抗感枯萎病西瓜根际细菌群落多样性比较

本文通过传统微生物培养方法,结合现代分子生物学技术对抗感枯萎病西瓜根际可培养细菌群落进行了比较研究.结果表明,抗病西瓜根际可培养细菌的多样性要高于感病西瓜,且细菌分布的均匀度也高于感病西瓜.表现为抗病西瓜根际可培养细菌的多样性指数H'(1.29)和1/D(30.28)分别高于感病西瓜的H'(1.12)和1/D(2.482).抗病西瓜根际可培养细菌的均匀度指数E(0.72)也高于感病西瓜的E(0.69).抗感西瓜根际分别具有不同的可培养优势群落,抗病西瓜根际可培养优势基因型为基因型1,占51.1%,感病西瓜根际可培养优势基因型为基因型7,占58.7%.     

随机区块法在空间点格局分析中的应用

利用一种以随机模拟技术为基础的空间点格局分析方法--随机区块法对长白山阔叶红松林中5个主要树种的空间格局及空间关系进行了分析.随机区块法利用ICS(t)=s2(t)/x(t)-1来衡量不同尺度t上空间点的分布格局,并通过随机模拟技术构建零假设的95%或99%置信区间,以确定空间点格局偏离零假设的显著性程度.结果表明,除蒙古栎、山荆子、怀槐为随机分布外,其它树种均在局部空间尺度上呈聚集分布;并且绝大多数种对或种组在局部空间尺度上呈正相关关系.随机区块法克服了小样方统计法研究尺度单一的问题,也避免了以空间点距离为基础的点格局分析过程中边缘效应带来的影响和误差,尤其是在多变量点格局分析中具有明显的优势.     

南方丘陵区生态水资源库脆弱度评价——以湖南省为例

以南方生态水资源库为研究对象,提出生态水资源库脆弱性概念,分析了其脆弱性成因和主要表现.从脆弱性成因角度构建了包含10个具体指标的南方丘陵区生态水资源库脆弱性评价指标体系.以湖南为研究案例,运用模糊物元评价模型对85个县级评价单元的生态水资源库脆弱度进行综合评判.结果表明,全省生态水资源库脆弱性等级以中等脆弱为主,其中,微脆弱等级3个,占总评价单元的3.5%,中等脆弱等级70个,占总评价单元的82.4%,强脆弱12个,占总评价单元的14.1%.脆弱度空间分布存在"西部大于东部,南部大于北部"的总体分布态势.其中,以湘西北、湘西南和湘南所构成的外部环形地带和以长沙、衡邵盆地为中心的中东部地带为全省两个比较明显的高脆弱区(带).     

地球的生态负债与人类的可持续发展挑战——WWF《生命行星报告2006》分析

世界自然基金会(WWF)<生命行星报告2006>的最新数据(2003 年)显示,从1961 年以来,人类的"生态足迹"已经增长了3倍.目前的生态足迹已经超出地球自身再生能力的25%.报告中的"生命行星指数"(LPI)显示出自1970年来脊椎动物的数量减少了大约1/3,生物多样性正快速持续地遭到损失.影响 "生态足迹"的最主要因素是生产和使用能源的方式.如生命行星指数所示那样,人类对释放CO2的燃料的需求在不断增长.这些影响气候变化的污染气体占到了生态足迹的48%.将生态足迹与"人类发展指数"(HDI)进行对比发现,目前全球的发展还在继续背离可持续发展之路,人类发展的代内不公平、代际不公平还在加剧,人类向可持续发展的转变之路仍遥远而漫长.     

樱桃属(Cerasus)植物根围微生物多样性

研究了樱桃属(Cerasus) 5种植物本溪山樱(Cs)、大青叶(Cp)、马哈利(Cm)、考特(Cap)、早红宝石(Ca)各主要生长期根围微生物数量、种群组成、Shannom-Wiener指数(H)、丰富度(S)、Pielou均匀度指数(J)、Simpson 优势度(D)和优势微生物种群变化动态.从樱桃根围共分离到细菌18属,优势菌属主要为假单胞菌属(Pseudomonas)、芽孢杆菌属(Bacillus)和黄杆菌属(Flavobacterium);放线菌为链霉菌的12个类群,优势类群主要为白色类群(Albosporus)、吸水类群(Hygroscopicus)和黄色类群(Flavus);真菌6属,优势菌属为青霉属(Penicillium).樱桃根围微生物的多样性指数(H)、丰富度指数(S)、均匀度指数(J) 及优势度指数(D) 随樱桃种类不同而发生变化,细菌的多样性和丰富度指数为Ca＞Cs＞Cp＞Cm＞Cap,放线菌为Ca＞Cp＞Cs＞Cm＞Cap,真菌为Cm＞Ca＞Cp＞Cs＞Cap.各生长期根围微生物种类与数量发生变化,新梢迅速生长期Ca、Cs、Cp和Cm根围微生物种类与数量较多,新梢停长期Cap根围微生物种类与数量较多,落叶期5种樱桃属植物根围微生物种类与数量均较少.     

Environmental correlates of growth traits of the stoloniferous plant Potentilla palustris

Growth form is one of the important life history traits ultimately influencing plant fitness. Potentilla palustris is a stoloniferous plant growing in a range of habitats from densely vegetated wet meadows to acidic transitional fens, and its growth form varies according to habitat. In a four year multi-site comparative study, we investigated which biotic and abiotic characteristics influence most its growth traits. Vegetation composition and physiognomy, as well as numerous abiotic environmental variables, were recorded at 32 study sites located on an altitudinal gradient. Growth traits of P. palustris were best explained by the surrounding vegetation physiognomy and not by abiotic conditions, although the latter obviously represents the factors indirectly influencing its growth. Stolon length traits and branching were positively correlated with vegetation density and height, and negatively with altitude. Plants flowered more in taller vegetation, and leaf area was greater in wetter sites with lower vegetation cover. Potentilla palustris appeared to be well adapted to transitional fens, but its vegetative growth was fastest in wet meadows and alluvial habitats on highly organic humid soils. It produced more branches and larger leaves in alluvial habitats with open water, while it had enhanced generative reproduction in wet meadows. Species composition was less important than vegetation physiognomy. In less favorable habitat types, P. palustris prefers an escape strategy of linear growth. Internode length exhibited pronounced plasticity, increasing particularly in tall dense vegetation of lower altitude, whereas internode number remained fairly constant over various habitats. It is evident that both plastic low cost growth traits (internode elongation), and constant high cost traits (internode number) contribute to the P. palustris escape strategy under tall dense vegetation. Phenotypic plasticity enhances the potential of P. palustris to grow in a wide range of habitats and so increases plant fitness on regional scale.     

Influence of micronization (fine grinding) of soya bean meal and fullfat soya bean on productive performance and digestive traits in young pigs

Two trials were conducted to test the effect of micronization (very fine grinding) of soya bean meal (SBM) and fullfat soya bean (FFSB) on productive performance and digestive traits of piglets. The experimental design was completely randomized with four treatments arranged factorially (SBM and FFSB, micronized and ground). The mean particle size (MPS) was 47 and 881 μm for the SBM and 41 and 778 μm for the FFSB, micronized and ground, respectively. In trial 1 growth traits from 23 to 45 days of age and the coefficient of total tract apparent digestibility (CTTAD) of dietary components at 33 and 45 days of age were assessed. In trial 2 the coefficient of ileal apparent digestibility (CIAD) of dietary components, the pH of the gastro intestinal tract (GIT) and the weight of digestive organs and spleen were measured at 45 days of age. From 23 to 33 days of age pigs fed SBM grew faster (253 g/d versus 213 g/day; P<0.05) and were more efficient (0.87 g/g versus 0.98 g/g; P<0.01) than pigs fed FFSB. For the entire experiment (23–45 days of age) pigs fed SBM tended to grow more (360 g/day versus 324 g/day) and to eat more feed (414 g/day versus 380 g/day) than pigs fed FFSB (P<0.10). The CTTAD of crude protein (0.798 g/kg versus 0.778 g/kg), organic matter (0.864 g/kg versus 0.839 g/kg) and gross energy (0.849 g/kg versus 0.830 g/kg) were higher for pigs fed SBM than for pigs fed FFSB (P<0.001). In addition, CIAD of organic matter (0.765 g/kg versus 0.705 g/kg) and gross energy (0.761 g/kg versus 0.711 g/kg) were higher for SBM than for FFSB diets (P<0.001). The pH of the different segments of the GIT was not affected by the protein source (P>0.10). Particle size did not affect any trait studied (P>0.10). The poor performance and digestibility of pigs fed FFSB as compared to pigs fed SBM might be related to the conditions applied during processing. It is concluded that pigs fed soya bean meal perform better than pigs fed FFSB and that micronization of the soya protein sources does not affect any trait studied.     

一种视网膜锥体细胞退行性变大鼠基础生理值的测定

目的对视网膜锥体细胞退行性变（retinal cone degeneration,RCD）大鼠的主要脏器及血液、生化指标进行检测。方法随机选择BN（Brown Norway）-RCDF2代大鼠,视网膜电图鉴定,取静脉血检测生化指标,并对重要脏器进行准确称量。结果此大鼠脏器质量在雌雄之间除体重、大脑和肾差异有显著性外（P〈0.05）,其余均无差异;脏器系数脑干和小脑雌性显著大于雄性（P〈0.01）;生化指标碱性磷酸酶、葡萄糖、白蛋白、尿素氮、总蛋白雌性高于雄性,总胆固醇、天冬氨酸转氨酶、丙氨酸转氨酶、甘油三酯雌性低于雄性,其中雌性碱性磷酸酶活性显著高于雄性;雌性离子钙浓度显著高于雄性。结论BN-RCD大鼠基础生理值和生化参数均在正常范围内,其中一些参数在性别之间有差异,但与正常SD大鼠相比,天冬氨酸转氨酶、丙氨酸转氨酶、肌酐、钾离子差异显著,葡萄糖、甘油三酯、离子钙有差异。RCD大鼠为遗传性视网膜疾病的研究提供了一种新的突变模式动物。     

ConA引起小鼠肝损伤实验研究

目的探讨conA引起免疫性肝损伤机实验条件。方法测定两个浓度,不同时间点ConA尾静脉注射后小鼠转氨酶水平及肝、脾病理变化。结果15mg／kgConA尾静脉注射后8h,血清转氨酶升高,但病检无明显改变;20mg／kgConA尾静脉注射,脾指数6h达峰值,10h肝脏病理变化显著,转氨酶水平达峰值。结论20mg／kgConA小鼠尾静脉注射6h后脾病变达高峰,10h可引起显著性肝损害。     

一种评价脑循环动力学综合功能的新方法

目的通过对与脑循环功能相关的12个血液动力学参数进行分析,得出能够反映脑循环总体功能的一个综合指标。方法采用病例对照方法,获得120例脑血管疾病患者和130例正常者对照的流行病学资料,年龄在20岁至70岁。综合应用主成分分析、logistic回归分析等方法得到四种综合指标计算模型,并将这四种模型在临床上通过ROC曲线进行初步检验评价。结果在对原始计算数据250例人群的检验中,四个综合指标的ROC曲线下面积分别为0．905、0．901、0．942、0．911。在临床上对另外的年龄为20岁至70岁的775例人群的检验中,四个综合指标的ROC曲线下面积分别为0．943、0．940、0．969和0．945;在对年龄为50岁至60岁的144例人群的检验中,四个综合指标的ROC曲线下面积分别为0．866、0．862、0．935和0．847。讨论对12个参数进行主成分回归后选取前三个主成分进行logistic回归分析后得到的评价模型作为反应脑循环总体功能的综合指标具有较佳的评价能力与更好的稳定性。