蜕皮与中国对虾仔虾肠道杆菌病及肠道堵塞的关系

于１９９６年５月,在青岛市红岛镇后阳育苗场,采用饲养实验的方法对患肠道疾病的中国对虾仔虾的康复进行观察研究。结果表明,中国对虾仔虾的某些肠道疾病的康复与蜕 存在极为密切的关系。肠道杆菌病对虾状幼体和糠虾幼体危害极大,患病个体死亡率为１００％,而患病率的仔虾幼体较高的存活率（３２％）,存活者多数为病症出现时已处蜕皮前期的个体,而在蜕皮间期开始患病的个体极少能发育至蜕皮变态。肠道堵塞是仔虾期纪体的幼体     

Biotic variation in coastal water bodies in Sussex, England: Implications for saline lagoons

Coastal water bodies are a heterogeneous resource typified by high spatial and temporal variability and threatened by anthropogenic impacts. This includes saline lagoons, which support a specialist biota and are a priority habitat for nature conservation. This paper describes the biotic variation in coastal water bodies in Sussex, England, in order to characterise the distinctiveness of the saline lagoon community and elucidate environmental factors that determine its distribution. Twenty-eight coastal water bodies were surveyed for their aquatic flora and invertebrate fauna and a suite of exploratory environmental variables compiled. Ordination and cluster analyses were used to examine patterns in community composition and relate these to environmental parameters. Biotic variation in the coastal water body resource was high. Salinity was the main environmental parameter explaining the regional distribution of taxa; freshwater and saline assemblages were evident and related to sea water ingress. Freshwater sites were indicated by the plant Myriophyllum spicatum and gastropod mollusc Lymnaea peregra, while more saline communities supported marine and brackish water taxa, notably a range of chlorophytic algae and the bivalve mollusc Cerastoderma glaucum. Site community differences were also related to bank slope and parameters describing habitat heterogeneity. A saline lagoon community was discerned within the matrix of biotic variation consisting of specialist lagoonal species with associated typically euryhaline taxa. For fauna, the latter were the molluscs Abra tenuis and Hydrobia ulvae, and the crustaceans Corophium volutator and Palaemonetes varians, and for flora they were the algae Ulva lactuca, Chaetomorpha mediterranea, Cladophora spp. and Enteromorpha intestinalis. One non-native polychaete species, Ficopomatus enigmaticus, also strongly influenced community structure within the lagoonal resource. The community was not well defined as specialist and associated taxa were distributed throughout the spectrum of sites surveyed. Implications for the identification and conservation of saline lagoons are discussed.     

哈尔滨阿勒锦岛国家湿地公园野生种子植物多样性

在哈尔滨市阿勒锦岛国家湿地公园,采用样线和样方调查法,对野生种子植物进行了野外调查,研究该湿地公园野生种子植物的多样性和区系特征.在该湿地公园共记录野生种子植物58科170属272种(包括2亚种和2变种),都为被子植物.其中,物种数较多的科有禾本科(Gramineae)(48种)、菊科(Compositae)(37种)...     

从秦岭蕨类植物区系地理成分论秦岭山地生态分界线的划分

依据2007~2008年野外实地调查以及相关文献资料,运用植物区系地理学和数量生态学方法,分析了秦岭蕨类植物区系的物种组成和地理分布特征,划分了秦岭蕨类植物的垂直带谱,并以此为基础探讨了秦岭山地生态分界线的划分,得出以下主要结论:(1)秦岭共有蕨类植物36科85属311种,优势科为鳞毛蕨科、蹄盖蕨科和水龙骨科,优势属为鳞毛蕨属和耳蕨属;在科属水平上,以热带成分占优势;而种的水平则以温带成分占绝对优势。(2)根据秦岭蕨类植物南北坡垂直带谱的对比分析,南坡海拔1000m左右应该是一条重要的生态分界线。(3)南坡1000m以下蕨类植物区系组成更接近亚热带区系,而其他地带则与温带蕨类植物区系更为接近,DCA排序很好地证明了此结果。综合来看,将南坡海拔1000m作为秦岭山地亚热带与暖温带的生态分界线较为科学。     

Ecological niche modeling and principal component analysis of Krameria Loefl. (Krameriaceae)

Krameria plants are found in arid regions of the Americas and present a floral system that attracts oil-collecting bees. Niche modeling and multivariate tools were applied to examine ecological and geographical aspects of the 18 species of this genus, using occurrence data obtained from herbaria and literature. Niche modeling showed the potential areas of occurrence for each species and the analysis of climatic variables suggested that North American species occur mostly in deserted or xeric ecoregions with monthly precipitation below 140 mm and large temperature ranges. South American species are mainly found in deserted ecoregions and subtropical savannas where monthly precipitation often exceeds 150 mm and temperature ranges are smaller. Principal Component Analysis (PCA) performed with values of temperature and precipitation showed that the distribution limits of Krameria species are primarily associated with maximum and minimum temperatures. Modeling of Krameria species proved to be a useful tool for analyzing the influence of the ecological niche variables in the geographical distribution of species, providing new information to guide future investigations.     

黑龙江伊春红山附近晚二叠世植物群研究的新进展

笔者在伊春红山附近红山组剖面采集了丰富的植物化石.经研究,计有25属58种。大大丰富了前人报道的本组植物化石的内容.分析所获资科,进一步阐述了红山组植物群的组成特征,认为其时代为晚二叠世,而不仅限于晚二叠世晚期.根据过去的化石资料分析.笔者认为“三角山组植物组合”的时代亦为晚二叠世,而不限于晓二叠世早期.在此基础上,本文认为红山组与黄本宏划分的三角山组下部。在岩石组合特征及时代上可以对比.     

辽宁本溪中三叠世苏铁类密脉中国似查米亚

中国似查米亚属Sinozamites Sze是中国北方中、晚三叠世苏铁植物门Cycadophyta代表成分之一.自该属发现以来,该属在分类上属于苏铁目还是本内苏铁目一直不清楚.本文对产于辽宁本溪中三叠世林家组的密脉中国似查米亚S.myrioneurus表皮构造进行了研究.由于标本未保留角质层,故选择超景深显技术,发现该属气孔器属于单唇型,从而确立了该属植物属于苏铁目.研究过程中,既用盐酸又用硝酸来清除化石表面杂质.另根据已有的标本所显示的裂片和羽轴上下过渡关系,对该种羽片进行了部分重建.在此基础上,系统比较了类似的苏铁植物.     

中国吉林大拉子组的时代探讨

大拉子组是我国东北地区早白垩世的典型层位,但该组的具体地质年代一直存在不同的看法。根据最近发现的植物化石材料,通过对大拉子组被子植物优势属的地质分布以及与国内外被子植物群的对比研究,发现大拉子组与北美Potomac带B中部的被子植物群较为相似,结合孢粉、昆虫、叶肢介、介形虫及鱼化石等其他生物化石证据,认为吉林大拉子组的地质时代很可能为阿尔必中期或晚期。     

塔里木板块二叠纪构造演化的古植物群(大植物、孢粉)响应

塔里木板块二叠纪的构造演化导致板块古地理位置、古地貌和古环境的演变(包括气候条件的改变),相应地塔里木板块的植物群在区系性质方面发生了重要变更。该板块二叠纪植物群演替历史分为3个演化阶段:①欧美植物群阶段(阿赛尔期-罗德期);②欧美-安加拉混生植物群阶段(沃德期-吴家坪期)早期;③安加拉植物群阶段(吴家坪期中晚期-长兴期)。