丘陵地区农户生态系统演替分析

丘陵地区农户生态系统演替分析曹凑贵（华中农业大学,武汉４３００７０）ＥｖｏｌｕｔｉｏｎａｒｙＡｎａｌｙｓｉｓｏｎＨｏｕｓｅｋｏｌｄＥｃｏｓｙｓｔｅｍｉｎＨＩＩＩｙＲｅｇｉｏｎｓ￥ＣａｏＣｏｕｇｕｉ（ＣｅｎｔｒａｌＣｈｉｎａＡｇｒｉｃｕｌｄｔｕｒａｌＵｎｉｖｅｒｓｉｔｙ,Ｗｕｈａｎ４３００７０）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｙ,１９９３,１２（２）：５３－５４．Ｔｈｅｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｄｉｆｆｅｒｅｎｔｔｙｐｅｈｏｕｓｅｈｏｌｄｅｃｏｓｙｓｔｅｍｓａｎｄｔｈｅｉｒｅｖｏｌｕｔｉｏｎａｒｙｃｏｒｒｅｌａｔｉｏｎｓａｒｅａｎａｌｙｚｅｄｕｓｉｎｇｆｕｚｚｙｃｌｕｓｔｅｒｉｎｇａｎｄｓｙｓｔｅｍｓｙｎｔｈｅｔｉｃｅｖｏｌｕｔｉｏｎｍｅｔｈｏｄｓ,Ｔｈｅｃａｕｓｅａｎｄｄｉｒｅｃｔｉｏｎｏｆａｇｒｉｃｕｌｔｕｒａｌｄｅｖｅｌｏｐｍｅｎｔｉｎｈｉｌｌｙｒｅｇｉｏｎｓａｒｅｒｅｖｅａｌｅｄａｎｄｓｕｇｇｅｓｔｉｏｎｓｏｎｄｅｖｅｌｏｐｉｎｇｅｃｏ－ａｇｒｉｃｕｌｔｕｒａｌｃｏｎｓｔｒｕｃｔｉｏｎｉｎｌｏｗｅｒｐｒｏｄｕｃｔｉｖｅｈｉｌｌｙｒｅｇｉｏｎｓａｒｅｍａｄｅ．Ｋｅｙｗｏｒｄｓ：ｈｏ     

九十年代生态学的重要观点

九十年代生态学的重要观点Ｅ．Ｐ．Ｏｄｕｍ（ＩｎｓｔｉｔｕｔｅｏｆＥｃｏｌｏｇｙ,ＵｎｉｖｅｒｓｉｔｙｏｆＧｅｏｒｇｅ,Ａｔｈｅｎｓ,ＧＡ３０６０２,ＵＳＡ）在题为“科学进步”的一篇评论性文章（Ｐｏｏｌ,１９９１）中,生物学家ＲｏｂｅｒｔＨａｚｅｎ和物...     

湄洲湾夏季生物有机碳的研究

湄洲弯夏季浮游植物有机碳的调查结果表明,活体有机碳「（ＰＯＣ（Ｂ）」含量为４２．５０－１８５．０μｇ／ｄｍｄｍ＾３,平均值为７７．５ｇ／ｄｍ＾３ＰＯＣ（Ｂ）和叶绿素（Ｃｈｌａ）的转移系数为６２．４;由三磷酸腺苷（ＡＴＰ）计算所得ＰＯＣ（Ｂ）要比由光合作用速率（ＰＲ）所计算的结果大,同时,同化系数（ＰＩ）的变化为０．７８－２．２２ｈ＾－１,它的垂直变化与ＰＯＣ（Ｂ）分布有关。氮是湄洲湾初级生产力的限     

生态系统稳定性研究的历史与现状

生态系统稳定性研究的历史与现状刘增文李雅素（西北林学院,陕西杨陵７１２１００）ＨｉｓｔｏｒｙａｎｄＳｔａｔｕｓｏｆＲｅｓｅａｒｃｈｏｆＥｃｏｓｙｓｔｅｍＳｔａｂｉｌｉｔｙ．ＬｉｕＺｅｎｇｗｅｎ,ＬｉＹａｓｕ（ＮｏｒｔｈｗｅｓｔｅｒｎＣｏｌｅｇｅｏｆＦ...     

湿地及其利用与保护（下）

湿地及其利用与保护（下）陈伟烈（中国科学院植物研究所北京香山１０００９３）（续１９９６年第３１卷第７期第４页）４湿地的合理利用与保护一般而言，我国湿地存在着如下问题：（１）过度利用主要为狩猎、捕围、围垦、采樵、过度放牧等。（２）自然消退严重由于森林破...     

三江平原沼泽生态系统（疏干）演替对土壤动物的影响

三江平原沼泽生态系统（疏干）演替对土壤动物的影响孙帆,赵红音吕宪国,杨青（东北师范大学地理系,长春１３００２４）（中国科学院长春地理研究所,１３００２１）ＩｍｐａｃｔｏｆＳｗａｍｐＥｃｏｓｙｓｔｅｍＳｕｃｃｅｓｓｉｏｎｉｎＳａｎｊｉａｎｇＰｌａｉｎｏ...     

生态系统管理的基本问题

生态系统管理的基本问题赵士洞汪业勖（中国科学院国家计划委员会自然资源综合考察委员会,北京１００１０１）ＳｕｍｍａｒｙｏｎＥｃｏｓｙｓｔｅｍＭａｎａｇｅｍｅｎｔ．ＺｈａｏＳｉｄｏｎｇ,ＷａｎｇＹｅｘｕ（ＣｏｍｍｉｓｉｏｎｆｏｒＩｎｔｅｇｒａｔｅｄＳｕｒ...     

西藏一江两河地区农户生态系统农田能流和物流数量特征

西藏一江两河地区农户生态系统农田能流和物流数量特征王建林（西藏农牧学院林芝８６００００）ＱｕａｎｔｉｔａｔｉｖｅＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＥｎｅｒｇｙＦｌｏｗａｎｄＮｕｔｒｉｅｎｔＣｙｃｌｉｎｇｉｎＨｏｕｓｅｈｏｌｄＥｃｏｓｙｓｔｅｍｓａｌｏ...     

江滩与兴林垦种区钉螺体内几种酶活性的比较

在自动化分析仪上分析了兴林垦种林区内钉螺和草和滩钉螺的总蛋白（ＴＰｒ）含量和谷丙转氨酶（ＧＰＴ）、谷草转氨酶（ＧＯＴ）以及碱性磷酸脂酶（ＡＬＰ）的活力和比活力,及其受林地地下水位高度的影响,结果表明,林地钉螺的ＧＯＴ、ＧＰＴ酶活力和比活力均比滩于钉螺显著提高,ＡＬＰ活力较稳定,但比活力增加,林地内随地下水位降低,钉螺体内总蛋白含量下降,ＧＯＴ、ＧＰＴ比活力均显著升高。     

长江流域农业生态研究现状与展望

长江流域农业生态研究现状与展望徐琪（中国科学院南京土壤研究所,２１０００８）ＣｕｒｒｅｎｔＳｉｔｕａｔｉｏｎａｎｄＰｒｏｓｐｅｃｔｏｆＡｇｒｏ－ｅｃｏｓｙｓｔｅｍＲｅｓｅａｒｃｈｉｎｔｈｅＹａｎｇｔｚｅＲｉｖｅｒＢａｓｉｎ．￥ＸｕＱｉ（ＩｎｓｔｉｔｕｔｅｏｆＳｏｉｌＳｃｉｅｎｃｅ,ＡｃａｄｅｍｉａＳｉｎｉｃａ,Ｎａｎｊｉｎｇ２１０００８）．ＣｈｉｎｅｓｅＪｏｕｒｎａｌｏｆＥｃｏｌｏｇｒ,１９９３,１２（２）：２５－２６．Ｔｈｅｃｕｒｒｅｎｔｓｉｔｕａｔｉｏｎｏｆａｇｒｏ－ｅｃｏｓｙｓｔｅｍｒｅｓｅａｒｃｈｉｎｔｈｅＹａｎｇｔｚｅＲｉｖｅｒｂａｓｉｎａｒｅｂｒｉｅｆｌｙｉｎｔｒｏｄｕｃｅｄａｎｄｔｈｅｆｕｒｔｈｅｒｍａｉｎｒｅｓｅａｒｃｈｆｉｅｌｄｓａｒｅｐｒｏｐｏｓｅｄｆｒｏｍｔｈｅｖｉｅｗｏｆａｇｒｉｃｕｌｔｕｒａｌｓｕｓｔａｉｎａｂｉｌｉｔｙ．Ｋｅｙｗｏｒｄｓ：ａｇｒｏｅｃｏｓｙｓｔｅｍ,ＹａｎｇｔｚｅＲｉｖｅｒｂａｓｉｎ,ａｇｒｉｃｕｌｔｕｒａｌｓｕｓｔａｉｎａｂｉｌｉｔｙ．１土地资源概况长江流域既是古老农业地区,也具有丰富的土地资源类型,为大农业发展提供了广阔的前景。在生态农业建设中典型甚多,并正在     

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.