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1.
浙江千岛湖浮游动物群落多样性研究   总被引:14,自引:1,他引:13  
1999年1~12月对浙江千岛湖浮游动物的群落结构,包括密度多样性和生物量多样性进行了 系统研究。轮虫类的多样性指数最高,并且当湖泊在一定的营养水平范围内(贫营养型向中 营养型过渡)时,轮虫的密度多样性与湖泊的营养水平呈现相同的变化趋势。以时间和空间 为参照,对千岛湖两种浮游动物多样性指数与群落因素之间进行了相关分析,得到相关关系 如下:月变化密度多样性=-0.922+4.521×密度均匀度,n=12, r=0.872, p<0.001;生物量多样性=1.99-0.348×透明生物量,n=12, r=-0.868, p<0.01;水平变化密度多样性=2.35+0.008×种类数, n=10, r=0.672, p<0.05;生物量多样性=2.88-1.739×生物量优势度, n=10, r=-0.826, p<0.01。  相似文献   

2.
三江平原沼泽湿地岛状林植物多样性   总被引:5,自引:0,他引:5       下载免费PDF全文
 基于Quick Bird影像选择样地区域,采用样方法进行群落学调查。选取丰富度指数(R)、Simpson指数(D)、Shannon-Wiener指数(H′)、Pielou均匀度指数(Jsw)测度多样性水平。结果表明:19个岛状林共记录到维管植物140种,隶属于44科,102属,与相邻的洪河自然保护区内的同类型群落相比较有些物种已经消失。山杨林(Ass. Populus davidiana)、白桦林(Ass. Betula platyphylla)和杨桦林(Ass. P. davidiana+B. platyphylla)3种群落类型多样性指数在灌木层之间差异显著(p<0.05)。岛状林总体3个层次之间的R、D、H′大小顺序均为草本层>灌木层>乔木层,3者之间差异极显著(p<0.01)。岛状林斑块的物种丰富度与斑块面积(r=0.591, p<0.01)、周长(r=0.674 , p<0.01)和形状指数(r=0.584,p<0.01)极显著相关,而D、H′、Jsw与周长、面积和形状指数相关均不显著。受到一定人为干扰的岛状林群落仍具有较高的植物多样性,其中草本层植物多样性占有重要地位。林窗干扰是导致林下植物多样性较高的重要原因。边缘效应可能是引起群落斑块物种丰富度随着斑块面积、周长和形状指数的增大而增加的重要原因。岛状林群落斑块对于维持该地区的植物多样性具有重要意义。  相似文献   

3.
杀虫剂啶虫脒和毒死蜱对捕食蜘蛛血细胞DNA的损伤作用   总被引:3,自引:0,他引:3  
李锐  李生才  刘佳 《生态学报》2011,31(11):3156-3162
应用蜘蛛血细胞微核试验和单细胞凝胶电泳试验研究了两种杀虫剂啶虫脒和毒死蜱对蜘蛛头胸部和腹部血细胞DNA的损伤作用。结果表明:在啶虫脒和毒死蜱各供试浓度作用下,对蜘蛛血细胞微核率有明显的影响,与对照组相比有显著性差异(p<0.05,p<0.01);且随着两种农药浓度升高,血细胞微核率显著增加,存在明显的剂量-效应关系(啶虫脒浓度与星豹蛛头胸部血细胞微核率相关系数r=0.9284,腹部为r=0.9071;毒死蜱与星豹蛛头胸部血细胞微核率相关系数r=0.9841,腹部为r=0.9793);啶虫脒和毒死蜱对星豹蛛血细胞DNA损伤有明显的剂量-效应关系(啶虫脒浓度与星豹蛛头胸部血细胞DNA损伤相关系数r=0.9838,腹部为r=0.9834;毒死蜱与星豹蛛头胸部血细胞DNA损伤相关系数r=0.9807,腹部为r=0.9659);且两种农药在同种农药同一浓度作用下,对星豹蛛腹部血细胞微核率和DNA损伤程度要明显大于头胸部。  相似文献   

4.
塔里木河中下游地区不同地下水位对植被的影响   总被引:50,自引:2,他引:48       下载免费PDF全文
 根据近几年塔里木河中下游地区的大量监测结果,分析了不同地下水位对植被的影响。结果显示:1)在塔里木河中下游,地下水位与植被盖度和植物种类的回归模型分别可以表示为:Y=159.32e-0.314 8X,R2=0.819 3, p<0.01;Y=9.113e-0.162 3X,R2=0.606 7, p<0.01。2)地下水位对植被的影响在很大程度上是通过改变土壤含水率来实现的,当地下水位在1~4 m时,其回归模型为:Y=64.898e-0.515X,R2=0.727,p<0.01;当地下水位在4~12 m时,Y=21.147e-0.178X,R2=0.658,p<0.01。当地下水位在3.5~4.0 m时,土壤含水率出现明显变化,因此认为3.5 m是塔里木河中下游地区草本植被生态恢复的最低水位。3)通过胡杨叶脯氨酸(Pro)和脱落酸(ABA)在不同水位条件下的含量变化,可以认为引起胡杨水分胁迫的地下水位出现在5.0 m。其后随着水位的降低,胡杨脱落酸的积累更加明显,地下水位与胡杨叶脱落酸含量可以表示为:Y=0.703 5e0.408X,R2=0.830 4, p<0.01。4)通过塔里木河下游输水后的植被调查,当地下水位出现明显升高后,植被的地表生态响应非常明显,乔灌草植被在水位升高至不同水位后均出现相应的变化,说明以上的分析是符合实际的。  相似文献   

5.
滇龙胆中萜类物质积累的动态变化   总被引:1,自引:0,他引:1  
滇龙胆(Gentiana rigescens)为传统中药材。采用单因素方差分析比较不同生长季节滇龙胆的根部及茎叶部位龙胆苦苷、獐牙菜苦苷及当药苷含量的动态变化。结果表明,在不同生长季节,滇龙胆的根部与茎叶部位3种有效成分的含量具明显差异。龙胆苦苷主要积累于根部;獐牙菜苦苷、当药苷主要积累于茎叶部位。相关性分析表明,龙胆苦苷含量受气候因子的影响,月平均温度与茎叶部位龙胆苦苷含量呈极显著负相关(R=-0.57,P〈0.01),月降水量与根部、茎叶部位龙胆苦苷含量呈显著(R=-0.48,P〈0.05)或极显著(R=-0.74,P〈0.01)负相关;根中当药苷含量与獐牙菜苦苷含量呈极显著正相关(R=0.62,P〈0.01),茎叶部位獐牙菜苦苷含量与当药苷含量呈显著正相关(R=0.38,P〈0.05)。研究结果表明,滇龙胆中龙胆苦苷含量受降水量和温度的影响;龙胆苦苷、獐牙菜苦苷及当药苷的含量变动具相关性;9-11月较适宜滇龙胆药材的采收。  相似文献   

6.
 研究了在不同放牧率下形成的不同退化阶段的草地各形态氮素(全氮、硝态氮、铵态氮、无机氮和微生物氮)的变化情况,同时也研究了植被地上绿色生物量与各形态氮素季节变化的同步性关系。土壤全氮含量相对稳定,随草地植被状况和植物生长时期变化不大,说明土壤总氮库有相当的弹性。土壤硝态氮(NO-3-N)、铵态氮(NH+4-N)、无机氮(IN)和微生物氮(Micro-N)季节变化明显。土壤Micro-N和NO-3-N含量随植物生长逐渐降低,到植物枯黄期含量又回复到较高的水平;土壤NH+4-N含量随植物生长有逐渐升高的趋势;IN则随着植物的生长出现低-高-低-高的特点,且与植被地上绿色生物量呈显著负相关(R=-0.247, p<0.01)。在放牧条件下草原植物优先利用NO-3-N,NO-3-N与植被地上绿色生物量有显著的负相关性,是形成草原植被地上绿色生物量的有效性氮素。Micro-N能解释土壤IN 22.3%的变异(R2=0.223, p<0.01),Micro-N是土壤无机氮的重要来源。土壤NH+4-N与Micro-N呈显著负相关(R=-0.222, p<0.01),说明土壤微生物对土壤NH+4-N有偏好吸收。总体上,不同形态的氮素在各土壤层次间差异显著,随土壤层次的加深含量逐步降低。连续放牧11年恢复两年后,各氮素组分对放牧压力消除的响应并不一致。土壤全氮含量与停止放牧前相比变化差异不显著;而Micro-N对放牧压力消失的响应在不同处理下整个生长季的结果比较一致,即以前过度和中度放牧处理的Micro-N含量较高,无牧和轻牧含量较低;IN、NH+4-N和NO-3-N变化比较复杂,在不同放牧恢复处理上结果并不一致。总的来看,以前中度和过度放牧的IN、NH+4-N和NO-3-N含量较高,存在潜在损失的可能。经过两年的恢复,植被地上绿色生物量(8月)过牧处理与无牧处理差异不显著。  相似文献   

7.
作者测定并分析了43只雄貉睾丸宽度、血清睾酮水平的季节性变化。结果表明:睾丸宽度和血清睾酮水平呈明显的年周期季节性变化(p<0.01)。秋分(9月)时,睾丸宽度开始增大(p<0.05 );血清睾酮水平在10月开始升高(p<0.05)。各月雄貉的平均睾酮水平与平均睾丸宽度是极显著的正相关(r=0.83,p<0.01 n=11)。雄貉繁殖季节初期,血清睾酮水平与其首、末次的交配日期呈显著负相关(r=-0.525和r=-0.476,p<0.05,n=19)。  相似文献   

8.
香草醛对杉木幼苗养分吸收的影响   总被引:15,自引:0,他引:15       下载免费PDF全文
 通过模拟实验研究了不同浓度的香草醛对杉木(Cunninghamia lanceolata)幼苗养分吸收和根系活力的影响,结果发现,当浓度为1 mmol·L-1时,香草醛能够显著抑制杉木幼苗对NO-3、NH+4、SO24-及HPO24-离子的吸收和根系活力(p<0.01),而浓度为1×10-2 mmol·L-1时香草醛却促进了杉木幼苗对HPO24-离子的吸收(p<0.01)。这说明高浓度的香草醛能够通过化感作用对杉木幼苗产生影响,降低杉木幼苗的根系活力,进而减少了杉木幼苗对养分离子的吸收,从而影响了杉木幼苗的生长。  相似文献   

9.
基于地形梯度的岩溶槽谷区土地利用空间格局分析   总被引:5,自引:0,他引:5  
王权  李阳兵  刘亚香  胡先培 《生态学报》2019,39(21):7866-7880
揭示当前多因素驱动机制下岩溶槽谷区典型地貌单元在地形梯度上土地利用分布的一般规律与差异性特征具有重要意义。以2017年landsat TM高清影像和30 m×30 m DEM(Digital Elevation Model)为数据源,并结合实地调查,通过地形位分布指数、土地利用多样性指数、土地利用程度指数及土地利用相对合理性指数指标计算,探讨岩溶槽谷区地形梯度的土地利用类型空间分布共同特征与差异。结果表明:(1)岩溶槽谷区土地利用类型呈现山坡(高地形位)-槽坝(低地形位)两种分布格局特色存在,且土地利用类型在地形梯度上主要以低、中、高3种地形位组合模式;(2)土地利用类型在地形梯度上呈现梯度效应,表现出各自分布特征与差异;(3)岩溶槽谷区土地利用多样性、土地利用程度和土地利用合理性在地形梯度上分布格局既存在一些共同性特征,又存在各自差异性;(4)地形梯度土地利用特征差异性是受自然因素、社会经济因素、政策因素共同作用的结果。  相似文献   

10.
巢湖西半湖富营养化时空变化趋势与成因分析   总被引:2,自引:0,他引:2  
收集整理了巢湖西半湖6个国控监测点1983~2008年(26年)主要富营养化指标TP、TN、CODmn、Chla的监测数据,计算了6个监测点和西半湖总体26年的综合营养状态指数(∑TLI图示)时空变化情况。并用Spearm an秩相关系数分析检验了西半湖总体和6个监测点26年∑TLI年变化趋势。结果表明:按总平均∑TLI排列,6个监测点富营养化由重到轻依次为:南淝河入湖区(66.64)〉塘西(64.93)〉十五里河入湖区(63.35)〉派河入湖区(61.38)〉新河入湖区(59.51)〉西半湖湖心(59.18);在显著水平0.05和0.01各点∑TLI均有上升趋势,其中十五里河入湖区(R=0.715)、新河入湖区(R=0.824)和西半湖湖心(R=0.811)以及西半湖总体(R=0.512)∑TLI有显著上升趋势,而南淝河入湖区(R=0.192)、塘西(R=0.045)和派河入湖区(R=0.325)上升趋势均不显著。最后在上述研究的基础上,对巢湖西半湖富营养化时空变化的成因进行了简要分析。  相似文献   

11.
We have created a novel high-throughput imaging system for the analysis of behavior in 7-day-old zebrafish larvae in multi-lane plates. This system measures spontaneous behaviors and the response to an aversive stimulus, which is shown to the larvae via a PowerPoint presentation. The recorded images are analyzed with an ImageJ macro, which automatically splits the color channels, subtracts the background, and applies a threshold to identify individual larvae placement in the lanes. We can then import the coordinates into an Excel sheet to quantify swim speed, preference for edge or side of the lane, resting behavior, thigmotaxis, distance between larvae, and avoidance behavior. Subtle changes in behavior are easily detected using our system, making it useful for behavioral analyses after exposure to environmental toxicants or pharmaceuticals.  相似文献   

12.
The aim was to use some simple way for easier comparison, other expression or recalculation of the QTc duration from one formula to another in order to remove the large QTc differences.Methods and Results: The QT interval duration in 138 young healthy women was taken from our archive. The measured QT interval was corrected for heart rate (QTc) according to nine published regression equations (Bazett, Fridericia, Hodges, Sarma, Lecocq, Rautaharju, Sagie=Framingham, Arrowood, Malik) and compared mathematically by the Pearson correlation coefficient R and graphically by linear correlation.Correlation between two different QTc durations can be of three kinds: small (e.g. Bazett's versus Malik's formulas, R=0.0525, p=0.5405, the QTc values are much dispersed in the graph), larger (Malik's versus Sarma's formulas, R=0.939, p<0.01, the values are less dispersed), and identical (the Rautaharju's versus Arrowood's formulas, R=1.000, p<0.01, all QTc points are situated on one line). The linear correlation QTc1 = a+b·QTc2 enables recalculation from one QTc formula into another, if necessary.In conclusion, the QTc interval durations are differently long according to the QTc formula used. The correlations with the large Pearson R coefficient indicate the QTc pairs inappropriate for recalculation, the small R values indicate the appropriate pairs for recalculation.  相似文献   

13.
It is widely recognized that the tracking of patella is strongly influenced by the geometry of the trochlear groove. Nonetheless, quantitative baseline data regarding correlation between the three-dimensional geometry of the trochlear groove and patellar tracking under in vivo weight-bearing conditions are not available. A combined magnetic resonance and dual fluoroscopic imaging technique, coupled with multivariate regression analysis, was used to quantify the relationship between trochlear groove geometry (sulcus location, bisector angle, and coronal plane angle) and in vivo patellar tracking (shift, tilt, and rotation) during weight-bearing knee flexion. The results showed that in the transverse plane, patellar shift was strongly correlated (correlation coefficient R=0.86, p<0.001) to mediolateral location of the trochlear sulcus (raw regression coefficient β(raw)=0.62) and the trochlear bisector angle (β(raw)=0.31). Similarly, patellar tilt showed a significant association with the trochlear bisector angle (R=0.45, p<0.001, and β(raw)=0.60). However, in the coronal plane patellar rotation was poorly correlated with its matching geometric parameter, namely, the coronal plane angle of the trochlea (R=0.26, p=0.01, β(raw)=0.08). The geometry of the trochlear groove in the transverse plane of the femur had significant effect on the transverse plane motion of the patella (patellar shift and tilt) under in vivo weight-bearing conditions. However, patellar rotation in the coronal plane was weakly correlated with the trochlear geometry.  相似文献   

14.
Little is known of the foraging abilities of children in modern cultures, especially when children forage in groups. Here we present a test of optimal foraging theory in groups of street children working for money. The children we observed were selling bottles of water to drivers distributed in two lanes at a crossroad of Istanbul, Turkey. As predicted by the ideal free distribution (a model of optimal group foraging), the ratio of children working in the two lanes was sensitive to the ratio of cars (and therefore the ratio of potential buyers) present in each lane. Deviations from the ideal free model arose largely from numerical restrictions on the set of possible ratios compatible with a small group size. When these constraints were taken into account, optimal behavior emerged as a robust aspect of the children's group distribution. Our results extend to human children aspects of group foraging that were previously tested in human adults or other animal species.  相似文献   

15.
新技术条件下测度街道绿化品质,实现人眼视角绿化可见度与街道可达性的整合分析。抓取上海的大规模街景数据,基于机器学习算法提取绿化可见度,将其与基于空间网络分析的街道可达性开展叠合分析,并与基于卫星遥感影像的绿化率比较,发现绿化率难以准确展现市民日常生活中绿化接触度。运用新技术和新数据推动精细化规划导控,实践上能实现大规模分析并保证高精度结果,理论上能为规划政策的人本视角转型提供支撑。  相似文献   

16.
We have earlier developed a handheld ultrasound indentation instrument for the diagnosis of articular cartilage degeneration. In ultrasound indentation, cartilage is compressed with the ultrasound transducer. Tissue thickness and deformation are calculated from the A-mode ultrasound signal and the stress applied is registered with the strain gauges. In this study, the applicability of the ultrasound indentation instrument to quantify site-dependent variation in the mechano-acoustic properties of bovine knee cartilage was investigated. Osteochondral blocks (n=6 per site) were prepared from the femoral medial condyle (FMC), the lateral facet of the patello-femoral groove (LPG) and the medial tibial plateau (MTP). Cartilage stiffness (dynamic modulus, E(dyn)), as obtained with the ultrasound indentation instrument in situ, correlated highly linearly (r=0.913, p<0.01) with the values obtained using the reference material-testing device in vitro. Reproducibility (standardized coefficient of variation) of the ultrasound indentation measurements was 5.2%, 1.7% and 3.1% for E(dyn), ultrasound reflection coefficient of articular surface (R) and thickness, respectively. E(dyn) and R were site dependent (p<0.05, Kruskall-Wallis H test). E(dyn) was significantly higher (p<0.05, Kruskall-Wallis Post Hoc test) in LPG (mean+/-SD: 10.1+/-3.1MPa) than in MTP (2.9+/-1.4MPa). In FMC, E(dyn) was 4.6+/-1.3MPa. R was significantly (p<0.05) lower at MTP (2.0+/-0.7%) than at other sites (FMC: 4.2+/-0.9%; LPG: 4.4+/-0.8%). Cartilage glycosaminoglycan concentration, as quantified with the digital densitometry, correlated positively with E(dyn) (r=0.678, p<0.01) and especially with the equilibrium Young's modulus (reference device, r=0.874, p<0.01) but it was not associated with R (r=0.294, p=0.24). We conclude that manual measurements are reproducible and the instrument may be used for detection of cartilage quality in situ. Especially, combined measurement of thickness, E(dyn) and R provides valuable diagnostic information on cartilage status.  相似文献   

17.
We investigated the serum concentration of the interleukin-10 (IL-10), along with cytokines of interleukin-6 (IL-6) family (IL-6, IL-11 and oncostatin M - OSM), as well as soluble receptor for IL-6 (sIL-6R), in 121 patients with multiple myeloma (MM) and 28 healthy subjects. We studied the interactions between IL-10 and other cytokines, and the receptor. The correlation between IL-10 and some clinical and laboratory parameters associated with the disease activity were also analysed. The IL-10 was detectable in all patients with multiple myeloma and in all controls. The IL-10 concentration was significantly increased in myeloma patients compared with healthy persons (mean - 7.09 and 2.1 pg/ml, respectively) (p = 0.008). The level of IL-10 correlated positively with the advanced stage of disease estimated according to the Salmon and Durie classification (I versus III stage - p = 0.03). Higher values of IL-10 were found in patients with the light chain disease, hypercalcaemia, and correlated with the elevated concentrations of C-reactive protein (CRP). IL-6 was detected in 117 of the 121 patients and in all controls. The concentration of IL-6 was statistically increased in MM patients compared with control group (mean - 16.06 and 4.49 pg/ml, respectively) (p = 0.01). We found a positive correlation between IL-10 and IL-6 serum levels in MM patients. The relationship, expressed as Spearman's rank sum coefficient (rho = 0.249, p = 0.006) was significant. IL-11 was detected in 26 of the 121 MM patients and in 3 of the 28 healthy subjects at the mean concentration of 1.2 and 0.6 pg/ml respectively (p > 0.05). OSM was at detectable levels in 51 of the 121 patients and in only 4 of the 28 controls (mean - 3.84 and 0.1 pg/ml, p = 0. 002). The correlation between IL-10 and IL-11 levels in MM patients was not significant, but there was a strong statistical correlation between IL-10 and OSM concentrations (rho= 0.327, p = 0.0002). The serum concentration of sIL-6R was measurable in all patients and all controls (mean - 66.00 and 39.57 ng/ml respectively), but the difference between these groups was not significant. We found significant, positive correlation between the levels of IL-10 and sIL-6R (rho= 0.233, p = 0.01). In conclusion, we state that the serum concentrations of IL-10, IL-6, OSM and sIL-6R in MM patients may be a useful markers for the evaluation of the disease activity.  相似文献   

18.
城市街谷是现代城市最重要的空间形式与特征之一,是城市中使用频率最高、汽车尾气污染最严重、日常人口密度最大的公共空间类型之一。城市街谷不合理的空间配置和结构会造成城市通风自净能力降低,大气污染物浓度增高。本文综述了城市街谷形态、行道树配置、机动车车流量和气象因素等对街谷大气污染物分布的影响,以及数值模拟、风洞试验和实地监测等用于街谷大气污染物分布及扩散研究的相关方法。建议未来以实地监测数据为基础,综合考虑多种因素对街谷大气污染物分布的研究,提出适宜城市大气污染物扩散的城市街谷构建模式,从城市规划和格局优化的角度为城市大气污染物的减控提出科学支撑和优化方案。  相似文献   

19.
 通过测定20个化学因子,利用平均值、变异系数和差异显著性检验,分析研究了中国3种水生水韭属植物中华水韭(Isoetes sinensis)、云贵水韭(I. yunguiensis)和高寒水韭(I. hypsophila)自然居群水体化学性质的特征和差异性。结果显示:这3种水韭属植物生活水体的20个化学因子整体上表现出Ni含量占绝对优势、电导率较低、受干扰较小的共同特征;虽然平均值和变异系数变化较大,但除了pH、P、NO3-N、NO3-和Al具有显著性差异以外,其余各因子在3个种的生活水体间相对稳定不具显著性差异。结合其它的研究结果分析表明:这3种水韭属植物自然居群水体化学性质的差异可能源于这3种水韭属植物生理特征的差异性,对3种水韭属植物的分布不具选择差异性。  相似文献   

20.
Patterns in cell adhesion molecule expression by endothelial cells may play a role in atherogenesis. Previous studies have shown dependence of intracellular adhesion molecule-1 (ICAM-1) expression in human umbilical vein endothelial cells (HUVEC) on shear stress and have indirectly linked ICAM-1 expression to spatial gradients in shear stress. The spatial distribution of ICAM-1 in HUVEC pre-exposed to flow for 8h was determined using fluorescence microscopy and a sudden expansion flow chamber with a 2.66 expansion ratio to simulate gradients in wall shear stress found near arterial branches in vivo. When ICAM-1 expression in the disturbed flow region was compared to theoretical stress distributions obtained from a computational model of sudden expansion flow, a modest trend (R2 = 0.327, p < 0.01)was observed between ICAM-1 and shear stress but the correlation between ICAM-1 and shear stress gradient was insignificant. In contrast, a moderately strong trend (R2 = 0.873, p < 0.01) was evident between ICAM-1 expression and the component of normal stress induced by the expansion. Thus, in this in vitro model, normal stress arising from sudden expansion flow modulates the effect of shear stress on ICAM-1 expression.  相似文献   

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