Quantitative variation as a tool for detecting human-induced impacts on genetic diversity

We propose quantitative genetic variation as a useful tool complementary to molecular variation in order to detect changes in biodiversity caused by different human-induced activities. We simulated a metapopulation setting under a number of realistic scenarios caused by anthropogenic activities (population isolation, reduced carrying capacity or reproductive rates, shifts in the local optima, and enhanced environmental variation or mutational rates). The effects on diversity of these scenarios were assessed for neutral variation estimated from molecular markers and for an additive quantitative trait that represents a typical morphological characteristic subject to stabilising selection promoting local adaptation to environmental conditions. The results show that monitoring quantitative genetic variation can be more informative than neutral variation to detect some human-induced environmental or genetic impacts on diversity, both at intra and interpopulation levels. We also compared the precision of diversity estimates obtained from molecular markers and quantitative traits. Under low migration rates and typical selection intensities for the quantitative trait, the precision of estimates can be substantially larger for a quantitative trait than for a single molecular marker. Thus, about 10-20 (2-4) independent markers are necessary for the precision of estimates of heterozygosity (population differentiation) from molecular markers to reach that of genetic variances (differentiation) from quantitative traits.     

马铃薯腐烂茎线虫的遗传变异及其与生态因子的相关性

马铃薯腐烂茎线虫(Ditylenchus destructor)是世界范围内广泛分布的检疫性线虫,严重危害多种作物.马铃薯腐烂茎线虫为适应不同的生活环境而发生相应的遗传变异,可以通过不同地理种群之间遗传结构的差异来研究环境生态因子对种群遗传结构的影响.利用简单重复序列区间(inter-simple sequence repeat,SSR)分子标记技术研究了我国马铃薯腐烂茎线虫5个群体的遗传多样性、遗传变异,分析了遗传多样性与生态因子的相关性.研究结果表明,马铃薯腐烂茎线虫具有较高的遗传多样性.在种群水平,安徽省太和县种群的遗传多样性最高,河北省昌黎县的遗传多样性最低;在群体水平,5个群体的遗传多样性大小分别为安徽＞山东＞江苏＞河北＞北京.5个群体间具有较小程度的遗传变异,遗传分化系数(Gs)为0.0725;不同种群间具有频繁的基因交流(Nm=6.3933).相关分析表明马铃薯腐烂茎线虫的Shannon遗传多样性与海拔、经度、纬度、年降雨量等成正相关关系,与年均温、最高温、最低温等成负相关关系;马铃薯腐烂茎线虫的遗传距离与地理距离成正相关关系.研究结果认为马铃薯腐烂茎线虫对低温具有较强的适应性,适于在华北、东北等地生长发育,将加强北方地区马铃薯种苗和种薯的管理,对防止马铃薯腐烂茎线虫进一步扩散蔓延提供指导意义.     

Correlation of environmental variables with patterns of distribution and abundance of common and rare freshwater macroinvertebrates

This study explores the environmental factors underlying variation in abundance of common and rare freshwater taxa. Hybrid multidimensional scaling is used to model variation in distribution and abundance of freshwater microinvertebrate taxa over 17 sample sites in the upper catchment of the LaTrobe River, Victoria, Australia. Initial analysis of 40 common taxa revealed high correlations of the ordination space with physico-chemical variables related to temperature, stream order, particle size and water chemistry. Analysis of all 269 taxa, or alternatively of the 229 rarer taxa alone, resulted in ordination spaces that showed high correlations for additional physico-chemical variables, particularly relating to water chemistry. Monte Carlo significance tests supported this finding in demonstrating that the analysis of all taxa produced a greater number of significant correlations between the ordination space and physico-chemical variables.

The additional important environmental correlates revealed by the analysis of the rare taxa suggested that there might be differences in the set of environmental variables that are related to patterns of distribution and abundance of rare versus common taxa. A Monte Carlo test was carried out to test the null hypothesis that the failure to recover some environmental correlates in the analysis of common taxa simply resulted from the small (40) number of taxa involved. Results of the test generally showed that rareness versus commonness could not be implicated in the greater recovery of these water chemistry variables in the analysis of the rare taxa.

The recovery of additional environmental correlates with the inclusion of rare taxa has implications for conservation studies at the community level. Ordination can be used for survey extension where complete information on distribution and abundance of taxa is unavailable. The ability of ordination methods to summarise distribution and abundance of rare taxa, and incorporate their additional information on environmental variation, suggests that representativeness of the ordination space is a useful criterion for reserve selection.     

Soil microbial community response to variation in vegetation and abiotic environment in a temperate old-growth forest

Changes of soil microbial community caused by the heterogeneity of abiotic and biotic environment were studied in the reserve Dobroč, Slovakia. Data on vegetation, microclimate, soil properties and microbial activity were collected on two linear transects crossing both the core of the reserve and the buffer zone.In contrast to expectations, the variation of most environmental variables was comparable or even higher in the buffer zone than in the old-growth forest. Beta diversity was much higher in the natural forest, which coincided with differentiation patterns of trees and understory plants.Mantel correlations between microbial community indicators and environmental variables showed that soil chemistry and vegetation diversity were the most important determinants of microbial activity. Redundance analysis of microbial data identified potassium content, plant richness and influence of fir as the drivers of functional group composition. Inconsistency of correlations of microbial community characteristics with environmental variables indicates that different processes associated with the demography and functions of microbiota are driven by different environmental factors. Amount and variety of substrates available for decomposition seems to influence microbial community more than microclimate.     

鹤地水库浮游植物数量与环境因子的相关分析

浮游植物是水库水环境中的初级生产者和食物链的基础,其数量和生物量与环境因子密切相关,决定水库水生态平衡。通过对鹤地水库浮游植物和水环境因子进行监测,利用SPSS 18.0统计学软件对其数据进行单因素方差分析和相关性分析,探讨浮游植物数量、生物量与环境因子的关系,该研究为保护水质和科学管理提供依据和参考。结果显示:水库浮游植物数量和生物量,除夏季生物量1,2号样点之间差异不显著外,各季节各采样点间都存在显著差异（P < 0.05）,并且是夏季多,冬季少,受水温显著影响。浮游植物生物量和数量与环境因子中水温、pH值、溶解氧、化学需氧量、全磷呈正相关,其中与水温、化学需氧量呈极显著正相关（P < 0.01）,与全磷呈显著正相关（P < 0.05）;与透明度、全氮、氨氮、硝态氮呈负相关,其中与透明度、氨氮呈显著负相关（P < 0.05）。可见,鹤地水库主要是氮污染。因此,强调控制库区周边生活污水和工业污水的过量排放对维持水库生态系统健康非常重要。     

Anticancer activities of thelephantin O and vialinin A isolated from Thelephora aurantiotincta

Thelephora aurantiotincta is an edible mushroom belonging to the genus Thelephora; it grows in symbiosis with pine trees. Recently, phytochemical investigations have revealed that the genus Thelephora is an abundant source of p-terphenyl derivatives. However, their bioactivity has not yet been well characterized. In screening for natural materials with anticancer activity, a T. aurantiotincta ethanol extract (TAE) was found to decrease cell viability in human hepatocellular carcinoma cells (HepG2). In this study, a new p-terphenyl derivative, thelephantin O, and a known compound, vialinin A, were isolated as the principal bioactive components of TAE. These compounds decreased cell viability in HepG2 and human colonic carcinoma cells (Caco2), but not in noncancerous human hepatocytes. This is the first report of the isolation from T. aurantiotincta of selective cytotoxic agents against cancer cells.     

Population genetic structure of Orchesella cincta (Collembola; Hexapoda) in NW Europe, as revealed by microsatellite markers

We studied genetic variation and population differentiation in the springtail Orchesella cincta L. An earlier approach, using allozymes, revealed extremely low variation among and within populations from NW Europe. Microsatellite marker analysis showed higher genetic variation than allozymes, and agreed with the previously reported low population differentiation in the species. Analysis of molecular variance showed that genetic variation within populations amounted to 96.5% of the total variation, whereas the remaining 3.5% is accounted for by population differentiation. Population differentiation, as described by microsatellite markers and with the exception of one population, can be explained by an isolation by distance. Although the microsatellites are short, viz. only up to 12 repeat units, they appear to be useful tools in revealing population genetic structures in O. cincta.     

湖南典型茶树地理种群遗传多样性研究

本文利用RAPD分子标记技术，对4个湖南典型茶树地理种群的240个单株的遗传多样性、种群内和种群间的遗传变异进行研究，结果表明：21个10碱基随机引物共检测到226条谱带，其中多态性谱带为201条，占88.9%。遗传多样性分析结果显示：Shannon's多样性指数为0.43，74.7%的变异分布于群体内，而种群间变异占了25.3%；Nei's指数群体总基因多样度(HT)为0.37，群体内平均基因多样度(HS)0.28，群体间的基因多样度(HST)0.09，群体Nei's基因分化系数（GST）为0.23，说明76.7%的变异存在于种群间，群体内的变异占了总变异的23.3%，与Shannon's多样性指数相比基本一致，均表明种群内有较丰富的遗传变异；种群间的基因流（Nm）为0.74，显示种群间的基因交流有限。     

Environmentally induced changes in amino acid composition in the grain of durum wheat grown under different water and temperature regimes in a Mediterranean environment

Amino acid composition is an important feature in determining the nutritional value of wheat grain for human and animal diets. Environmental conditions are known to influence protein quantity as well as grain production and, in turn, amino acid composition. In this study, grain yield, protein content, and amino acid composition were determined in 10 durum wheat genotypes under three water and temperature regimes in a Mediterranean environment. The highest value for grain-protein content (15.7%) was found in the warmer and driest environment and the lowest (12.8%) in the irrigated environment. Although amino acid composition showed significant variation for all genotypes, with the exception of arginine and cysteine, major changes in amino acid composition were caused by environmental conditions and in particular by water availability and temperature during the grain-filling period, which significantly altered the duration of grain development. The amino acids with the highest percentage of variation between environments were tyrosine (26.4%), lysine (23.7%), methionine (20.3%), threonine (19.3%), and valine (15.6%), whereas phenylalanine (5.1%), glycine (6.4%), and aspartic acid (6.8%) showed the least variation between environments. Whereas the content of glutamine, phenylalanine, and proline increased with the decrease in grain-filling duration, the remaining amino acids tended to diminish, presumably because high temperature and drought favored the deposition of gliadins (proteins particularly rich in glutamine and proline), to the detriment of albumins and globulins (proteins especially rich in threonine, lysine, methionine, valine, and histidine). Despite the negative correlations found between the percentage of protein and its content in essential amino acids, the results indicate that reductions in lysine per unit of food were not very pronounced (0.32 to 0.29 g/100 g of flour) with increases of up 22.7% in grain-protein content, whereas threonine did not change and valine even slightly increased.     

基于NDVI-DFI的矿业开发密集区地表热环境分异效应分析

目前大量研究基于像元二分模型探讨植被覆盖度与城市热岛的关系,基于像元三分模型反演植被覆盖度的研究、植被覆盖度与矿业开发密集区地表热环境分异效应关系的分析尚少见报道。该文利用2000-2018年5期Landsat卫星遥感影像,基于NDVI-DFI像元三分模型反演研究区植被覆盖度,将混合像元分解为光合/非光合植被和裸土3部分。利用辐射传输方程法反演地表温度。借助分级统计法、红蓝差值影像法、相关分析法和回归分析法,分析研究区植被覆盖度时空变化与地表热环境分异扰动效应之间的关系。结果表明:研究区NDVI-DFI特征空间符合像元三分模型的基本假设;相关分析法表明,光合/非光合植被覆盖度和裸土覆盖度变化与地表温度变化之间呈显著相关关系,相关系数分别为-0.81、0.72和0.90;回归分析结果表明,地表温度分别与光合/非光合植被覆盖度和裸土覆盖度呈极显著负相关关系(P<0.01)、不显著正相关关系和极显著正相关关系(P<0.01);光合植被覆盖度每增加10%会使地表温度相应降低0.52℃,裸土覆盖度每增加10%会使地表温度上升0.98℃,非光合植被覆盖度每增加10%会使地表温度相应上升0.61℃。研究结果可为矿业开发密集区地表热环境改善提供定量参考依据。     

Identification and quantification of polyphenolic compounds in Longan (Euphoria longana Lam.) fruit

Regular consumption of fruit and vegetables is associated with a lower risk of some chronic diseases including various forms of cancer and cardiovascular diseases. The health-promoting potential of these foods may be due, in part, to the phytochemical bioactive compounds present in the plants. Fruit of Euphoria longana Lam. (longan) are consumed throughout Asia and are a major crop in Thailand. In the present study phytochemicals were extracted with 70% methanol from peel, pulp, and seed tissues of longan fruit, and the major components were identified as gallic acid, corilagin (an ellagitannin), and ellagic acid. A high-through-put reversed phase HPLC method was developed to determine the content of these three compounds in different parts of the longan fruit and among different cultivars. The analyses showed that there was a large variation in the contents of gallic acid, corilagin, and ellagic acid in different plant tissues and cultivars. Seed contained the highest levels of the three phenolics, and pulp contained the lowest. Among commercial cultivars, Biewkiew and Edor contained the highest levels of gallic and ellagic acid while Srichompoo contained the highest content of corilagin. These three cultivars may be used in directed breeding and cultivation programs and to develop concentrated longan seed extracts to promote good health. Utilization of this byproduct material will support the use of thousands of tons of waste longan seeds after the production of canned longan pulp.     

Temporal variation in breeding,foraging and bird sanctuary visitation by a Southern African Population of great white pelicans Pelecanus onocratalus

Temporal variation in visitation, breeding and foraging during 1977–1978 at a breeding site and a proclaimed bird sanctuary are described for a southern African population of great white pelicans Pelecanus onocratalus. Foraging activity and sanctuary visitation were at low levels during the austral winter (May–August). The pelicans bred at only one site, Dassen Island (33° 25t?, 18° 12′ E), in three major waves in spring and summer (September–March), coinciding with periods of high visitation and foraging activity at Rondevlei Bird Sanctuary (34° 04′S, 18° 30′ E), an important foraging and roosting site within the range of the population. Temporal variation in these aspects of pelican biology is influenced by the fluctuating availability of suitable foraging habitat and fish prey. Water depth and rainfall, those environmental factors which appear to affect the availability of foraging habitat and fish prey, were correlated strongly negatively with measures of pelican foraging activity and sanctuary visitation during 1977–1978. They were also negatively correlated with measures of sanctuary visitation calculated for a 22-year period. Therefore, these factors may have influenced patterns of foraging and visitation of this great white pelican population over the long term.     

土壤水分胁迫下氮素营养对冬小麦光合生理和环境的关系的影响

对冬小麦光合速率 (Pn)、蒸腾速率 (E)、气孔导度 (Gs)和细胞间隙CO2 浓度(Cint)等生理指标与大气CO2 浓度、光合有效辐射、大气温度和大气湿度等环境因子间相关系数作了分析 ;通过求解不同处理相关系数的微分 ,初步研究了大田条件下生理指标对环境因子的灵敏度 ,结果表明 :生理指标与环境间的相关性随施氮量的不同而不同 ;氮素营养改变了生理指标对环境因子响应的灵敏度。     

Bioactive constituent production in St. John's Wort in vitro hairy roots. Regenerated plant lines

A wild strain of Agrobacterium rhizogenes was used to regenerate twelve in vitro plant lines from different hairy roots of H. perforatum (St. John's Wort). The production of the main bioactive constituents was observed even though their yields varied in the different plant lines. Two lines were selected for the hyperoside production (4.9-4.6 mg/gdw) while nine were characterized by significant yields of chlorogenic acid (ranged from 0.47 to 1.09 mg/gdw). Furthermore, one out of twelve lines showed a 10-fold higher hypericin content (0.25 mg/gdw) than that reported for the in vitro shoots in the literature. Morphological and phytochemical features were determined in order to select H. perforatum genotypes enriched in valuable bioactive compounds.     

基于人工神经网络和随机森林学习模型从土壤属性推测关键成土环境要素的研究

土壤与其发生环境密切相关.如何利用土壤属性准确地推测环境要素的信息,是法庭土壤学的重要研究问题.本文以我国东部4省2市(北京、天津、河北、山东、安徽和江苏)为研究区,基于746个土壤表层样本的理化性质和光谱数据构建特征,使用人工神经网络和随机森林两种机器学习模型对海拔高度、年均温、年均降雨量和地表温度四个关键环境要素进...     

重庆县域乡村人居环境综合评价及其空间分异

乡村人居环境是乡村区域内农户生产和生活所需物质和非物质的有机结合体,探求其空间分异特征是实施差异化乡村人居环境整治的重要基础。以重庆市37个区县为研究单元,从基础设施、公共服务、环境卫生条件、居住条件、乡村经济条件5个方面构建了重庆市乡村人居环境综合评价指标体系,运用熵值法测算了各县域评价单元的乡村人居环境综合质量,分析了重庆市乡村人居环境的空间分异特征,为重庆市乡村人居环境整治、优化提供科学参考。结果表明:（1）环境卫生条件在一级指标中权重最大,是影响乡村人居环境质量的重要因素;（2）重庆市乡村人居环境空间分异大致呈现"西高东低"的格局特征;（3）各一级指标综合得分值地域分异特征显著,基础设施、公共服务以及居住条件与乡村人居环境质量呈正相关,环境卫生条件、乡村经济条件与乡村人居环境呈负相关。     

Genotypic and phenotypic changes in wild barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis> subsp. <Emphasis Type="Italic">spontaneum</Emphasis>) during a period of climate change in Jordan

Climate change and other anthropogenic disturbances can lead to the loss of genetic variation and thereby affect evolutionary potential and survival of plant populations in the wild. We examined these predictions in the primary wild relative of barley, Hordeum vulgare L. subsp. spontaneum (K. Koch) Thell., within its center of diversity, in Jordan. Changes in genotypic and phenotypic diversity were assessed using seed samples collected in 1981 and 2012 from the same 18 sites across Jordan. The overall population structure was conserved, but we observed an increase of within population genetic diversity and a reduction in population differentiation. Phenotypic variation differed among years and sites but the magnitude and direction of change variated among sites. While the sampled region became significantly hotter and drier during this period, simple correlation models did not support association between measures of climate change and the observed genetic and phenotypic changes. Agricultural activities that promote disturbance and demographic fluctuations may affect crop wild relatives that grow in agricultural landscapes, in unexpected ways. The observed increase in genetic diversity within populations might be explained by increased migration or by an advantage of increased genetic variation in the face of variable environmental conditions. This study provides a new perspective on the range of possible responses of crop wild relatives to environmental pressures.     

基于信息熵的耕地土壤养分与环境影响因子空间相关性研究

[目的] 探究耕地土壤养分含量空间格局及与环境因子的空间相关性,为区域耕地土壤施肥管控及农业生态环境保护等相关工作提供理论依据。[方法] 以湖北省枣阳市耕地为研究对象,选取土壤有机质、全氮、速效钾、缓效钾和有效磷5种土壤养分指标,并收集整理成土母质、土壤类型、土壤pH值、高程（DEM）、地表起伏度、坡度、植被覆盖度指数（NDVI）、平均气温、平均降水量和土地利用方式10种环境影响因子,利用普通克里金插值和信息熵原理,分析每种土壤养分的空间分布特征以及每种土壤养分空间分异特征与环境因子的相关性。[结果] 枣阳市土壤缓效钾空间异质性不明显,全域含量水平较高;其他4种养分均表现出不同程度的空间异质性。信息熵结果表明,5种土壤养分含量空间格局与成土母质、土壤类型和气候因子相关性均较强但相关程度存在差异;地形因子与全氮和有机质含量空间相关性较强,土壤pH值与土壤速效钾、缓效钾和有效磷相关性较强。[结论] 枣阳市土壤养分格局受自然因素影响较强,但相关性指数K值都较低,说明受到人为施肥与农作物消耗以及灌溉排水导致的土壤水化学反应及养分流失的影响。     

重庆市NDVI对水热条件变化的响应及其空间特征

降水和气温是影响一个地区植被覆盖度的最主要的气候因子。在利用SPOT VGT-NDVI旬数据、重庆市及周边20个气象站点1999-2010年日气温与降水数据以及研究区相关图件资料的基础上,运用时滞互相关分析法分析了旬平均NDVI(TN)与旬均温(TT)和旬降水(TP)的相关性以及时滞情况。结果表明,NDVI与气温和降水之间存在较强的相关性,且NDVI与气温较与降水之间的相关性更强,表明在研究区气温是NDVI变化的限制因子;NDVI与气温和降水之间的相关性和时滞情况存在明显的东南-西北差异,东南地区时滞较长,相关性低,西北地区时滞较短,相关性高;各植被类型NDVI与气温和降水的相关程度高低以及响应速度的快慢决定于各植被类型的生长发育规律及其对气温或降水要求的高低。     

Correlation analyses of phytochemical composition, chemical, and cellular measures of antioxidant activity of broccoli (Brassica oleracea L. Var. italica)

Chemical measures of antioxidant activity within the plant, such as the oxygen radical absorbance capacity (ORAC) assay, have been reported for many plant-based foods. However, the extent to which chemical measures relate to cellular measures of oxidative stress is unclear. The natural variation in the phytochemical content of 22 broccoli genotypes was used to determine correlations among chemical composition (carotenoids, tocopherols and polyphenolics), chemical antioxidant activity (ORAC), and measures of cellular antioxidation [prevention of DNA oxidative damage and of oxidation of the biomarker dichlorofluorescein (DCFH) in HepG2 cells] using hydrophilic and lipophilic extracts of broccoli. For lipophilic extracts, ORAC (ORAC-L) correlated with inhibition of cellular oxidation of DCFH (DCFH-L, r = 0.596, p = 0.006). Also, DNA damage in the presence of the lipophilic extract was negatively correlated with both chemical and cellular measures of antioxidant activity as measured by ORAC-L (r = -0.705, p = 0.015) and DCFH-L (r = -0.671, p = 0.048), respectively. However, no correlations were observed for hydrophilic (-H) extracts, except between polyphenol content and ORAC (ORAC-H; r = 0.778, p < 0.001). Inhibition of cellular oxidation by hydrophilic extracts (DCFH-H) and ORAC-H were approximately 8- and 4-fold greater than DCFH-L and ORAC-L, respectively. Whether ORAC-H has more biological relevance than ORAC-L because of its magnitude or whether ORAC-L bears more biological relevance because it relates to cellular estimates of antioxidant activity remains to be determined. Chemical estimates of antioxidant capacity within the plant may not accurately reflect the complex nature of the full antioxidant activity of broccoli extracts within cells.