地上竞争与地下竞争对科尔沁沙地榆树幼苗生长的影响

榆树疏林草原对科尔沁沙地植被恢复和景观保护有着重要意义.本文采用双因素两水平控制试验,从幼苗生物量、地下/地上生物量、茎高、根茎比、叶片数等方面,研究了草-树地上、地下竞争对科尔沁沙地榆树幼苗生长的影响.结果表明:对于1年生榆树幼苗,单株平均生物量表现为无竞争＞地上竞争＞全竞争＞地下竞争;地下/地上生物量表现为地下竞争＞全竞争＞无竞争＞地上竞争;幼苗高度表现为地上竞争＞无竞争＞全竞争＞地下竞争;根茎比表现为地下竞争＞全竞争＞无竞争＞地上竞争;叶片数表现为地上竞争＞无竞争＞地下竞争＞全竞争.地下竞争对1年生榆树幼苗生长影响显著,而地上竞争对榆树幼苗生长无显著影响.地上竞争与地下竞争对2年生榆树幼苗生长的影响均不显著.科尔沁沙地草本植物对榆树幼苗生长的影响主要通过地下竞争的方式实现,但地下竞争并没有改变榆树幼苗的资源分配方式.随榆树幼苗龄级的增长,草本植物竞争作用的影响逐渐减弱.     

伊曲康唑联合复方黄松洗液治疗念珠菌性龟头炎临床观察

目的观察伊曲康唑联合复方黄松洗液治疗念珠菌性龟头炎的疗效。方法采用随机对照法观察90例患者。随机平均分为3组,观察伊曲康唑联合复方黄松洗液组(联合组)、伊曲康唑组及复方黄松洗液组治疗念珠菌性龟头炎临床疗效。根据临床症状、体征及真菌清除率判定疗效。结果治疗后2周,联合组、伊曲康唑组临床疗效明显优于复方黄松洗液组,差异有显著性(P0.01、P0.05);联合组临床疗效略高于伊曲康唑组,差异无显著性(P0.05)。三组真菌清除率,联合组和伊曲康唑组明显高于复方黄松洗液组(P0.05)。复发率三组无显著差异(P0.05)。前两组出现4例轻度不良反应。结论复方黄松洗液联合伊曲康唑治疗念珠菌性包皮龟头炎临床效果好,且经济、安全,但与单用伊曲康唑组无显著差异性。提示伊曲康唑联合复方黄松洗液治疗念珠菌性包皮龟头炎的疗效主要源于伊曲康唑。     

浑善达克沙地榆树疏林幼苗更新空间格局

榆树疏林广泛分布于浑善达克沙地,是适应半干旱、半湿润气候的沙地植被类型.采用Ripley的K函数统计方法,分析了浑善达克沙地固定沙丘与丘间低地封育状态下的榆树幼苗空间分布及更新格局.结果表明:两种生境下榆树幼苗密度分别为88株/hm2和77株/hm2,丘间低地更适合幼苗的生长.固定沙丘和丘间低地榆树幼苗均呈聚集分布,但丘间低地的幼苗聚集强度更高.固定沙丘上榆树幼苗与成熟树种群在小尺度上呈负关联,而丘间低地幼苗与成熟树种群呈现较显著的正关联,但二者在大尺度上均无关联性.研究对揭示浑善达克沙地榆树幼苗分布、更新空间格局及其恢复保护具有重要意义.     

莲子磨皮粉淀粉的提取工艺优化及其性质分析

磨皮粉为莲子加工过程中的副产物,本实验以莲子磨皮粉提取蛋白质后的残渣为原料,通过单因素和正交实验优化了其淀粉提取工艺,并分析了该淀粉的颗粒形貌、晶型和糊化特性等性质。结果表明,提取莲子磨皮粉淀粉的最优条件为:0.125 mol/L Na OH提取液、液固比8∶1(m L/g),在温度50℃下提取5.5 h,在此条件下粗淀粉的提取率为94.80%;所得粗淀粉中淀粉含量达88.64%,直链淀粉含量达34.97%;淀粉为C型结晶结构,颗粒多呈椭圆形,粒径范围在3~26μm;起始糊化温度为78.4℃,崩解值为2172.00 m Pa.s,较易糊化且淀粉糊热稳定性较好;回升值为2025.00 m Pa.s,易老化。     

疏林草原榆树种子-幼苗更新过程研究进展

榆树疏林草原曾广泛分布于我国北方农牧交错区,是科尔沁沙地、浑善达克沙地和呼伦贝尔沙地特有的原始景观,景观特征类似于热带稀树草原——萨瓦纳,乔木种类单一,草灌木植被发达,是遏制沙漠扩张的重要屏障。但目前榆树疏林的生长状况大都不良,树龄老化,自然消亡长期得不到更新,特别是种子-幼苗时期更新过程受到人为因素和自然环境的影响,使得榆树疏林生态系统处于崩溃边缘。本文基于国内主要的榆树疏林草原分布区榆树种子-幼苗更新过程研究,列举了榆树疏林种子-幼苗的分布特征以及影响其生长发育的主要因素,并且提出进行榆树种源保护、长期定位观测,开展多学科交叉研究和榆树固沙效果分析的展望,对于榆树疏林植被恢复和重建具有重要的理论价值。     

松嫩草原榆树疏林对不同干扰的响应

榆树疏林是中国东北松嫩草原沙地植被演替的顶极群落,其对维持物种多样性,保持水土,涵养水源等都发挥着重要的功能。过去20a间,榆树疏林在人为干扰(农耕和放牧)下,其群落结构和物种组成发生了巨大变化。在1983年和2004年,对松嫩草原不同人为干扰下榆树疏林群落结构和物种组成等进行调查,结果显示:农耕和放牧一方面使松嫩草原榆树疏林群落多物种消失、生物量和多样性显著下降、植被结构简单化;另一方面,也是导致建群种——家榆低矮化,灌木化的主要因素。     

榆紫金花虫Ambrostoma quadriimpressum Motsch.初步研究

党中央和毛主席关于“在十二年内绿化祖国”的伟大号召提出之后,得到了全国人民热烈的响应,在全国范围内掀起了绿化运动的高潮。可是近年来在东北新植的林带中的幼龄榆树、野生的榆林、护路的(铁路及公路)榆林和城市里行道树中的榆树、公园里用做观尝或树篱的榆树等,都不同程度的遭到了榆紫金花虫的为害。被害的榆树。轻的造成树叶残缺不全,影响了养分的制造;重的则芽、叶全被吃光,影响到结实,甚至导致枯死。如     

雷公藤组培产物的杀虫杀菌活性研究

采用室内生测法研究了雷公藤愈伤组织、悬浮细胞、不定根等组培产物对小菜蛾毒杀、生长发育影响以及不定根提取物对番茄灰霉病等植物病原真菌菌丝生长抑制作用,以明确雷公藤组培产物的生物活性及其应用前景。结果表明,不同雷公藤组培产物对小菜蛾3龄幼虫都具有明显的毒杀作用,悬浮细胞以及不定根的LC50均超过了根皮粉的效果,其中的不定根提取物对小菜蛾3龄幼虫毒杀作用的LC50为根皮粉的1.95倍;不同组培产物提取物对小菜蛾幼虫的生长均有明显的抑制作用,其中不定根提取物处理后每天的小菜蛾体重显著下降,72h后70%左右已经死亡,存活的试虫体重比试验前下降了18.33%;雷公藤不定根提取物对供试的11种植物病原真菌菌丝生长均有一定的抑制作用,有5种的抑制率超过60%,并对番茄灰霉病菌的抑制作用最强,其EC50为10.074mg/mL,且不定根的抑制效果均超过了根皮粉的抑制效果。     

人为干扰对浑善达克沙地榆树疏林的影响

 榆树（Ulmus pumila）疏林灌丛草原是浑善达克沙地植被演替的顶极群落。但近年来,榆树数量减少、树龄老化严重。2001～2002年,在浑善达克沙地榆树疏林集中分布地区,选取了轻度（LD）、中度（MD）和过度（HD）3个不同干扰强度的地点进行实地调查。分析了浑善达克沙地榆树数量     

不同生育期榆树净光合速率对生态因子和生理因子的响应

利用Li-6400便携式光合作用系统,观测了内蒙古浑善达克沙地榆树(Ulmus pumila)的净光合速率(Pn)、上表皮气孔导度(Gs-u)、下表皮气孔导度(Gs-l)等生理因子及大气温度(Ta)、光合有效辐射(PAR)、大气二氧化碳浓度(Ca)和空气相对湿度(RH)等生态因子,应用相关分析、通径分析、决策系数分析及灰色关联分析,系统的研究了榆树Pn在不同生育期的日变化特征及其与生态因子和生理因子间的关系,为深入揭示其生理特征及浑善达克沙地榆树规范化种植提供理论依据。研究表明:1榆树Pn日变化在各生育期均呈双峰型曲线,表现出不同程度的光合"午休"。2榆树Pn在各生育期大小顺序为8月7月9月,其值分别为8.18、7.92μmol CO2m-2s-1和6.52μmol CO2m-2s-1。37、8、9月份PAR、Gs-u与榆树Pn呈显著正相关,且PAR的直接作用和决策系数均最大,Gs-u的直接作用大于其他因子的间接作用,且决策系数仅次于PAR,其他因子在各生育期也表现出对榆树Pn不同程度的影响。4不同生育期榆树对各生态因子和生理因子的响应有所不同,7月份Ta为Pn主要限制变量,8月份RH为Pn主要限制变量,9月份各因子均起增进作用。5不同生育期榆树Pn的变化主要受PAR和Gs-u的影响,但不存在简单的线性相关关系,是所有因子综合影响的结果。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.