Connection of Gnomonia intermedia to Discula betulina and its relationship to other taxa in Gnomoniaceae

Discula betulina is a foliar pathogen on birch (Betula) and Gnomonia intermedia is found on overwintered birch leaves. Perithecia of G. intermedia developed in vitro on colonies of D. betulina isolated from birch tissues in late summer, and single ascospores of G. intermedia consistently developed into colonies similar to D. betulina, producing typical D. betulina conidia. Isolates of D. betulina could be grouped into two mating types, which produced fertile perithecia of G. intermedia when mated with each other. Mycelia from single-ascospore and single-conidial isolates were inoculated onto shoots of downy birch, causing lesions and die-back from which D. betulina was consistently isolated. ITS region ribosomal DNA sequence analysis confirmed the results of the morphological and mating studies, and found that the closest known relatives of G. intermedia/D. betulina are Gnomoniella nana and Sirococcus clavigignenti-juglandacearum. The conclusion from these studies is that D. betulina is the anamorph of G. intermedia.     

害虫预测预报的生态学基础和应用技术研究进展

概述害虫预测预报领域的最新动态,包括理论基础：非线性动力学、景观生态学、生物地理统计学、异质种群和生态系统链接理论,以及应用技术：地碉诱捕、雷达监测、地理信息系统、全球定位系统、遥感、可视化技术和决策支持系统,对于害虫不则报的基础理论研究和害虫管理的生产应用都具有重要的指导意义。     

Scanning Electron Microscopic Observations of Cytoskeletal Arrangement in Wheat Young Leaf Cells and Its Intercellular Connection

By using the techniques of partial digestidon of cell wall and selective extraction authors examined the cytoskeleton in wheat (Triticum aestivum L.) young leaf cells under scanning electron microscope. A three-dimensional cytoskeletal system showing some new features was observed. The cortical network locating beneath the cross wall is an anastomosing organization. Association between nucleus and cell wall by omc skeletal filaments was observed. It is noticeable that there are cytoskeletal filaments, which pass through cell wall, combine adjacent cells cytoskeletal arrays together. Thus it is po sible that an integral skeletal network exist within wheat young leaf tissue.     

茯苓与凤尾菇目间原生质体融合研究初报

以无锁状联合的茯苓次级菌丝和具锁状联合的凤尾菇次级菌丝为亲本制备原生质体,以PEG为促融剂,在高钙、高pH条件下,将茯苓(或凤尾菇)原生质体热灭活,与凤尾菇(或茯苓)原生质体融合,从再生菌株中均能选择选择出能够再形成双核的单核菌株。栽培实验结果显示,单核菌株经诱导形成双核菌株后可以形成子实体或原基,若单核菌株不经诱导,则始终维持稳定的单核状态,且难以形成子实体。     

窝沟封闭和涂氟同时应用对乳磨牙龋病干预的研究

目的:探讨同时应用窝沟封闭和涂氟预防干预乳磨牙预防龋齿的效果,为学龄前儿童乳磨牙龋齿的预防提供新的干预措施。方法:通过Cariostat法对150名学龄前儿童乳磨牙进行龋蚀活跃性试验,将其分为龋活跃高危人群和低危人群,检查其乳磨牙患龋情况,计算龋均。随机抽取30名龋活跃高危人群儿童做为实验组1,30名龋活跃低危人群儿童做实验组2,应用窝沟封闭和多乐氟护齿剂同时对乳磨牙进行龋病预防干预;同时抽取30名龋活跃低危人群做对照组应用多乐氟护齿剂对乳磨牙进行龋病预防干预,于干预后6、12、18个月计算龋病发病率。结果:龋活跃高危人群和低危人群的患龋率分别为68.75%、28.6%,两组比较有显著性差异(P<0.05)。干预后6个月时,实验组1、实验组2、对照组龋病发病率分别为12.3%、11.6%、13.1%,三组比较无显著性差异(P>0.05);12个月时,龋病发病率分别为12.4%、11.8%、23.2%,实验组1、实验组2比较无显著性差异(P>0.05),实验组1、实验组2均显著低于对照组,有显著性差异(P<0.05);18个月时,龋病发病率分别为13.2%、12.9%、29.3%,实验组1、实验组2均显著低于对照组,有显著性差异(P<0.05),但实验组1、实验组2比较无显著性差异(P>0.05)。结论:同时应用窝沟封闭和涂氟对乳磨牙可以有效防龋,降低学龄前儿童的龋发病率。     

The structure and formation of host-parasite pit connections between the red algal alloparasiteHarveyella mirabilis and its red algal hostOdonthalia floccosa

Summary Harveyella mirabilis is a colourless red algal alloparasite which grows on and within its photosynthetic hostOdonthalia floccosa. Cells ofHarveyella establish secondary pit connections (PCs) with other parasite cells and with cells of the host. Small, uninucleate conjunctor cells are produced by parasite cells and remain connected to them by PCs. Conjunctor cells may fuse with either an adjacent host or parasite cell, with the parasite-conjunctor cell PC becoming either a host-parasite or parasite-parasite secondary PC. Occasionally the conjunctor cell does not fuse with an adjacent cell (either host or parasite) and degenerates. The secondary pit plug which forms between a parasite cell and its conjunctor cell always develops with two structurally distinct surfaces characteristic of a host-parasite pit plug. Only if the conjunctor cell fuses with another parasite cell will the structure of the pit plug be altered to that of a parasite-parasite pit plug. Fungal hyphae also invade the region of infection, andHarveyella cells respond by producing nonfunctional conjunctor cells that grow towards adjacent hyphae. Evidence suggests that secondary PCs may be induced to form mechanically, by the physical presence of another cell, rather than in direct response to a message received from an adjacent cell. The mechanism of secondary PC formation described here is similar to that reported for the closely related alloparasiteHolmsella and may be common to a number of red algal parasitic associations. Helen Margaret Quirk, B. Sc. (Hons), M. Sc. (1953–1982), student, research assistant and friend, died after a long illness on October 24, 1982.     

Stormwater drainage pipes as a threat to a stream-dwelling amphipod of conservation significance, Austrogammarus australis, in southeastern Australia

The general hypothesis that catchment urbanization explained the distribution of the threatened, stream-dwelling amphipod Austrogammarus australis (listed under the Victorian Flora and Fauna Guarantee Act 1988) was tested using several surveys of 58 sites in streams draining the Dandenong Ranges on the eastern fringe of Melbourne, Victoria, Australia. More specifically, four catchment-scale elements of urban land, hypothesized as sources of stress to receiving streams, were separated: catchment imperviousness, drainage connection (proportion of impervious areas connected to streams by stormwater pipes), density of unsealed roads and density of septic tanks. The degree to which each attribute independently and jointly explained the occurrence of A. australis was assessed using hierarchical partitioning of logistic regression analyses. Drainage connection independently best explained the occurrence of A. australis, pointing to stormwater drainage design as the priority area of catchment management for the conservation of the species. The separation of urban land use into attributes that characterize likely stressor sources provides a useful framework for assessing and prioritizing the most appropriate management actions to minimize urban-related stresses to aquatic biota.     

The ears of butterflyfishes (Chaetodontidae): ‘hearing generalists' on noisy coral reefs?

Analysis of the morphology of all three otolithic organs (sacculus, lagena and utriculus), including macula shape, hair cell morphology, density, orientation pattern, otolith morphology and the spatial relationships of the swimbladder and ear, reveals that butterflyfishes in the genera Chaetodon (which has anterior swimbladder horns) and Forcipiger (which lacks anterior swimbladder horns) both demonstrate the ear morphology typical of teleosts that lack otophysic connections, fishes that have traditionally been considered to be 'hearing generalists'.     

Ecological benefits of integration of Calamagrostis epigejos ramets under field conditions

We established two independent experiments to estimate the ecological consequences of artificial severing on ramets of the competitively strong perennial grass Calamagrostis epigejos. We compared the responses of mature ramets of different size growing in different environments. Finally, we tested whether the response of young ramets to the severing depends on the density of surrounding vegetation.Severing decreased biomass and number of rhizomes of young ramets but did not affect their competitive tolerance. It decreased survival of mature ramets (probably due to traumata caused by cutting attached rhizomes) but did not influence total biomass of survived ramets. The response of total biomass of mature ramets to severing changed with size of the ramets. Further, biomass allocation to rhizomes changed differently after ramet severing in the two environments.The results suggest that field grown young ramets of Calamagrostis benefit from physiological integration. In contrast, mature ramets seem to be independent units according to the resource economy. Ecological benefits of integration depended on size of ramet clumps: ramets in clump had larger survival probability than control ramets. They also depended on environmental conditions: severing increased formation of new rhizomes at a sand dune subsrate, but it had a negative effect on plants in the forest experimental site. This intra-specific variation should be taken into account when trying to explain ecological patterns of integration benefits of clonal plants.