松突圆蚧及友恩蚜小蜂空间分布型和种群消长动态研究

通过对广东省试验林区内松突圆蚧Hemiberlesia pitysophila Takagi及其本地种寄生蜂友恩蚜小蜂Encarsia amicula Viggiani et Ren林间空间分布型和种群消长动态的调查研究发现:两者空间分布型相吻合,都为均匀分布;两者在林间全年种群消长曲线均呈"S"型变化。松突圆蚧种群密度高峰期出现在3月下旬至4月下旬,友恩蚜小蜂种群密度高峰期则分别出现在2月下旬和4月下旬至5月中旬。另外友恩蚜小蜂对松突圆蚧的寄生率全年共出现2个高峰期,分别是2月下旬和4月下旬至6月上旬。结果表明,友恩蚜小蜂和寄主松突圆蚧在林间时空发生规律具有高度一致性。     

松突圆蚧数量、环境因子及马尾松受危害程度三者间的相关性分析

本文旨在找出重要的指标,从而揭示松突圆蚧Hemiberlesia pitysophila Takagi的数量变化与环境因素变化、马尾松Pinus massoniana所受危害程度间相互存在的重要关系。于福建省松突圆蚧发生区选取了4块调查标准样地,对松突圆蚧的6个数量指标和6个环境因子及其对马尾松受危害程度进行了调查,并对调查结果进行了综合相关系数分析。结果表明,环境因子与松突圆蚧数量指标之间存在显著的综合负相关,全N、全P、温度、雌成虫虫口密度、雄成虫虫口密度、2龄若虫虫口密度都是重要指标。松突圆蚧数量指标与马尾松受危害程度之间存在显著的综合正向相关性,环境因子与马尾松受危害程度之间不存在显著的综合相关性。综合相关系数分析所得的各种结果之间非常协调一致,与实际也基本相符。结论认为:环境因子对松突圆蚧数量变化有重要影响,松突圆蚧数量变化对马尾松危害程度有重要影响,而环境因子对马尾松危害程度影响不大;综合相关系数分析法是科学合理的,有一定的创新性和实用性,值得推广研究。     

松突圆蚧空间分布型的研究

应用聚集度指标和回归分析,对松突圆蚧空间分布型进行测定,结果表明：松突圆蚧的若虫在松林中呈聚集分布,聚集度随虫口密度增大而增强;而成虫在松林中呈均匀分布,从而确定出不同种群密度下最适抽样数。通过林间调查和数理统计分析,结果表明：松突圆蚧在松树枝条的东、南、西、北不同方位,以及松树树冠的上、中、下不同层次和幼林、中龄林、成林不同树龄的松林之间的虫口数量差异不显;但在郁闭度不同的松林中虫口数量存在着显差异。     

松突圆蚧对不同马尾松家系危害的初步研究

对受松突圆蚧危害的28个马尾松家系相关的6个指标进行主成分分析和聚类分析,探讨了28个马尾松家系抗松突圆蚧危害的特点。结果表明,家系330、386、318、246、465、662、CK1、232等8个家系不易受松突圆蚧侵害;家系439、458、469等3个家系易受松突圆蚧侵害。     

4种杀虫剂防治松突圆蚧的野外试验

采用平均虫口数、有虫针束率和危害程度3个指标评价毒死蜱、杀扑磷、噻虫嗪和吡虫啉4种杀虫剂对松突圆蚧的种群及危害动态的影响和野外防治效果。结果表明：4种杀虫剂均可产生有效影响,表现为阶段性显降低松突圆蚧种群数量、有虫针束率和危害程度等指标;其中杀扑磷、毒死蜱和噻虫嗪的的显作用期长(60d以上),吡虫啉的显作用期短(60d以下);这种影响主要源于施药后0—60d内杀虫剂对松突圆蚧的有效控制。在毒死蜱、杀扑磷和噻虫嗪作用下,松突圆蚧平均虫口数的校正减退率60d后均高于60％,其余指标则低于50％,但相对较高,可以在生产上使用。     

沿海拔高度松突圆蚧热耐受性的变化

为了解松突圆蚧Hemiberlesia pitysophila Takagi对海拔的热适应性, 通过极端温度暴露试验和过冷却点测定, 比较了不同海拔梯度（80～725 m）上冬季松突圆蚧1龄若虫、2龄性分化前若虫和雌成虫的热耐受性。结果表明: （1）不同海拔松突圆蚧的热耐受性具有显著差异, 主要表现为海拔391 m 区域2龄性分化前若虫和雌成虫的耐寒性, 以及雌成虫的耐热性均显著较强; 除2龄性分化前若虫的耐寒性外, 该虫的热耐受性未表现出随海拔升高而显著增强的趋势。这一结果不支持气候变化假说, 但说明海拔是限制松突圆蚧种群扩张和地理分布的重要因素。（2）海拔梯度上, 1龄若虫和2龄性分化前若虫中耐寒性与耐热性的相关性均不显著, 但在雌成虫中呈显著正相关, 说明海拔梯度上松突圆蚧耐寒性和耐热性的关系与其发育阶段有关。（3）海拔梯度上, 雌成虫的过冷却点与其致死中低温的相关性未表现出显著水平。本文结果有助于深入理解松突圆蚧的热适应性和地理分布特征。     

松突圆蚧种群耐寒性的季节变化

采用过冷却点、低温暴露死亡率、冷识别温度和致死中低温累积等指标评价不同季节松突圆蚧的耐寒性.结果表明:各季节松突圆蚧的过冷却点波动在-22.4～-3.1 ℃之间,以冬季雌成虫的平均过冷却点最低(-14.83 ℃),显著低于夏季雌成虫、冬季1龄若虫和初孵若虫(P＜0.01),但其它发育阶段在冬、夏季之间均无显著差异;冬季1龄若虫、2龄性分化前若虫、2龄性分化后雄若虫、雌成虫和种群总体在-20～0 ℃下的死亡率、冷识别温度和致死中低温累积均明显低于夏季;1龄若虫、2龄性分化后雄若虫和种群总体的致死中低温累积与季节性平均气温均呈显著正相关(R＞R0.05=0.950,n-2=2),但各发育阶段的过冷却点与其致死中低温累积的相关性均未达显著水平.松突圆蚧冬季种群耐寒性最强,夏季种群最弱;该虫耐寒性的这一季节适应性并不依赖于过冷却点,而与气温的季节变化密切相关.     

三种药剂及其复配剂对松突圆蚧的毒力测定

本以机油乳油、毒死蜱及喹硫磷对松突圆蚧1龄若虫进行室内毒力测定,结果表明各药剂对松突圆蚧均有一定的毒力,其中喹硫磷的毒力明显大于其它两种药剂的毒力,但喹硫磷与毒死蜱及机油复配没有增效作用,而机油乳油与毒死蜱以13：10混配,增效作用明显,共毒系数达到405．41．     

松突圆蚧花角蚜小蜂的生物学

松突圆蚧花角蚜小蜂Cocvobius azumai Tachikawa是松突圆蚧Hemiberlesla pitysophila Takagi的重要寄生蜂,1987-1989年从日本引入我国广东省。对松突圆蚧花角蚜小蜂的形态、发育、繁殖、成虫寿命和取食寄主行为等生物学特征进行了观察。该蜂的雌性幼虫是松突圆蚧雌蚧的初级内寄生蜂,而雄性幼虫则是次级寄生蜂,重寄生在同种或它种膜翅目的老熟幼虫、预蛹和蛹上。雌雄两性的形态在所有发育阶段均不相同。交配过的雄蜂喜欢寄生产卵初期和盛期的雌成蚧,对巳寄生的寄主具有识别能力。在19.7℃一30.9℃变温条件下每头雌蜂平均产卵14.95粒,约60%的卵是在最初3天内产出。松突圆蚧花角蚜小蜂雌性蜂在21℃,24℃,27℃和30℃时从卵发育到成虫的平均历期分别为41.24,32.60,25.60和23.00天,发育起点温度10.1℃,有效积温448.3日度。该蜂在广东省一年发生。9-10代。     

松突圆蚧等5种松树有害生物在福建省潜在危险性的定量分析

本参照国内外专家对有害生物的危险性定量分析方法,结合福建省森林资源状况和病虫害发生防治等情况,建立适用于福建省的有害生物潜在危险性的定量分析评价指标体系,并据此对松突圆蚧,红脂大小蠹,萧氏松茎象,湿地松粉蚧,日本松干蚧等5种松树害虫,对福建省的潜在危险性进行了定量分析和评价,结果表明松突圆蚧,萧氏松芪象,日本松干蚧为高度危险的害虫,红脂大小囊,湿地松粉蚧属中度但接近高度危险的害虫,并据此提出了相应的风险管理措施。     

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.