Associations between soil carbon and ecological landscape variables at escalating spatial scales in Florida,USA

The spatial distribution of soil carbon (C) is controlled by ecological processes that evolve and interact over a range of spatial scales across the landscape. The relationships between hydrologic and biotic processes and soil C patterns and spatial behavior are still poorly understood. Our objectives were to (i) identify the appropriate spatial scale to observe soil total C (TC) in a subtropical landscape with pronounced hydrologic and biotic variation, and (ii) investigate the spatial behavior and relationships between TC and ecological landscape variables which aggregate various hydrologic and biotic processes. The study was conducted in Florida, USA, characterized by extreme hydrologic (poorly to excessively drained soils), and vegetation/land use gradients ranging from natural uplands and wetlands to intensively managed forest, agricultural, and urban systems. We used semivariogram and landscape indices to compare the spatial dependence structures of TC and 19 ecological landscape variables, identifying similarities and establishing pattern–process relationships. Soil, hydrologic, and biotic ecological variables mirrored the spatial behavior of TC at fine (few kilometers), and coarse (hundreds of kilometers) spatial scales. Specifically, soil available water capacity resembled the spatial dependence structure of TC at escalating scales, supporting a multi-scale soil hydrology-soil C process–pattern relationship in Florida. Our findings suggest two appropriate scales to observe TC, one at a short range (autocorrelation range of 5.6 km), representing local soil-landscape variation, and another at a longer range (119 km), accounting for regional variation. Moreover, our results provide further guidance to measure ecological variables influencing C dynamics.     

浅谈中国传统吉祥图案在小区环境小品设计中的运用

本文通过分析国内住宅小区的园林景观设计现状,总结了中国传统吉祥图案的分类,探讨了中国传统吉祥图案在环境小品设计中的作用,指出了吉祥图案在现代环境小品中的设计原则以及环境小品设计中应注意的问题。     

栽培环境对黄秋葵数量性状的影响

为了探究栽培环境对黄秋葵数量性状的影响程度,笔者以海南露地栽培环境为对照,以3种不同类型的6个黄秋葵栽培种为材料,分析大棚和露地2种栽培环境下黄秋葵叶片、果实等14个数量性状的表达结果。结果表明,黄秋葵叶片长度、叶片宽度、第一果实着生高度3个性状受栽培环境影响较明显,果柄长度、果柄粗度、果实长度、果实横径4个性状受环境影响程度与黄秋葵品种类型有关,其中绿秋葵果柄长度与果柄粗度受环境影响程度存在正相关性;五角黄秋葵心室数表达最稳定,多角形黄秋葵心室数易受环境影响。     

Stressed individuals’ preferences for activities and environmental characteristics in green spaces

Everyday modern life offers fewer opportunities for outdoor activities and mental restoration. Outdoor activities in urban green spaces might be a promising means to lower levels of stress. Our hypothesis is that individuals’ Level of Stress (LS) is related to the interaction between preferences for certain perceived sensory dimensions (PSDs) of the outdoor environment and certain types of outdoor activities.A total of 953 randomly selected informants, representative of the Swedish population, answered a postal questionnaire with pre-coded items. The questionnaire consisted of three parts: personal data, preferences for PSDs and for outdoor activities, and self-estimations of health. The study focuses on ill health in relation to Level of Stress (LS). The data was analysed using factor and regression analysis.The results show that individuals reporting high LS are more likely to: be younger adults, women, be on sick-leave, have small children, be dissatisfied with their home environment, experience poorer access to green spaces and, foremost, want to use public green spaces more often.Seventeen different outdoor activity types are identified. The most preferred activity type among the most stressed informants was ‘rest activities’ followed by ‘animal activities’ and ‘walking activities’. All pairs of these three activity types and PSDs showing a significant association were transformed into ‘activity-sensory dimension types’. A regression analysis shows that the most preferred activity-sensory dimension types for informants reporting high LS are ‘animal activities’ in the PSD ‘rich in species’, ‘animal activities’ in the PSD ‘refuge’, and ‘rest activities’ in the PSD ‘nature’.These results may be interpreted as providing information regarding how to plan urban green spaces with certain characteristics that could promote outdoor activities which are preferred by stressed individuals.     

Spatial relationship between human population density, land use intensity and biodiversity in the Czech Republic

We test a hypothesis about the spatial coincidence of human population density and species richness, and analyze effects of land conversion and ecosystem use on species richness and landscape diversity in human dominated Central European country, the Czech Republic. We calculated fraction of aboveground net primary productivity appropriated by humans and compared it to the species richness of vertebrate, invertebrate and plant groups and to landscape diversity index in 560 mapping grid squares with grid size approximately 130?km². Spatial correlations and regressions were established between human population density, appropriation of net primary production, land cover and biodiversity. We found positive spatial coincidence between human population density and species richness. Although the amount of net primary production was not related to species richness in general, we found significant negative spatial relationship between ecosystem use intensity and landscape diversity. As the area of the Czech Republic exhibits relatively high land use intensities, spatial patterns of human impacts have important implications for land management and biodiversity conservation in a cultural landscape.     

Scale-dependent importance of environment, land use and landscape structure for species richness and composition of SE Norwegian modern agricultural landscapes

Knowledge of variation in vascular plant species richness and species composition in modern agricultural landscapes is important for appropriate biodiversity management. From species lists for 2201 land-type patches in 16 1-km² plots five data sets differing in sampling-unit size from patch to plot were prepared. Variation in each data set was partitioned into seven sources: patch geometry, patch type, geographic location, plot affiliation, habitat diversity, ecological factors, and land-use intensity. Patch species richness was highly predictable (75% of variance explained) by patch area, within-patch heterogeneity and patch type. Plot species richness was, however, not predictable by any explanatory variable, most likely because all studied landscapes contained all main patch types – ploughed land, woodland, grassland and other open land – and hence had a large core of common species. Patch species composition was explained by variation along major environmental complex gradients but appeared nested to lower degrees in modern than in traditional agricultural landscapes because species-poor parts of the landscape do not contain well-defined subsets of the species pool of species-rich parts. Variation in species composition was scale dependent because the relative importance of specific complex gradients changed with increasing sampling-unit size, and because the amount of randomness in data sets decreased with increasing sampling-unit size. Our results indicate that broad landscape structural changes will have consequences for landscape-scale species richness that are hard or impossible to predict by simple surrogate variables.     

Total antioxidant activities,phenolics, anthocyanins,polyphenoloxidase activities of selected red grape cultivars and their correlations

Sixteen red grape cultivars (Md. Jean Matthias, Öküzgözü, Muscat Hamburg, Cabarnet Sauvignon, Tekirda? Çekirdeksizi, Gewürztraminer, 2B/56, Kalecik karas?, Carignan, Kokulu Siyah, Alfonse Lavallée, Bo?azkere, Adakaras?, Papazkaras?, Mourvedre and Cinsaut) which are grown in Tekirda? Viticulture Research Institute were analyzed for determination of antioxidant activities, total phenolics, anthocyanins, external colour, polyphenoloxidase activities, sugar and acidity. The lowest antioxidant activity (percentage of inhibition on peroxidation in linoleic acid system; AA) was determined in Tekirda? çekirdeksiz extracts as 87.58% and the highest AA was in Mourvedre (93.78%). Total phenolic content (TP) varied from 817 to 3062 μg/ml GAE in the same varieties, respectively. The total anthocyanin (TA) content ranged from 40.3 to 990.8 mg/l fresh weight. The lowest PPO activity was found in Bo?azkere and the highest was in Kalecik karas?. The total sugar content in the analyzed varieties varied between 13.29 and 24.46%. There was stronger correlation between AA and TP than AA and TA.     

Land use and host community characteristics as predictors of disease risk

Land use has been implicated as a major causal factor in the recent surge of emerging and reemerging zoonotic diseases worldwide. Whirling disease, a parasitic infection caused by the myxozoan, Myxobolus cerebralis, has led to major declines in wild trout populations within the Intermountain West of the USA and is suspected to be exacerbated by land and stream management practices that create favorable habitat for the oligochaete host, Tubifex tubifex. Our objectives were to quantify relationships between whirling disease risk and (1) land use and (2) characteristics of the oligochaete host community within four major watersheds in western Montana. Risk was quantified by the severity and prevalence of infection in caged sentinel rainbow trout. A geographic information system (GIS) was used to model land use (e.g., agriculture, mines) within watersheds. Importance of predictor variables was assessed using regression tree and random forest analyses. A low proportion of riparian forest, high road density, high oligochaete density, and high Limnodrilus hoffmeisteri density were identified as important predictors of high risk. Although we did not examine the mechanisms underlying these correlations, a low proportion of riparian forest and a high road density likely increase stream sedimentation, thus, increasing habitat for oligochaetes. Although relationships identified are not necessarily causal, the ability to predict areas most at risk of M. cerebralis establishment and proliferation using broad scale predictors should serve as a useful management tool within Montana and elsewhere.     

甜和不甜西瓜果实中糖积累及相关酶活性初析

<正>目的与意义:棉子糖半乳糖苷系列寡糖(RFO)的水解对于西瓜果实中糖的积累至关重要,然而大众对于α-半乳糖苷酶在西瓜果实发育过程中的作用知之甚少。之前并没有关于高糖西瓜和低糖西瓜中糖积累及酶活性进行过系统的报道。研究了高糖西瓜和低糖西瓜两个亚种中果实糖代谢机制的差异,及2种西瓜中心果肉和中果皮的糖代谢相     

重庆鲜食葡萄主栽品种巨玫瑰和巨峰的果实性状比较

通过感官品尝评定和果实理化性状测定等,对巨玫瑰和巨峰两个葡萄主栽品种的果实性状进行比较.结果表明,巨玫瑰感官品尝平均分比巨峰高出0.48;果实维生素C含量和可溶性固形物含量比巨峰分别高出3.7μg/g和1%～2%,总酸和单宁含量分别低0.39%和0.182%,风味酸甜适口,且有独特玫瑰香味,品质佳,更受市场欢迎.     

Firmness and activities of polygalacturonase, pectinesterase, β-galactosidase and cellulase in ripening durian harvested at different stages of maturity

The changes in ripening durian aril firmness, water-soluble pectin and polygalacturonase, pectinesterase, β-galactosidase and cellulase activities were determined in fruit harvested at two stages of maturity. Polygalacturonase activity was low in unripe durian aril and increased markedly during ripening. The development of polygalacturonase activity paralleled the formation of water-soluble pectin and decline in firmness. Pectinesterase, β-galactosidase and cellulase activities were high in unripe durian aril and only pectinesterase and β-galactosidase activities increased slightly while cellulase activity was present throughout during ripening. Water-soluble pectin and polygalacturonase and pectinesterase activities were greater in more mature durian aril than in less mature durian aril, whereas firmness and the activities of β-galactosidase and cellulase were less in the more mature durian aril. The roles of polygalacturonase and pectinesterase in softening of ripening durian aril are discussed.     

Projecting land use transitions at forest fringes in the Philippines at two spatial scales

This paper presents two applications of a spatially explicit model of land use change at two spatial scales: a nation-wide application for the Philippines at relatively coarse resolution and an application with high spatial resolution for one island of the Philippines: Sibuyan island, Romblon province. The model is based on integrated analysis of socio-economic and biophysical factors that determine the allocation of land use change in combination with the simulation of the temporal dynamics (path-dependence and reversibility of changes), spatial policies and land requirements. Different scenarios of near-future developments in land use pattern are simulated illustrating the effects of implementing spatial policies. Results from the coarse scale model with national extent mainly serve to identify the overall pattern of land use change and hot zones of deforestation. The detailed application provides more insight in the pattern of land use change and its consequences for ecological processes. The use of the results for environmental assessments is illustrated by calculating spatial indices to assess the impact of land use change on forest fragmentation. It is concluded that spatially explicit modeling of land use change yields important information for environmental management and land use planning. The applications illustrate that the scale of analysis is an important determinant of the model configuration, the interpretation of the results and the potential use by stakeholders. There is no single, optimal, scale for land use change assessments. Each scale enables different types of analysis and assessment: applications at multiple scales therefore give complementary information needed for environmental management.This revised version was published online in May 2005 with corrections to the Cover Date.     

西瓜品种叶部特征与抗旱性的关系

为探讨西瓜叶片特征与抗旱性的关系,找寻能表征西瓜品种抗旱性的叶部特征,通过盆栽试验研究了9个已知抗旱性强弱的西瓜材料叶片结构、水分生理和气孔特性。结果表明:利用西瓜材料单叶面积、叶片解剖特征(栅栏组织/海绵组织、上表皮、下表皮和栅栏组织/叶片厚)和气孔特性(气孔的长/宽、气孔密度、气孔导度、气孔开口大小、单位叶面积气孔相对面积)隶属函数值判定的耐旱级别与大田直接鉴定所得的耐旱等级正相关。西瓜叶片的解剖特征和气孔特性可用于品种抗旱性鉴定,但单一指标不能准确判断西瓜品种的抗旱性。     

Landscape configuration and urban heat island effects: assessing the relationship between landscape characteristics and land surface temperature in Phoenix,Arizona

Landscape Ecology - The structure of urban environments is known to alter local climate, in part due to changes in land cover. A growing subset of research focuses specifically on the UHI in terms...     

外源NAA对甜瓜嫁接愈合关键期保护性酶活性及相关基因表达的影响

通过分析外源施用植物激素NAA(萘乙酸)条件下甜瓜嫁接愈合3个关键时期(隔离层形成期、愈伤组织形成期、维管束桥形成期)保护性酶活性及相关基因表达的变化,探析外源施用NAA对甜瓜愈合过程中生理及其基因表达特性的影响。以蘸取清水的嫁接苗为对照,外源施用40 mg·L-1NAA的嫁接苗为处理,薄皮甜瓜‘银泉一号’为接穗,白籽南瓜‘圣砧一号’为砧木,采用顶端贴接法嫁接。利用石蜡切片筛选嫁接愈合关键时期,测定嫁接愈合过程中4种关键代谢酶(SOD、POD、PPO和PAL)活性,并利用实时荧光定量(qRT-PCR)测定其相关基因表达量。通过石蜡切片观察发现,外源NAA处理后,愈伤组织形成期和维管束桥形成期较对照提前1 d。SOD、POD酶活性呈先升高后降低的趋势,在愈伤组织形成期达到最高值,且酶活性显著高于对照,PAL酶活性在愈合过程中均高于对照,且在维管束桥形成时期达到最高值。PPO酶活性在隔离层形成期显著高于对照,随后其活性略低于对照,但差异不显著。除CmPOD外,外源NAA处理能够显著提高CmFe-SOD、CmCu-Zn-SOD、CmMn-SOD、CmPPO相对表达量,且其变化趋势与酶活性基本一致。综合分析表明,外源施用NAA后,缩短了甜瓜嫁接苗的愈合期,并且能够诱导影响嫁接愈合的关键酶基因表达,提高其相关酶活性,进而促进甜瓜嫁接苗的愈合进程。     

Out on a limb: habitat use of a specialist folivore, the koala, at the edge of its range in a modified semi-arid landscape

Habitat loss and natural catastrophes reduce the resources available to animals. Species can persist if they have access to additional resources and habitats through the processes of landscape complementation and supplementation. In arid and semi-arid ecosystems, where productivity is limited by precipitation, the impact of landscape change and prolonged drought is severe on specialist species whose range boundaries are limited by aridity. We examined the pattern of occurrence by a specialist arboreal folivore, the koala, at the periphery of its biogeographic range, in a semi-arid rangeland landscape. We used hierarchical mixed modelling to examine the effect of landscape change on koala populations and their habitat use during and after a prolonged drought. We found that the tree species and the distance of a site from water courses were the most important determinants for koala presence in these landscapes. Koalas were predominantly detected in riverine habitat along the water courses, which are primary habitat and provide refugia in times of drought and extreme heat. There was a strong positive effect from the interaction between the amount of primary and secondary habitat in the landscape, although individually, the amount of each of these habitats was not important. This shows koalas will persist in more intact landscapes. There was no difference in habitat use between dry and wet years, but we consider that it can take several wet seasons for koalas to expand into habitats away from water courses.     

盆景果树的发展、特点及价值

盆景果树集"艺术欣赏与果实享用"于一身。文章重点阐述盆景果树的定义、发展史与现状、分类与特点、文化和经济的双重价值等内容。