounded with highly polluted samples; and (c) the boundaries of the contaminated areas. (C) 2010 Elsevier Ltd. All rights reserved.

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The paramagnetic susceptibility of lanthanum manganite has been measured over a wide temperature range (100-1073 K). On the basis of the thermodynamic equilibria between the various manganese ions with different valence and spin states and the magnetic interactions between the various manganese ions, a semiempirical formula has been proposed to calculate the paramagnetic susceptibilities of lanthanum manganite at different temperatures. The results indicate that most of the discrepancies between the calculated and experimental reciprocal susceptibilities of lanthanum manganite are less than 10% and that the relative contents of the various manganese ions in lanthanum manganite vary with temperature. The relative content of the trivalent manganese ion with a high spin state is dominant over the whole temperature range, while be relative content of the tetravalent manganese ion with a high spin state decreases monotonously with increasing temperature. At 300 K the calculated relative content of the tetravalent manganese ion in lanthanum manganite is about 34%, which is in good agreement with the experimental result (30%). There are some divalent manganese ions present in lanthanum manganite from low temperature to high temperature. The ratio of the relative contents of the tetravalent and divalent manganese ions in the compound varies with temperature. Above 750 K the relative content of the tetravalent manganese ion is less than that of the divalent manganese ion. The variation in the electrical resistivity of lanthanum manganite with temperature has also been interpreted reasonably.

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Current situation of wetland resources in Liaodong bay area are investigated. Main environmental elements are monitored and evaluated. Based on the research, the influences of resources utilization on environment are predicted, and the strategies for protecting environment and sustainable utilization of wetland resources are put forward.

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By seismic tomography, interesting results have been achieved not only in the research of the geosphere with a large scale but also in the exploration of resources and projects with a small scale since 80'. Compared with traditional inversion methods, seismic tomography can offer more and detailed information about subsurface and has been being paid attention by more and more geophysicists. Since inversion based on forward modeling, we have studied and improved the methods to calculate seismic traveltimes and raypaths in isotropic and anisotropic media, and applied the improved forward methods to traveltime tomography. There are three main kinds of methods to calculate seismic traveltime field and its ray path distribution, which are ray-tracing theory, eikonal equation by the finite-difference and minimum traveltime tree algorithm. In ray tracing, five methods are introduced in the paper, including analytic ray tracing, ray shooting, ray bending, grid ray tracing and rectangle grid ray perturbation with three points. Finite-difference solution of eikonal equation is very efficient in calculation of seismic first-break, but is awkward in calculation of reflection traveltimes. We have put forward a idea to calculate traveltimes of reflected waves using a combining way of eikonal equation method and other one in order to improve its capability of dealing with reflection waves. The minimum traveltime tree algorithm has been studied with emphases. Three improved algorithms are put forward on the basis of basic algorithm of the minimum traveltime tree. The first improved algorithm is called raypath tracing backward minimum traveltime algorithm, in which not only wavelets from the current source but also wavelets from upper source points are all calculated. The algorithm can obviously improve the speed of calculating traveltimes and raypaths in layered or blocked homogeneous media and keep good accuracy. The second improved algorithm is raypath key point minimum traveltime algorithm in which traveltimes and raypaths are calculated with a view of key points of raypaths (key points of raypths mean the pivotal points which determine raypaths). The raypath key point method is developed on the basis of the first improved algorithm, and has better applicability. For example, it is very efficient even for inhomogeneous media. Another improved algorithm, double grid minimum traveltime tree algorithm, bases upon raypath key point scheme, in which a model is divided with two kinds of grids so that the unnecessary calculation can be left out. Violent undulation of curved interface often results in the phenomenon that there are no reflection points on some parts of interfaces where there should be. One efficacious scheme that curved interfaces are divided into segments, and these segments are treated respectively is presented to solve the problem. In addition, the approximation to interfaces with discrete grids leads to large errors in calculation of traveltimes and raypaths. Noting the point, we have thought a new method to remove the negative effect of mesh and to improve calculation accuracy by correcting the traveltimes with a little of additional calculation, and obtained better results.

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The work-family relations included positive relationship (work-family enrichment) and negative relationship (work-family conflict). Along with the development of positive psychology, the researchers turned their focus from work-family conflict to work-family enrichment. On the other hand, the research between work and family had just started and most attention was fix on work-family conflict. This research based on the skilled workers in manufacturing, and tried to discuss antecedents and the machanism of work-family relations through a series research which include action relation among job characteristics, work-family relations and outcomes of work, and the action relation among job resource、work-family relations、marital adjustment、work outcomes and role salience. This subject made the investigation to the workers who are working in manufacturing through literature research, questionnaire surveys and other methods. In this subject, several statistical techniques such as Explore Factor Analysis(CFA),Structural Equation Modeling(SEM), multiple-group Analysis were used to get the following conclusion: Firstly, work-family enrichment was an independent variable in work-family conflict, which had more extensively influence. Work-family conflict would increase accompany with the increasing of job demand, and it also would enhance negative work outcomes; work-family enrichment was effected by both job demand and job resource, and it made positive influence to positive and negative work outcomes. Secondly, marital adjustment penetrated into work domain through work-family enrichment inner effect mechanism, and influenced the work outcomes. The work→family enrichment and family→work enrichment could facilitate mutually, marital adjustment influenced the work outcome by the reciprocal relationship of work→family enrichment ↔ family→work enrichment. Finally, the family-role salience had directed loop-enhanced effect to organizational commitment and the importance could also enhance the positive function of work→family enrichment to organizational commitment.